Co-reporter:Can Yang;Bo Wang;Linzhu Zhang;Ling Yin; Xinchen Wang
Angewandte Chemie 2017 Volume 129(Issue 23) pp:6727-6731
Publication Date(Web):2017/06/01
DOI:10.1002/ange.201702213
AbstractThe construction of layered covalent carbon nitride polymers based on tri-s-triazine units has been achieved by using nucleobases (adenine, guanine, cytosine, thymine and uracil) and urea to establish a two-dimensional semiconducting structure that allows band-gap engineering applications. This biomolecule-derived binary carbon nitride polymer enables the generation of energized charge carrier with light-irradiation to induce photoredox reactions for stable hydrogen production and heterogeneous organosynthesis of C−O, C−C, C−N and N−N bonds, which may enrich discussion on chemical reactions in prebiotic conditions by taking account of the photoredox function of conjugated carbonitride semiconductors that have long been considered to be stable HCN-derived organic macromolecules in space.
Co-reporter:Dr. Guigang Zhang;Guosheng Li;Zhi-An Lan;Lihua Lin;Dr. Aleksr Savateev;Dr. Tobias Heil;Dr. Spiros Zafeiratos; Xinchen Wang; Markus Antonietti
Angewandte Chemie 2017 Volume 129(Issue 43) pp:13630-13634
Publication Date(Web):2017/10/16
DOI:10.1002/ange.201706870
AbstractPolymeric or organic semiconductors are promising candidates for photocatalysis but mostly only show moderate activity owing to strongly bound excitons and insufficient optical absorption. Herein, we report a facile bottom-up strategy to improve the activity of a carbon nitride to a level in which a majority of photons are really used to drive photoredox chemistry. Co-condensation of urea and oxamide followed by post-calcination in molten salt is shown to result in highly crystalline species with a maximum π–π layer stacking distance of heptazine units of 0.292 nm, which improves lateral charge transport and interlayer exciton dissociation. The addition of oxamide decreases the optical band gap from 2.74 to 2.56 eV, which enables efficient photochemistry also with green light. The apparent quantum yield (AQY) for H2 evolution of optimal samples reaches 57 % and 10 % at 420 nm and 525 nm, respectively, which is significantly higher than in most previous experiments.
Co-reporter:Can Yang;Bo Wang;Linzhu Zhang;Ling Yin; Xinchen Wang
Angewandte Chemie International Edition 2017 Volume 56(Issue 23) pp:6627-6631
Publication Date(Web):2017/06/01
DOI:10.1002/anie.201702213
AbstractThe construction of layered covalent carbon nitride polymers based on tri-s-triazine units has been achieved by using nucleobases (adenine, guanine, cytosine, thymine and uracil) and urea to establish a two-dimensional semiconducting structure that allows band-gap engineering applications. This biomolecule-derived binary carbon nitride polymer enables the generation of energized charge carrier with light-irradiation to induce photoredox reactions for stable hydrogen production and heterogeneous organosynthesis of C−O, C−C, C−N and N−N bonds, which may enrich discussion on chemical reactions in prebiotic conditions by taking account of the photoredox function of conjugated carbonitride semiconductors that have long been considered to be stable HCN-derived organic macromolecules in space.
Co-reporter:Honghui Ou;Pengju Yang;Lihua Lin; Masakazu Anpo; Xinchen Wang
Angewandte Chemie International Edition 2017 Volume 56(Issue 36) pp:10905-10910
Publication Date(Web):2017/08/28
DOI:10.1002/anie.201705926
AbstractAerogel structures have attracted increasing research interest in energy storage and conversion owing to their unique structural features, and a variety of materials have been engineered into aerogels, including carbon-based materials, metal oxides, linear polymers and even metal chalcogenides. However, manufacture of aerogels from nitride-based materials, particularly the emerging light-weight carbon nitride (CN) semiconductors is rarely reported. Here, we develop a facile method based on self-assembly to produce self-supported CN aerogels, without using any cross-linking agents. The combination of large surface area, incorporated functional groups and three-dimensional (3D) network structure, endows the resulting freestanding aerogels with high photocatalytic activity for hydrogen evolution and H2O2 production under visible light irradiation. This work presents a simple colloid chemistry strategy to construct 3D CN aerogel networks that shows great potential for solar-to-chemical energy conversion by artificial photosynthesis.
Co-reporter:Mingwen Zhang, Jinshui Zhang, Yan Chen, Xinchen Wang
Journal of Energy Chemistry 2017 Volume 26, Issue 1(Volume 26, Issue 1) pp:
Publication Date(Web):1 January 2017
DOI:10.1016/j.jechem.2016.07.004
A chemical protocol based on molecular engineering of polymeric matrix is developed for the chemical optimization of ordered mesoporous carbon nitride (OMCN) in this study to address the concerns on the serious nanostructure-induced semiconductive defects, in particular the remarkable hypsochromic shift of absorption threshold and the increased excition dissociation energy. Physical characterizations demonstrate that the successful incorporation of 3-aminothiophene-2-carbonitrile (ATCN) aromatic donor in OMCN matrix can efficiently extend the π-conjugated system, red-shift the optical absorption toward longer wavelengths and promote exciton splitting, thus well overcoming the serious semiconductive defects. In addition, the unique structural benefits of OMCN, such as the well-orientated nanoarchitectures with large specific surface area and uniform nanosized pore, have been well remained in ATCN-modified sample (OMCNA) via adjusting the ATCN/cyanamide molar ratio to minimize the unavoidable matrix disturbance. Hence, an obviously enhanced photocatalytic activity toward H2 evolution and selective oxidation of alcohols are obtained on optimized OMCNA samples, greatly underlining the advantage of molecular engineering in supporting nanostructured photocatalysts.A chemical protocol based on molecular engineering of polymeric matrix is developed for the chemical optimization of ordered mesoporous carbon nitride (OMCN) for photocatalytic hydrogen production with visible light.Download high-res image (92KB)Download full-size image
Co-reporter:Fangsong Guo;Yidong Hou;A. M. Asiri
Chemical Communications 2017 vol. 53(Issue 99) pp:13221-13224
Publication Date(Web):2017/12/12
DOI:10.1039/C7CC07805F
The photocatalytic activity of protonated ordered mesoporous carbon nitride (pom-CN) was significantly improved by assembling anionic [Mo3S13]2− clusters as cocatalysts onto the surface and channel of pom-CN via electrostatic interactions. This work demonstrates the feasibility of employing solution chemistry to assemble co-catalysts in the form of ionic clusters as building blocks into a photosynthetic architecture.
Co-reporter:Lihua Lin;Chong Wang;Wei Ren;Honghui Ou;Yongfan Zhang
Chemical Science (2010-Present) 2017 vol. 8(Issue 8) pp:5506-5511
Publication Date(Web):2017/07/24
DOI:10.1039/C7SC00900C
Photocatalytic water splitting is an ideal pathway to produce hydrogen for the future energy supply due to the sustainability of solar energy and the mild reaction conditions. In the past four decades, many inorganic semiconductor photocatalysts have been studied for this purpose. In recent years, conjugated polymers, in particular covalent carbon nitride frameworks, have rapidly emerged as a new family of photocatalysts. However, the use of conjugated photocatalysts in overall water splitting in the absence of sacrificial agents has been much less reported. Herein, we used surface kinetic control to photocatalyze overall water splitting by a covalent carbon nitride semiconductor with a crystalline poly(triazine imide) (PTI) frameworks. Our study demonstrates that the loading of a Pt co-catalyst on the PTI surface plays the key role in inducing overall water splitting. The co-deposition of a cobalt species can effectively increase the photocatalytic activity and adjust the ratio of H2 and O2 produced, as well as enhancing the stability of the photocatalyst. The optimal sample with the dual co-catalysts shows an apparent quantum yield of 2.1% for the overall water splitting reaction.
Co-reporter:Guigang Zhang;Zhi-An Lan
Chemical Science (2010-Present) 2017 vol. 8(Issue 8) pp:5261-5274
Publication Date(Web):2017/07/24
DOI:10.1039/C7SC01747B
Graphitic carbon nitride based polymers, being metal-free, accessible, environmentally benign and sustainable, have been widely investigated for artificial photosynthesis in recent years for the photocatalytic splitting of water to produce hydrogen fuel. However, the photocatalytic stoichiometric splitting of pure water into H2 and O2 with a molecular ratio of 2 : 1 is far from easy, and is usually hindered by the huge activation energy barrier and sluggish surface redox reaction kinetics. Herein, we provide a concise overview of cocatalyst modified graphitic carbon nitride based photocatalysts, with our main focus on the modulation of the water splitting redox reaction kinetics. We believe that a timely and concise review on this promising but challenging research topic will certainly be beneficial for general readers and researchers in order to better understand the property–activity relationship towards overall water splitting, which could also trigger the development of new organic architectures for photocatalytic overall water splitting through the rational control of surface chemistry.
Co-reporter:Mingwen Zhang, Zhishan Luo, Min Zhou, Guigang Zhang, Khalid A. Alamry, Layla A. Taib, Abdullah M. Asiri, Xinchen Wang
Applied Catalysis B: Environmental 2017 Volume 210(Volume 210) pp:
Publication Date(Web):5 August 2017
DOI:10.1016/j.apcatb.2017.03.080
•Binary Ni-Co LDHs/carbon nitride layered junctions are developed.•The geometric similarity and electrical coupling of Ni–Co LDHs with CNU facilitate the formation adaptive layered junctions.•The enhanced photocatalytic activity and selectivity toward water oxidation is achieved for the Ni-Co LDHs/carbon nitride hybrids.•An effective interfacial 2D junction between water oxidation catalysts and semiconductors is beneficial for artificial photosynthesis.The oxidation side of overall water splitting reaction, involving multiple electron transfer, OH bond cleavage, and OO bond formation, is a vital step to control the overall activities of water spitting. However, this process is usually restricted by the huge energy barrier and sluggish reaction kinetics. Recently, cobalt-based nanomaterials have been proved to be capable of decreasing the activation energy and accelerating the reaction kinetics. In principle, many factors will largely affect the activities, such as the loading contents, the size and structure of the cocatalysts. In order to achieve an overall enhancement of catalytic activities, it is reasonable to fabricate a tight and well matching junction that could efficiently promote the interface charge migration and separation. Herein, a high-performance water oxidation junction with layered structure was fabricated via in-situ growth of Ni-Co layered double hydroxides (LDHs) on graphitic carbon nitride nanosheets. Owing to the similarity of their layered stacking geometry, LDHs will strongly anchor on the surface of carbon nitride nanosheets, which could favor the photocatalytic water oxidation activities. As expected, the optimized binary catalysts showed remarkably enhanced activity for the photocatalytic water oxidation to release oxygen, which was 6.5 times higher than that of pure carbon nitride materials without loading the cocatalyst.Download high-res image (144KB)Download full-size image
Co-reporter:Liuyong Chen
Chemical Communications 2017 vol. 53(Issue 88) pp:11988-11991
Publication Date(Web):2017/11/02
DOI:10.1039/C7CC05557A
The synthesis of boron carbon nitride (BCN) with special morphologies via a simple pathway is still a major challenge. A novel and facile biotemplating method has been presented to synthesize boron carbon nitride tubes (BCNTs) by using kapok fibers (KFs) as both biotemplates and carbonaceous sources. The BCNT photocatalysts can catalyse hydrogen evolution from water under visible light illumination.
Co-reporter:Baihua Long;Yun Zheng;Lihua Lin;Khalid A. Alamry;Abdullah M. Asiri
Journal of Materials Chemistry A 2017 vol. 5(Issue 31) pp:16179-16188
Publication Date(Web):2017/08/08
DOI:10.1039/C6TA09802A
Large pore three-dimensional cage-type mesoporous carbon nitride semiconductors were successfully synthesized by employing SBA-16 templates which are prepared by hydrothermal methods at higher temperatures. These samples were characterized by using various techniques, and their photocatalytic H2 production properties were investigated under visible light (λ > 420 nm) irradiation. The results have shown that the textural parameters of the carbon nitride semiconductors can be easily tuned by simple adjustment of the synthesis temperature of the template SBA-16 silica, and carbon nitride semiconductors can be truly reversely replicated from the cubic structure of the template silica synthesized at a temperature of 180 and 200 °C. The large pore cage-type mesoporous carbon nitride semiconductor cast from mesoporous silica at the hydrothermal temperature of 200 °C exhibits a remarkably enhanced photocatalytic activity towards hydrogen evolution, as compared to either disordered mesoporous g-CN or bulk g-CN prepared by our previous synthetic approaches.
Co-reporter:Dr. Yuanxing Fang; Xinchen Wang
Angewandte Chemie International Edition 2017 Volume 56(Issue 49) pp:15506-15518
Publication Date(Web):2017/12/04
DOI:10.1002/anie.201707824
AbstractMetal-free catalysts have distinct advantages over metal and metal oxide catalysts, such as lower cost as well as higher reliability and sustainability. Among the nonmetal compounds used in catalysis, boron-containing compounds with a few unique properties have been developed. In this Minireview, the recent advances in the field of boron-containing metal-free catalysts are presented, including binary and ternary boron-containing catalytic materials. Additionally, the three main applications in catalysis are considered, namely, electrocatalysis, thermal catalysis, and photocatalysis, with the role of boron discussed in depth for each specific catalytic application. Boron-containing compounds could have a substantial impact on the field of metal-free catalysts in the future.
Co-reporter:Fangsong Guo;Dr. Pengju Yang;Zhiming Pan;Xu-Ning Cao; Zailai Xie; Xinchen Wang
Angewandte Chemie International Edition 2017 Volume 56(Issue 28) pp:8231-8235
Publication Date(Web):2017/07/03
DOI:10.1002/anie.201703789
AbstractCarbon-based catalysts have demonstrated great potential for the aerobic oxidative dehydrogenation reaction (ODH). However, its widespread application is retarded by the unavoidable deactivation owing to the appearance of coking or combustion under ODH conditions. The synthesis and characterization of porous structure of BCN nanosheets as well as their application as a novel catalyst for ODH is reported. Such BCN nanosheets consist of hybridized, randomly distributed domains of h-BN and C phases, where C, B, and N were confirmed to covalent bond in the graphene-like layers. Our studies reveal that BCN exhibits both high activity and selectivity in oxidative dehydrogenation of ethylbenzene to styrene, as well as excellent oxidation resistance. The discovery of such a simple chemical process to synthesize highly active BCN allows the possibility of carbocatalysis to be explored.
Co-reporter:Dr. Yuanxing Fang; Xinchen Wang
Angewandte Chemie 2017 Volume 129(Issue 49) pp:15712-15724
Publication Date(Web):2017/12/04
DOI:10.1002/ange.201707824
AbstractMetallfreie Katalysatoren haben spezifische Vorteile gegenüber Metall- und Metalloxidkatalysatoren, z. B. sind sie kostengünstiger, zuverlässiger und nachhaltiger. Unter den Nichtmetallverbindungen für die Katalyse wurden Bor-haltige Verbindungen mit einigen einzigartigen Eigenschaften entwickelt. In diesem Kurzaufsatz werden die aktuellen Entwicklungen auf dem Gebiet Bor-haltiger, metallfreier Katalysatoren vorgestellt, darunter binäre und ternäre Bor-haltige Katalysatormaterialien. Außerdem werden die drei Hauptanwendungen in der Katalyse angesprochen, nämlich die Elektrokatalyse, Thermokatalyse und Photokatalyse. Hierbei wird die jeweilige Rolle von Bor für die spezifische Katalyseanwendung vertieft diskutiert. Bor-haltige Verbindungen könnten das Gebiet der metallfreien Katalyse zukünftig wesentlich beeinflussen.
Co-reporter:Fangsong Guo;Dr. Pengju Yang;Zhiming Pan;Xu-Ning Cao; Zailai Xie; Xinchen Wang
Angewandte Chemie 2017 Volume 129(Issue 28) pp:8343-8347
Publication Date(Web):2017/07/03
DOI:10.1002/ange.201703789
AbstractCarbon-based catalysts have demonstrated great potential for the aerobic oxidative dehydrogenation reaction (ODH). However, its widespread application is retarded by the unavoidable deactivation owing to the appearance of coking or combustion under ODH conditions. The synthesis and characterization of porous structure of BCN nanosheets as well as their application as a novel catalyst for ODH is reported. Such BCN nanosheets consist of hybridized, randomly distributed domains of h-BN and C phases, where C, B, and N were confirmed to covalent bond in the graphene-like layers. Our studies reveal that BCN exhibits both high activity and selectivity in oxidative dehydrogenation of ethylbenzene to styrene, as well as excellent oxidation resistance. The discovery of such a simple chemical process to synthesize highly active BCN allows the possibility of carbocatalysis to be explored.
Co-reporter:Honghui Ou;Lihua Lin;Yun Zheng;Pengju Yang;Yuanxing Fang
Advanced Materials 2017 Volume 29(Issue 22) pp:
Publication Date(Web):2017/06/01
DOI:10.1002/adma.201700008
Tri-s-triazine-based crystalline carbon nitride nanosheets (CCNNSs) have been successfully extracted via a conventional and cost-effective sonication–centrifugation process. These CCNNSs possess a highly defined and unambiguous structure with minimal thickness, large aspect ratios, homogeneous tri-s-triazine-based units, and high crystallinity. These tri-s-triazine-based CCNNSs show significantly enhanced photocatalytic hydrogen generation activity under visible light than g-C3N4, poly (triazine imide)/Li+ Cl–, and bulk tri-s-triazine-based crystalline carbon nitrides. A highly apparent quantum efficiency of 8.57% at 420 nm for hydrogen production from aqueous methanol feedstock can be achieved from tri-s-triazine-based CCNNSs, exceeding most of the reported carbon nitride nanosheets. Benefiting from the inherent structure of 2D crystals, the ultrathin tri-s-triazine-based CCNNSs provide a broad range of application prospects in the fields of bioimaging, and energy storage and conversion.
Co-reporter:Zuoli He, Chuhyung Kim, Lihua Lin, Tae Hwa Jeon, Sen Lin, Xinchen Wang, Wonyong Choi
Nano Energy 2017 Volume 42(Volume 42) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.nanoen.2017.10.043
•In this work, we introduced a new kind of 2D heterojunction created by loading CN on h-BN nanosheets.•The effects of CN loading on the surface chemistry and photocatalytic activities were systematically investigated.•Photocatalytic H2 and H2O2 production activities of hybrid CBN-x samples were proven to be enhanced.•We carried out first-principle calculations which revealed the unique physical features of CN/BN heterostructures.Many recent advances in creating heterostructures based on 2D materials have opened new possibilities in catalysis. This study prepared a new 2D hybrid photocatalyst (CBN-x) consisting of CN and h-BN using low-cost precursors (urea and boric acid). The effects of CN loading on the structure, surface chemistry and photocatalytic activities were systematically investigated. The photocatalytic activities of CBN-x samples were tested for the production of H2 and H2O2, which demonstrated markedly enhanced activities without the need of noble metal co-catalysts. However, CBN-x activities for the photocatalytic oxidation of organic compound were not better than that of h-BN. Loading CN on h-BN sheets, C 2p and N 2p orbitals from CN introduce new valence and conduction band edges, which gradually narrowed the bandgap and enhanced light absorption efficiency of the hybrid photocatalysts. In such metal-free systems, electrons generated in CN transfer to h-BN, while photogenerated holes on h-BN transfer to CN, which enhances the charge separation through the heterojunction interface (CN/BN). Therefore, increasing the CN loading enhances the overall efficiency of photocatalysis until excessive loading of CN covers the active sites on h-BN.Download high-res image (314KB)Download full-size image
Co-reporter:Guigang Zhang, Zhi-An Lan, Lihua Lin, Sen Lin and Xinchen Wang
Chemical Science 2016 vol. 7(Issue 5) pp:3062-3066
Publication Date(Web):27 Jan 2016
DOI:10.1039/C5SC04572J
We report the direct splitting of pure water by light-excited graphitic carbon nitride (g-C3N4) modified with Pt, PtOx, and CoOx as redox cocatalysts, while pure g-C3N4 is virtually inactive for overall water splitting by photocatalysis. The novelty is in the selective creation of both H2 and O2 cocatalysts on surface active sites of g-C3N4via photodeposition triggering the splitting of water for the simultaneous evolution of H2 and O2 gases in a stoichiometric ratio of 2:1, irradiated with light, without using any sacrificial reagents. The photocatalyst was stable for 510 hours of reaction.
Co-reporter:Lihua Lin, Honghui Ou, Yongfan Zhang, and Xinchen Wang
ACS Catalysis 2016 Volume 6(Issue 6) pp:3921
Publication Date(Web):May 11, 2016
DOI:10.1021/acscatal.6b00922
Graphitic carbon nitride (g-CN) is an emerging metal-free photocatalyst for solar energy conversion via water splitting and CO2 fixation. Herein, we used preheated melamine as a starting material in combination with the salt melt method to synthesize a crystalline tri-s-triazine-based g-CN. The as-obtained sample exhibited high stability and photocatalytic activity toward hydrogen and oxygen production from water splitting. In addition, by adding phosphate to mimic natural photosynthetic environment, the apparent quantum yield (AQY) for the hydrogen production reached 50.7% at 405 nm, which is the highest value ever reported for conjugated carbon nitride polymers in hydrogen evolution photocatalysis. The results of this study demonstrate that crystalline covalent tri-s-triazine frameworks hold great promise for solar energy applications.Keywords: carbon nitride; crystalline; photocatalysis; salt melt; water splitting
Co-reporter:Guigang Zhang, Shaohong Zang, Lihua Lin, Zhi-An Lan, Guosheng Li, and Xinchen Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 3) pp:2287
Publication Date(Web):January 5, 2016
DOI:10.1021/acsami.5b11167
The rational cooperation of sustainable catalysts with suitable light-harvesting semiconductors to fabricate photosynthetic device/machinery has been regarded as an ideal technique to alleviate the current worldwide energy and environmental issues. Cobalt based species (e.g., Co-Pi, Co3O4, and Co-cubene) have attracted particular attentions because they are earth-abundant, cost-acceptable, and more importantly, it shows comparable water oxidation activities to the noble metal based catalysts (e.g., RuO2, IrO2). In this contribution, we compared two general cocatalysts modification strategies, based on the surface depositing and bulk doping of ultrafine cobalt species into the sustainable graphitic carbon nitride (g-C3N4) polymer networks for oxygenic photosynthesis by splitting water into oxygen, electrons, and protons. The chemical backbone of g-C3N4 does not alter after both engineering modifications; however, in comparison with the bulk doping, the optical and electronic properties of the surface depositing samples are efficiently promoted, and the photocatalytic water oxidation activities are increased owing to much more exposed active sites, reduced overpotential for oxygen evolution and the accelerated interface charge mobility. This paper underlines the advantage of surface engineering to establish efficient advanced polymeric composites for water oxidation, and it opens new insights into the architectural design of binary hybrid photocatalysts with high reactivity and further utilizations in the fields of energy and environment.Keywords: cobalt species; graphitic carbon nitride; oxygenic photosynthesis; photocatalysis; sustainable energy production
Co-reporter:Sibo Wang ; Xinchen Wang
Angewandte Chemie International Edition 2016 Volume 55( Issue 7) pp:2308-2320
Publication Date(Web):
DOI:10.1002/anie.201507145
Abstract
Imidazolium ionic liquids (ILs), imidazolylidene N-heterocyclic carbenes (NHCs), and zeolitic imidazolate frameworks (ZIFs) are imidazolate motifs which have been extensively investigated for CO2 adsorption and conversion applications. Summarized in this minireview is the recent progress in the capture, activation, and photochemical reduction of CO2 with these three imidazolate building blocks, from homogeneous molecular entities (ILs and NHCs) to heterogeneous crystalline scaffolds (ZIFs). The developments and existing shortcomings of the imidazolate motifs for their use in CO2 utilizations is assessed, with more of focus on CO2 photoredox catalysis. The opportunities and challenges of imidazolate scaffolds for future advancement of CO2 photochemical conversion for artificial photosynthesis are discussed.
Co-reporter:Zhiping Song;Tianran Lin;Lihua Lin;Dr. Sen Lin; Fengfu Fu; Xinchen Wang; Liangqia Guo
Angewandte Chemie International Edition 2016 Volume 55( Issue 8) pp:2773-2777
Publication Date(Web):
DOI:10.1002/anie.201510945
Abstract
Stimuli-responsive photoluminescent (PL) materials have been widely used as fluorescent ink for data security applications. However, traditional fluorescent inks are limited in maintaining the secrecy of information because the inks are usually visible by naked eyes either under ambient light or UV-light illumination. Here, we introduced metal-free water-soluble graphitic carbon nitride quantum dots (g-CNQDs) as invisible security ink for information coding, encryption, and decryption. The information written by the g-CNQDs is invisible in ambient light and UV light, but it can be readable by a fluorescence microplate reader. Moreover, the information can be encrypted and decrypted by using oxalic acid and sodium bicarbonate as encryption reagent and decryption reagent, respectively. Our findings provide new opportunities for high-level information coding and protection by using water-soluble g-CNQDs as invisible security ink.
Co-reporter:Sibo Wang ; Xinchen Wang
Angewandte Chemie 2016 Volume 128( Issue 7) pp:2352-2364
Publication Date(Web):
DOI:10.1002/ange.201507145
Abstract
Ionische Flüssigkeiten (ILs, ionic liquids) auf Imidazoliumbasis, N-heterocyclische Imidazolylidencarbene (NHCs) und zeolithische Imidazolatgerüste (ZIFs, zeolitic imidazolate frameworks) sind Imidazolat-Strukturmotive, die für Anwendungen in der Abscheidung und Umwandlung von CO2 umfassend untersucht wurden. In diesem Kurzaufsatz werden die jüngsten Fortschritte bei der Abscheidung, Aktivierung und photochemischen Reduktion von CO2 mit diesen drei Imidazolat-Bausteinen – von homogenen molekularen Einheiten (ILs und NHCs) bis zu heterogenen kristallinen Gerüsten (ZIFs) – zusammengefasst. Die erreichten Entwicklungen und verbleibenden Hindernisse bei der Anwendung von Imidazolat-Strukturmotiven in der CO2-Nutzung werden beurteilt, wobei der Schwerpunkt auf der CO2-Photoredoxkatalyse liegt.
Co-reporter:Zhiping Song;Tianran Lin;Lihua Lin;Dr. Sen Lin; Fengfu Fu; Xinchen Wang; Liangqia Guo
Angewandte Chemie 2016 Volume 128( Issue 8) pp:2823-2827
Publication Date(Web):
DOI:10.1002/ange.201510945
Abstract
Stimuli-responsive photoluminescent (PL) materials have been widely used as fluorescent ink for data security applications. However, traditional fluorescent inks are limited in maintaining the secrecy of information because the inks are usually visible by naked eyes either under ambient light or UV-light illumination. Here, we introduced metal-free water-soluble graphitic carbon nitride quantum dots (g-CNQDs) as invisible security ink for information coding, encryption, and decryption. The information written by the g-CNQDs is invisible in ambient light and UV light, but it can be readable by a fluorescence microplate reader. Moreover, the information can be encrypted and decrypted by using oxalic acid and sodium bicarbonate as encryption reagent and decryption reagent, respectively. Our findings provide new opportunities for high-level information coding and protection by using water-soluble g-CNQDs as invisible security ink.
Co-reporter:Jinshui Zhang, Yan Chen and Xinchen Wang
Energy & Environmental Science 2015 vol. 8(Issue 11) pp:3092-3108
Publication Date(Web):30 Jul 2015
DOI:10.1039/C5EE01895A
The development of new layered materials has experienced an evolution from graphene to metal oxide and metal chalcogenide nanosheets, and more recently to two-dimensional (2D) covalent organic frameworks, such as conjugated carbon nitride nanosheets (CNNs) with a spectral gap in the band structure. The anisotropic 2D geometric morphology, together with the aromatic π-conjugated framework, endows polymeric CNNs with unique properties, such as an enlarged surface area with a highly opened-up flat structure, reduced thickness with enhanced electron mobility and with intrinsic semiconductive features, which support their attractive bandgap- and surface-engineered applications ranging from energy-related topics to other new emerging fields. In this review, recent research advances in the establishment of two synthetic strategies for CNNs are firstly overviewed, namely, the top-down delamination of graphitic carbon nitride (CN) solids and the bottom-up assembly of molecular building blocks in a 2D manner. Efficient approaches aimed at advancing CNNs for target-specific applications, including hybridizing, doping, sensitization, copolymerization and nanorefinement, are also described as possible solutions.
Co-reporter:Guigang Zhang, Shaohong Zang, and Xinchen Wang
ACS Catalysis 2015 Volume 5(Issue 2) pp:941
Publication Date(Web):December 22, 2014
DOI:10.1021/cs502002u
Here we report a facile impregnation synthesis of layered Co(OH)2 deposited with g-C3N4 while the pH value is adjusted by using ammonia solution for photocatalytic water oxidation with UV–vis and visible light illumination. This surface modification not only accelerates the interface transfer rate of charge carriers but also reduces the excessive energy barrier for O–O formation, thus leading to enhanced reaction kinetics for photocatalytic water oxidation. The optimum oxygen evolution rates (OERs) of the Co(OH)2/g-C3N4 sample reached 27.4 and 7.1 μmol h–1 under UV–vis (λ >300 nm) and visible light (λ >420 nm) irradiation, which are 5.5 and 7 times faster than those for pristine g-C3N4, respectively. These results underline the possibility for the development of effective, robust, and earth-abundant WOCs for the promotion of water-splitting photocatalysis by sustainable g-C3N4 polymer photocatalysts.Keywords: cobalt hydroxide; graphitic carbon nitride; heterojunction; photocatalysis; water oxidation
Co-reporter:Dandan Zheng, Caijing Huang and Xinchen Wang
Nanoscale 2015 vol. 7(Issue 2) pp:465-470
Publication Date(Web):20 Nov 2014
DOI:10.1039/C4NR06011C
Hollow-structured g-C3N4 polymers with a high thermal stability up to 550 °C and an enhanced photocatalytic activity have been developed by post-annealing treatment, which effectively modifies the textural, crystal, and electronic properties of the g-C3N4 semiconductors without extra chemical assistance. This is a unique example of thermally and chemically stable conjugated polymers with hollow nanostructures and optoelectronic properties, promising the development of functional hollow g-C3N4 nanocomposites by chemical modifications like doping, surface grafting, and coupling with other inorganic/polymeric semiconductors with the aid of thermal treatment at high temperatures.
Co-reporter:Guigang Zhang, Shaohong Zang, Zhi-An Lan, Caijin Huang, Guosheng Li and Xinchen Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 35) pp:17946-17950
Publication Date(Web):04 Aug 2015
DOI:10.1039/C5TA04767F
Cobalt selenide has been developed as an effective cocatalyst to decorate visible light photocatalysts, including WO3, BiVO4 and g-C3N4, establishing intense surface contact with substrates for the photocatalytic water oxidation reaction. Compared with CoOx and CoSx, CoSe2 is superior for improving the photocatalytic water oxidation activity due to the lower anionic electronegativity, which leads to dense adhesion and enables fast interfacial charge transfer for the water oxidation reaction.
Co-reporter:Sibo Wang, Zhengxin Ding and Xinchen Wang
Chemical Communications 2015 vol. 51(Issue 8) pp:1517-1519
Publication Date(Web):25 Nov 2014
DOI:10.1039/C4CC07225A
Spinel ZnCo2O4 nanostructures have shown great opportunities in energy related areas. However, the applications of ZnCo2O4 for the conversion of CO2 are much less reported. Herein, we present the use of mesoporous ZnCo2O4 nanorods as efficient and high stable cocatalysts for the photochemical reduction of CO2 under mild reaction conditions.
Co-reporter:Dandan Zheng, Chenyang Pang and Xinchen Wang
Chemical Communications 2015 vol. 51(Issue 98) pp:17467-17470
Publication Date(Web):08 Oct 2015
DOI:10.1039/C5CC07867A
A ternary photocatalyst has been successfully constructed through the integration of Au, CdS and hollow carbon nitride nanospheres (HCNS), where Au nanoparticles were designed to shuttle interparticle transfer of charge carriers between CdS and HCNS photosensitizers to establish two-photon (Z-scheme) photocatalytic tandem systems for solar fuel production. The solid-state CdS–Au–HCNS Z-scheme nanocomposites were efficient for H2 evolution (with a quantum yield of 8.7% at 420 nm) and CO2 reduction catalysis with visible light irradiation. This work further proves the feasibility of employing hollow conjugated polymer photocatalysts in the function-led design of artificial Z-type photosynthetic machinery on soft material interfaces.
Co-reporter:Dandan Zheng, Chenyang Pang, Yuxing Liu and Xinchen Wang
Chemical Communications 2015 vol. 51(Issue 47) pp:9706-9709
Publication Date(Web):06 May 2015
DOI:10.1039/C5CC03143E
Incorporation of aromatic motifs into the nanosized shells of hollow carbon nitride nanospheres has been reported to develop functional photosynthetic structures for solar energy application. This modification results in an extended π-conjugation system, red-shift of the optical absorption, and an improved charge separation in the shell, while still retaining the unique hollow polymeric nanoarchitectures. This strategy enables the tuning of the semiconductor properties of the shell substance in the hollow carbon nitride nanostructures to generate the redox species to enhance photocatalytic activity for hydrogen evolution using visible light.
Co-reporter:Sibo Wang, Yidong Hou, and Xinchen Wang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 7) pp:4327
Publication Date(Web):February 3, 2015
DOI:10.1021/am508766s
The synthesis of uniform MnCo2O4 microspheres and their cooperation with a visible light harvester to achieve efficient photocatalytic CO2 reduction under ambient conditions are reported here. The MnCo2O4 materials were prepared by a facile two-step solvothermal-calcination method and were characterized by XRD, SEM, TEM, EDX, XPS, elemental mapping, and N2 adsorption measurements. By using the MnCo2O4 microspheres as a heterogeneous cocatalyst, the photocatalytic performance of the CO2-to-CO conversion catalysis was remarkably enhanced, and no decrease in the promotional effect of the cocatalyst was observed after repeatedly operating the reaction for six cycles. 13CO2 isotope tracer experiments verified that the CO product originated from the CO2 reactant. The effect of synthetic conditions and various reaction parameters on the photocatalytic activity of the system were investigated and optimized. The stability of the MnCo2O4 cocatalyst in the CO2 reduction system was confirmed by several techniques. Moreover, a possible mechanism for MnCo2O4-cocatalyzed CO2 photoreduction catalysis is proposed.Keywords: artificial photosynthesis; CO2 reduction; cooperative catalysis; heterogeneous photocatalysis; MnCo2O4 microspheres; ternary metal oxide
Co-reporter:Guigang Zhang;Guosheng Li ; Xinchen Wang
ChemCatChem 2015 Volume 7( Issue 18) pp:2864-2870
Publication Date(Web):
DOI:10.1002/cctc.201500069
Abstract
Ni/NiO core–shell cocatalysts have been prepared on the surface of graphitic carbon nitride by a facile in situ immersion strategy to promote photocatalytic H2 evolution activity under the light irradiation of the conjugated polymer. The physicochemical properties of the as-prepared hybridized materials were characterized by several techniques, which include XRD, UV-Raman spectroscopy, diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy, to investigate the composition, texture, surface properties, and optical properties of the samples. In comparison with an unmodified carbon nitride polymer, the Ni/NiO-decorated sample shows an increased photocatalytic H2 evolution rate and good durability because of the promoted surface kinetics that increase the charge-transfer rate and reduce the overpotential for H2 evolution dramatically.
Co-reporter:Guigang Zhang;Zhi-An Lan ;Dr. Xinchen Wang
ChemCatChem 2015 Volume 7( Issue 9) pp:1422-1423
Publication Date(Web):
DOI:10.1002/cctc.201500133
Co-reporter:Dr. Jinshui Zhang;Mingwen Zhang;Lihua Lin ; Xinchen Wang
Angewandte Chemie International Edition 2015 Volume 54( Issue 21) pp:6297-6301
Publication Date(Web):
DOI:10.1002/anie.201501001
Abstract
The chemical protonation of graphitic carbon nitride (CN) solids with strong oxidizing acids, for example HNO3, is demonstrated as an efficient pathway for the sol processing of a stable CN colloidal suspension, which can be translated into thin films by dip/disperse-coating techniques. The unique features of CN colloids, such as the polymeric matrix and the reversible hydrogen bonding, result in the thin-film electrodes derived from the sol solution exhibiting a high mechanical stability with improved conductivity for charge transport, and thus show a remarkably enhanced photo-electrochemical performance. The polymer system can in principle be broadly tuned by hybridization with desired functionalities, thus paving the way for the application of CN for specific tasks, as exemplified here by coupling with carbon nanotubes.
Co-reporter:Yun Zheng;Lihua Lin;Bo Wang ; Xinchen Wang
Angewandte Chemie 2015 Volume 127( Issue 44) pp:13060-13077
Publication Date(Web):
DOI:10.1002/ange.201501788
Abstract
Graphitisches Kohlenstoffnitrid (g-C3N4) ist ein vielversprechendes zweidimensionales konjugiertes Polymer, das als kostengünstiger, robuster, metallfreier und im sichtbaren Spektralbereich aktiver Photokatalysator für die Umwandlung von Sonnenenergie verwendet wird. Hauptthema dieses Aufsatzes sind die neuesten Entwicklungen bei g-C3N4-Photokatalysatoren für die Wasserspaltung. Anwendungen für CO2-Umwandlung, organische Synthese und Schadstoffabbau werden ebenfalls diskutiert. Außerdem werden Methoden zur Anpassung der elektronischen Struktur, Nanostruktur, Kristallstruktur und Heterostruktur von g-C3N4 sowie die entsprechenden Korrelationen zwischen Struktur und Leistung vorgestellt. Es erfolgt ein Ausblick auf die Herausforderungen und Chancen bei der künftigen Erforschung von g-C3N4-Photokatalysatoren. Dieser Aufsatz ist als eine Werbung für die Nutzung von g-C3N4-Materialien auf den Gebieten der Photokatalyse, der Energieumwandlung, des Schadstoffabbaus und für Sensoren gedacht.
Co-reporter:Dr. Jinshui Zhang;Mingwen Zhang;Lihua Lin ; Xinchen Wang
Angewandte Chemie 2015 Volume 127( Issue 21) pp:6395-6399
Publication Date(Web):
DOI:10.1002/ange.201501001
Abstract
The chemical protonation of graphitic carbon nitride (CN) solids with strong oxidizing acids, for example HNO3, is demonstrated as an efficient pathway for the sol processing of a stable CN colloidal suspension, which can be translated into thin films by dip/disperse-coating techniques. The unique features of CN colloids, such as the polymeric matrix and the reversible hydrogen bonding, result in the thin-film electrodes derived from the sol solution exhibiting a high mechanical stability with improved conductivity for charge transport, and thus show a remarkably enhanced photo-electrochemical performance. The polymer system can in principle be broadly tuned by hybridization with desired functionalities, thus paving the way for the application of CN for specific tasks, as exemplified here by coupling with carbon nanotubes.
Co-reporter:Dr. Jinshui Zhang ; Xinchen Wang
Angewandte Chemie 2015 Volume 127( Issue 25) pp:7336-7338
Publication Date(Web):
DOI:10.1002/ange.201502659
Co-reporter:Yun Zheng;Lihua Lin;Bo Wang ; Xinchen Wang
Angewandte Chemie International Edition 2015 Volume 54( Issue 44) pp:12868-12884
Publication Date(Web):
DOI:10.1002/anie.201501788
Abstract
As a promising two-dimensional conjugated polymer, graphitic carbon nitride (g-C3N4) has been utilized as a low-cost, robust, metal-free, and visible-light-active photocatalyst in the field of solar energy conversion. This Review mainly describes the latest advances in g-C3N4 photocatalysts for water splitting. Their application in CO2 conversion, organosynthesis, and environmental purification is also briefly discussed. The methods to modify the electronic structure, nanostructure, crystal structure, and heterostructure of g-C3N4, together with correlations between its structure and performance are illustrated. Perspectives on the challenges and opportunities for the future exploration of g-C3N4 photocatalysts are provided. This Review will promote the utilization of g-C3N4 materials in the fields of photocatalysis, energy conversion, environmental remediation, and sensors.
Co-reporter:Mingwen Zhang;Zhishan Luo;Min Zhou;Caijin Huang
Science China Materials 2015 Volume 58( Issue 11) pp:867-876
Publication Date(Web):2015/11/01
DOI:10.1007/s40843-015-0100-z
A hexagonal boron carbon nitride (h-BCN) semiconductor was applied to intercalate cobalt ions to catalyze oxygen evolution reaction (OER) with light illumination, without using noble metals. The h-BCN with high specific surface area showed a strong chemical affinity towards metal ions due to the “lop-sided” densities characteristic of ionic B–N bonding, enabling the creation of metal/h-BCN hybrid layered structures with unique properties. As exemplified here by Co/h-BCN for water oxidation catalysis, after intercalating cobalt ions in the h-BCN host, the photocatalytic activity of the resultant layered hybrid is optimized due to their synergic catalysis that promotes charge separation and lowers reaction barriers. This finding promises a new nobel-metal-free nanocompsite using cost-acceptable and earth-abundant sust ances for photocatalytic OER, and enables the facile design of duel catalytic cascades by merging transition metal catalysis with h-BCN (photo)catalysis for energy and sustainability.本文利用六方相硼氮碳(h-BCN)半导体光催化剂吸附钴离子, 构筑不含任何贵金属成分的光催化体系, 在可见光照射下, 实现水的催化氧化生成氧气反应. h-BCN半导体材料由于B–N离子键的“lop-sided”效应, 对金属离子具有很强的化学亲和性, 利用此性质并结合其高比表面积的特性, 制备出了一系列具有特殊性能的金属/h-BCN杂化层状结构. 研究结果表明, 在钴离子镶嵌的h-BCN(Co/h-BCN)杂化材料中, 金属和载体之间的协同作用能有效促进光生载流子分离、降低反应活化能, 进而提高光催化氧化水产氧性能. 本文展示了利用廉价和地球高丰度元素构筑不含贵金属成份的纳米层状复合材料, 有望将过渡金属催化和h-BCN光催化耦合, 实现面向可持续能源转换的协同催化过程.
Co-reporter:Dr. Jinshui Zhang ; Xinchen Wang
Angewandte Chemie International Edition 2015 Volume 54( Issue 25) pp:7230-7232
Publication Date(Web):
DOI:10.1002/anie.201502659
Co-reporter:Huiquan Li;Yuxing Liu;Xing Gao;Cong Fu; Xinchen Wang
ChemSusChem 2015 Volume 8( Issue 7) pp:1189-1196
Publication Date(Web):
DOI:10.1002/cssc.201500024
Abstract
The semiconductor heterojunction has been an effective architecture to enhance photocatalytic activity by promoting photogenerated charge separation. Here, graphitic carbon nitride (CN) and B-modified graphitic carbon nitride (CNB) composite semiconductors were fabricated by a facile calcination process using cheap, sustainable, and easily available sodium tetraphenylboron and urea as precursors. The synthetic CN-CNB-25 semiconductor with a suitable CNB content showed the highest visible-light activity. Its degradation ratio for methyl orange and phenol was more than twice that of CN and CNB and its H2 evolution rate was ∼3.4 and ∼1.8 times higher than that of CN and CNB, respectively. It also displayed excellent stability and reusability. The enhanced activity of CN-CNB-25 was attributed predominantly to the efficient separation of photoinduced electrons and holes. This paper describes a visible-light-responsive CN composite semiconductor with great potential in environmental and energy applications.
Co-reporter:Huanli Wang, Lisha Zhang, Zhigang Chen, Junqing Hu, Shijie Li, Zhaohui Wang, Jianshe Liu and Xinchen Wang
Chemical Society Reviews 2014 vol. 43(Issue 15) pp:5234-5244
Publication Date(Web):20 May 2014
DOI:10.1039/C4CS00126E
Semiconductor-mediated photocatalysis has received tremendous attention as it holds great promise to address the worldwide energy and environmental issues. To overcome the serious drawbacks of fast charge recombination and the limited visible-light absorption of semiconductor photocatalysts, many strategies have been developed in the past few decades and the most widely used one is to develop photocatalytic heterojunctions. This review attempts to summarize the recent progress in the rational design and fabrication of heterojunction photocatalysts, such as the semiconductor–semiconductor heterojunction, the semiconductor–metal heterojunction, the semiconductor–carbon heterojunction and the multicomponent heterojunction. The photocatalytic properties of the four junction systems are also discussed in relation to the environmental and energy applications, such as degradation of pollutants, hydrogen generation and photocatalytic disinfection. This tutorial review ends with a summary and some perspectives on the challenges and new directions in this exciting and still emerging area of research.
Co-reporter:Mingwen Zhang and Xinchen Wang
Energy & Environmental Science 2014 vol. 7(Issue 6) pp:1902-1906
Publication Date(Web):25 Feb 2014
DOI:10.1039/C3EE44189J
To counteract the unwanted quantum confinement effect and less efficient electron screening in low dimensional carbon nitride, fusion of aromatic motifs into conjugated carbon nitride nanosheets has been developed. This results in a red-shift of the optical absorption and an improved charge separation in the polymer semiconductor, establishing a quantum efficiency of 8.8% at 420 nm for H2 generation.
Co-reporter:Jinshui Zhang;Mingwen Zhang;Can Yang
Advanced Materials 2014 Volume 26( Issue 24) pp:4121-4126
Publication Date(Web):
DOI:10.1002/adma.201400573
Co-reporter:Guigang Zhang;Mingwen Zhang;Xinxin Ye;Xiaoqing Qiu;Sen Lin
Advanced Materials 2014 Volume 26( Issue 5) pp:805-809
Publication Date(Web):
DOI:10.1002/adma.201303611
Co-reporter:Sibo Wang, Yidong Hou, Sen Lin and Xinchen Wang
Nanoscale 2014 vol. 6(Issue 17) pp:9930-9934
Publication Date(Web):26 Jun 2014
DOI:10.1039/C4NR02399D
The search for efficient water oxidation catalysts (WOCs) is of paramount importance in energy and environmental fields, but there exists no good non-noble catalyst that works under acidic and alkaline conditions. Intensive investigations have recently focused on cobalt based complex/solid catalysts. Here, we have introduced a new type of cobalt-based WOC made of metal–organic frameworks where the redox function of cobalt centres was modified by imidazolate linkers for facilitating the proton transfer process. This cobalt-containing zeolitic imidazolate framework (Co-ZIF-9) has been demonstrated for the first time to electrocatalyze the oxygen evolution reaction in a wide pH range. The catalyst was found by theoretical calculation to be capable of activating the water molecule via binding the OH-group to the metal sites with low activation barriers, while the eliminated proton was accepted by the nearby benzimidazolate motifs. This allows Co-ZIF-9 to work effectively for the electrochemical oxygen-evolution reaction.
Co-reporter:Baihua Long, Jinliang Lin and Xinchen Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 9) pp:2942-2951
Publication Date(Web):2013/11/22
DOI:10.1039/C3TA14339B
A cheap and easily-available organosulfur compound, guanidine thiocyanate, has been used to synthesize graphitic carbon nitride (g-C3N4) by a thermally-induced desulfurization and polymerization of the precursor. Photocatalytic activity experiments demonstrated that the g-C3N4 synthesized from guanidine thiocyanate exhibited a much higher H2 evolution rate than the reference sample prepared from dicyanamide. Further improvement in the activity was achieved by optimization of the condensation temperature. Based on X-ray photoelectron spectroscopy analysis, the samples synthesized at a high temperature of 700 °C feature a high crystallinity and a low density of surface defects, with an enhanced optical absorbance extending to the visible light region. As a result, the sample prepared at 700 °C has been found to be 7 times more reactive towards photocatalytic hydrogen evolution than the sample polymerized at the normal temperature of 550 °C. Other guanidine halides have also been applied to synthesize g-C3N4 materials, and the structure and activity of the resultant g-C3N4 were compared to the carbon nitride polymer from guanidine thiocyanate.
Co-reporter:Jianhui Huang, Wingkei Ho and Xinchen Wang
Chemical Communications 2014 vol. 50(Issue 33) pp:4338-4340
Publication Date(Web):04 Mar 2014
DOI:10.1039/C3CC48374F
Covalent carbon nitride polymers were applied as metal-free robust catalysts for the inactivation of Escherichia coli K-12 (E. coli), a common Gram-negative bacterium, under visible light illumination. The results demonstrated that the creation of antibacterial function on the surface of conjugated polymers has now become possible.
Co-reporter:Jinliang Lin, Zhiming Pan, and Xinchen Wang
ACS Sustainable Chemistry & Engineering 2014 Volume 2(Issue 3) pp:353
Publication Date(Web):December 1, 2013
DOI:10.1021/sc4004295
The combination of cobalt redox catalysis and carbon nitride photocatalysis to construct a cascade photoreaction system has been developed for the deoxygenative reduction of CO2 to CO with visible light. The graphitic carbon nitride has been demonstrated to function both as a capture/activation substrate of CO2 and a photocatalyst, whereas the introduced cobalt species act as reductive and oxidative promoters to accelerate charge-carrier separation and transfer kinetics. This hybrid photosystem contains inexpensive substances that synergetically catalyze CO2-to-CO conversion at mild conditions, with a high stability of catalysts. The optimization in the surface and texture structures as well as reaction conditions has been demonstrated. The results represent an important step toward artificial photosynthesis by using cost-acceptable materials.Keywords: Carbon nitride; CO; CO2; Cobalt; Photocatalysis
Co-reporter:Sibo Wang, Jinliang Lin and Xinchen Wang
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 28) pp:14656-14660
Publication Date(Web):02 Jun 2014
DOI:10.1039/C4CP02173H
A noble-metal-free system for photochemical reduction of CO2 has been developed by integrating graphitic carbon nitride (g-C3N4) with a cobalt-containing zeolitic imidazolate framework (Co-ZIF-9). g-C3N4 acts as a semiconductor photocatalyst, whereas Co-ZIF-9 is a cocatalyst that facilitates the capture/concentration of CO2 and promotes light-induced charge separation. The two materials cooperate efficiently to catalyze CO2-to-CO conversion upon visible light illumination under mild reaction conditions. A 13C-labelled isotropic experiment proved that CO2 is the carbon source of the produced CO. Even without noble metals, the system still achieved an apparent quantum yield of 0.9 percent. The system displayed high photocatalytic stability, without noticeable alterations in the chemical and crystal structures of g-C3N4 and Co-ZIF-9 after the reaction.
Co-reporter:Xiangju Ye;Yun Zheng
Chinese Journal of Chemistry 2014 Volume 32( Issue 6) pp:498-506
Publication Date(Web):
DOI:10.1002/cjoc.201400229
Abstract
A polymeric Fc-CO-NH-C3N4 (Fc-CN) material was synthesized by amidation reaction of ferrocenecarboxylic acid (Fc-COOH) with NH2 groups on the surface of mesoporous graphitic carbon nitride (MCN). The properties of the as-synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, UV-Vis diffuse reflectance spectra, N2 adsorption-desorption isotherm, photoluminescence spectroscopy, transmission electron microscopy, electron paramagnetic resonance, (photo)electrochemical measurement and X-ray photoelectron spectroscopy. The resultant catalysts were investigated as heterogeneous catalysts for the selective oxidation of benzene to phenol using H2O2 as a green oxidant under visible light irradiation. The results reveal that Fc-modified samples can not only extend the visible light absorption, but also accelerate the bulk-to-surface charge transfer and separation via surface dyadic structures, both of which are favorable for phenol production from benzene photocatalytic hydroxylation with H2O2. Under the optimal conditions, up to 16.9 % phenol yield (based on benzene) is obtained by Fc-CN/1.5-5 sample, and the corresponding Fe content is about 0.64 wt%. Furthermore, after the second run, no significant decrease of the activity (in term of TOF) and the selectivity is found in Fc-CN/1.0-5 sample. Combined with the experimental results and Fenton-chemistry, a possible photocatalytic reaction mechanism on the hydroxylation of benzene to phenol at neutral medium with visible light is proposed.
Co-reporter:Sibo Wang;Wangshu Yao;Jinliang Lin; Zhengxin Ding ; Xinchen Wang
Angewandte Chemie International Edition 2014 Volume 53( Issue 4) pp:1034-1038
Publication Date(Web):
DOI:10.1002/anie.201309426
Abstract
Metal–organic frameworks (MOFs) have shown great promise for CO2 capture and storage. However, the operation of chemical redox functions of framework substances and organic CO2-trapping entities which are spatially linked together to catalyze CO2 conversion has had much less attention. Reported herein is a cobalt-containing zeolitic imidazolate framework (Co-ZIF-9) which serves as a robust MOF cocatalyst to reduce CO2 by cooperating with a ruthenium-based photosensitizer. The catalytic turnover number of Co-ZIF-9 was about 450 within 2.5 hours under mild reaction conditions, while still keeping its original reactivity during prolonged operation.
Co-reporter:Sibo Wang;Wangshu Yao;Jinliang Lin; Zhengxin Ding ; Xinchen Wang
Angewandte Chemie International Edition 2014 Volume 53( Issue 4) pp:
Publication Date(Web):
DOI:10.1002/anie.201310957
Co-reporter:Sibo Wang;Wangshu Yao;Jinliang Lin; Zhengxin Ding ; Xinchen Wang
Angewandte Chemie 2014 Volume 126( Issue 4) pp:1052-1056
Publication Date(Web):
DOI:10.1002/ange.201309426
Abstract
Metal–organic frameworks (MOFs) have shown great promise for CO2 capture and storage. However, the operation of chemical redox functions of framework substances and organic CO2-trapping entities which are spatially linked together to catalyze CO2 conversion has had much less attention. Reported herein is a cobalt-containing zeolitic imidazolate framework (Co-ZIF-9) which serves as a robust MOF cocatalyst to reduce CO2 by cooperating with a ruthenium-based photosensitizer. The catalytic turnover number of Co-ZIF-9 was about 450 within 2.5 hours under mild reaction conditions, while still keeping its original reactivity during prolonged operation.
Co-reporter:Sibo Wang;Wangshu Yao;Jinliang Lin; Zhengxin Ding ; Xinchen Wang
Angewandte Chemie 2014 Volume 126( Issue 4) pp:
Publication Date(Web):
DOI:10.1002/ange.201310957
Co-reporter:Yun Zheng;Lihua Lin;Xiangju Ye;Fangsong Guo ; Xinchen Wang
Angewandte Chemie 2014 Volume 126( Issue 44) pp:12120-12124
Publication Date(Web):
DOI:10.1002/ange.201407319
Abstract
Graphitic carbon nitride can be imprinted with a twisted hexagonal rod-like morphology by a nanocasting technique using chiral silicon dioxides as templates. The helical nanoarchitectures promote charge separation and mass transfer of carbon nitride semiconductors, enabling it to act as a more efficient photocatalyst for water splitting and CO2 reduction than the pristine carbon nitride polymer. This is to our knowledge a unique example of chiral graphitic carbon nitride that features both left- and right-handed helical nanostructures and exhibits unique optical activity to circularly polarized light at the semiconductor absorption edge as well as photoredox activity for solar-to-chemical conversion. Such helical nanostructured polymeric semiconductors are envisaged to hold great promise for a range of applications that rely on such semiconductor properties as well as chirality for photocatalysis, asymmetric catalysis, chiral recognition, nanotechnology, and chemical sensing.
Co-reporter:Jinliang Lin;Dr. Yidong Hou;Yun Zheng ; Xinchen Wang
Chemistry – An Asian Journal 2014 Volume 9( Issue 9) pp:2468-2474
Publication Date(Web):
DOI:10.1002/asia.201402303
Abstract
An efficient chemical system for electron generation and transfer is constructed by the integration of an electron mediator ([Co(bpy)3]2+; bpy=2,2′-bipyridine) with semiconductor photocatalysts. The introduction of [Co(bpy)3]2+ remarkably enhances the photocatalytic activity of pristine semiconductor photocatalysts for heterogeneous CO2 conversion; this is attributable to the acceleration of charge separation. Of particular interest is that the excellent photocatalytic activity of heterogeneous catalysts can be developed as a universal photocatalytic CO2 reduction system. The present findings clearly demonstrate that the integration of an electron mediator with semiconductors is a feasible process for the design and development of efficient photochemical systems for CO2 conversion.
Co-reporter:Zhenzhen Lin ; Xinchen Wang
ChemSusChem 2014 Volume 7( Issue 6) pp:1547-1550
Publication Date(Web):
DOI:10.1002/cssc.201400016
Abstract
To allow for simultaneous textural engineering and doping of carbon nitride materials with heteroatoms, urea has been polymerized with an ionic liquid. The role of urea is to create a delamination effect during carbon nitride synthesis, whereas ionic liquid functions as texture modifier as well as B/F dopant source. This will result in the rational fabrication of boron- and fluorine-containing 2D carbon nitride nanosheets with enhanced optical harvesting and charge separation capabilities for hydrogen evolution catalysis using visible light. We believe that the innovative modification strategy developed herein can be coupled with the already known modification tools of 2D carbon nitride, thus further developing a new family of light-harvesting 2D platforms for the efficient and sustained utilization of solar radiation for a variety of advanced applications, including CO2 photofixation, organic photosynthesis, and pollutant controls.
Co-reporter:Yun Zheng;Lihua Lin;Xiangju Ye;Fangsong Guo ; Xinchen Wang
Angewandte Chemie International Edition 2014 Volume 53( Issue 44) pp:11926-11930
Publication Date(Web):
DOI:10.1002/anie.201407319
Abstract
Graphitic carbon nitride can be imprinted with a twisted hexagonal rod-like morphology by a nanocasting technique using chiral silicon dioxides as templates. The helical nanoarchitectures promote charge separation and mass transfer of carbon nitride semiconductors, enabling it to act as a more efficient photocatalyst for water splitting and CO2 reduction than the pristine carbon nitride polymer. This is to our knowledge a unique example of chiral graphitic carbon nitride that features both left- and right-handed helical nanostructures and exhibits unique optical activity to circularly polarized light at the semiconductor absorption edge as well as photoredox activity for solar-to-chemical conversion. Such helical nanostructured polymeric semiconductors are envisaged to hold great promise for a range of applications that rely on such semiconductor properties as well as chirality for photocatalysis, asymmetric catalysis, chiral recognition, nanotechnology, and chemical sensing.
Co-reporter:Yan Chen ; Bo Wang ; Sen Lin ; Yongfan Zhang
The Journal of Physical Chemistry C 2014 Volume 118(Issue 51) pp:29981-29989
Publication Date(Web):November 24, 2014
DOI:10.1021/jp510187c
In semiconductor-mediated photocatalysis, the optical property of semiconductors is a key parameter and closely related to the conversion efficiency of solar energy. However, endeavors in achieving a wide spectral response of semiconductors are still limited in impurity incorporation or using other assistants. Here, we report on a structure-distortion-induced extension in the optical absorption of conjugated polymer semiconductors without relying on any extra species, by taking a typical example of two-dimensional graphitic carbon nitride (g-C3N4) nanosheets. Experimental and theoretical calculation results both identified the close relationship between the band structure and the structural distortion and the amount of the layers, while keeping in-plane fundamental units intact and the connecting mode invariable during the peeling process. Photocatalytic activity was evaluated toward hydrogen evolution over different samples with visible light. The results showed that distorted g-C3N4 exhibited higher activity and its wavelength-dependence activity can be extended to 550 nm with desirable H2 production. This finding offers a new channel for researchers to design a polymer with photocatalytic activity under its extending visible spectrum.
Co-reporter:Xiangju Ye;Yanjuan Cui ; Xinchen Wang
ChemSusChem 2014 Volume 7( Issue 3) pp:738-742
Publication Date(Web):
DOI:10.1002/cssc.201301128
Abstract
Ferrocene moieties were heterogenized onto carbon nitride polymers by a covalent CN linkage bridging the two conjugation systems, enabling the merging of the redox function of ferrocene with carbon nitride photocatalysis to construct a heterogeneous Photo-Fenton system for green organocatalysis at neutral conditions. The synergistic donor–acceptor interaction between the carbon nitride matrix and ferrocene group, improved exciton splitting, and coupled photocatalytic performance allowed the direct synthesis of phenol from benzene in the presence of H2O2 under visible light irradiation. This innovative modification method will offer an avenue to construct functionalized two-dimensional polymers useful also for other green synthesis processes using solar irradiation.
Co-reporter:Jinshui Zhang;Fangsong Guo
Advanced Functional Materials 2013 Volume 23( Issue 23) pp:3008-3014
Publication Date(Web):
DOI:10.1002/adfm.201203287
Abstract
Nanostructured covalent carbon nitride (CN) holds great promise for artificial photosynthesis, but its nanotexturation using templating methods is restricted by the weak binding affinities of neutral silica templates towards basic precursors that are kinetically difficult to diffuse into the nanopores of the templates. This weak affinity leads to an incomplete inclusion of the CN precursors into the nanostructured silica templates, and consequently, yields a defective replica of the parent porous structures. Here, this issue is addressed through the development of an innovative synthetic strategy to facilitate the sufficient inclusion of CN precursors in silica templates, by taking advantage of the surface acidification of silica and sonication-promoted insertion. The ordered mesoporous CN (ompg-CN) fabricated using SBA-15 mesozeolite as the template has been demonstrated to show a better 2D mesoporous hexagonal framework, larger surface area, and higher photocatalytic activity than that synthesized by the traditional method. This innovative strategy can in general be expanded to other silica templates with various nanostructures, enabling the creation of stable polymeric CN nanostructures with maximized material and structure functions.
Co-reporter:Yan Chen, Jinshui Zhang, Mingwen Zhang and Xinchen Wang
Chemical Science 2013 vol. 4(Issue 8) pp:3244-3248
Publication Date(Web):28 May 2013
DOI:10.1039/C3SC51203G
A thiophene motif has been integrated into mesoporous carbon nitride (MCN) to improve the photoactivation of molecular oxygen towards the selective oxidation of alcohols. This modification also extends the photoactive part of the spectrum of MCN by electronic modification of the conjugated system.
Co-reporter:Marek Grzelczak, Jinshui Zhang, Johannes Pfrommer, Jürgen Hartmann, Matthias Driess, Markus Antonietti, and Xinchen Wang
ACS Catalysis 2013 Volume 3(Issue 3) pp:383
Publication Date(Web):January 29, 2013
DOI:10.1021/cs3007523
Splitting of water to hydrogen and oxygen on colloidal catalysts is a promising method for future energy and chemistry cycles. The currently used high-performance oxides containing expensive elements (Ru, Ir) are progressively being replaced by more sustainable ones, such as Co3O4. Although the size of the nanoparticles determines their catalytic performance, the control over the particles’ diameter is often synthetically difficult to achieve. An additional obstacle is the presence of stabilizing agent, an organic molecule that blocks accessible surface-active centers. Herein, we present how precise control over size of the cobalt oxide nanoparticles (Co3O4 NPs), their colloidal stability, and the ligand-free surface affect overall performance of the photocatalytic oxygen evolution. We accordingly correlated the photochemical results with the electrochemical studies, concluding that accessibility of the active species on the particles’ surface is crucial parameter in water oxidation.Keywords: cobalt oxide; nanoparticles; photocatalysis; size control; water oxidation
Co-reporter:Yidong Hou;Anders B. Laursen;Jinshui Zhang;Guigang Zhang;Yongsheng Zhu; Xinchen Wang; Søren Dahl; Ib Chorkendorff
Angewandte Chemie International Edition 2013 Volume 52( Issue 13) pp:3621-3625
Publication Date(Web):
DOI:10.1002/anie.201210294
Co-reporter:Baihua Long; Zhengxin Ding ; Xinchen Wang
ChemSusChem 2013 Volume 6( Issue 11) pp:
Publication Date(Web):
DOI:10.1002/cssc.201301097
Co-reporter:Zhenzhen Lin ; Xinchen Wang
Angewandte Chemie 2013 Volume 125( Issue 6) pp:1779-1782
Publication Date(Web):
DOI:10.1002/ange.201209017
Co-reporter:Zhenzhen Lin ; Xinchen Wang
Angewandte Chemie International Edition 2013 Volume 52( Issue 6) pp:1735-1738
Publication Date(Web):
DOI:10.1002/anie.201209017
Co-reporter:Yidong Hou;Anders B. Laursen;Jinshui Zhang;Guigang Zhang;Yongsheng Zhu; Xinchen Wang; Søren Dahl; Ib Chorkendorff
Angewandte Chemie 2013 Volume 125( Issue 13) pp:3709-3713
Publication Date(Web):
DOI:10.1002/ange.201210294
Co-reporter:Baihua Long; Zhengxin Ding ; Xinchen Wang
ChemSusChem 2013 Volume 6( Issue 11) pp:2074-2078
Publication Date(Web):
DOI:10.1002/cssc.201300360
Co-reporter:Jinshui Zhang, Mingwen Zhang, Guigang Zhang, and Xinchen Wang
ACS Catalysis 2012 Volume 2(Issue 6) pp:940
Publication Date(Web):April 18, 2012
DOI:10.1021/cs300167b
Sulfur-mediated synthesis has been demonstrated as a simple but efficient pathway to control the texture and electronic structure of poly(tris-triazine) based graphitic carbon nitride semiconductors with improved photocatalytic reactivity over the pristine counterpart. Here, we advance this strategy by employing cheap and easily available elemental sulfur as the external sulfur species instead of sulfur-containing precursors for the sulfur-mediated synthesis of polymeric carbon nitride photocatalysts. Characterization results revealed that the multiple thermal condensations of carbon nitride precursors in the hot sulfur flux provided a facile means to promote the formation of graphitic-like carbon nitride conjugated systems, altering the traditional route of thermal-induced self-polymerization of melamine. The textural, electronic, and optical properties of the resultants organic semiconductors was therefore strongly modified to endow the materials with improved physical and chemical properties, as demonstrated by the enhanced photocatalytic activity for water reduction and oxidation under visible light irradiation with wavelength >420 nm. This result again underlines the benefit of a sulfur-mediated approach to construct and manipulate polymeric carbon nitride networks for sustainable applications in catalysis and photocatalysis.Keywords: carbon nitride; elemental sulfur; photocatalysis; solar energy conversion; sulfur-mediated synthesis;
Co-reporter:Jinshui Zhang, Marek Grzelczak, Yidong Hou, Kazuhiko Maeda, Kazunari Domen, Xianzhi Fu, Markus Antonietti and Xinchen Wang
Chemical Science 2012 vol. 3(Issue 2) pp:443-446
Publication Date(Web):13 Oct 2011
DOI:10.1039/C1SC00644D
The search for earth-abundant semiconductors and co-catalysts for water oxidation is an important step towards conversion of solar energy into fuel chemicals in a sustainable manner. Here, we report the integration of Co3O4 nanoparticles within graphitic carbon nitride to construct a nanohybrid photocatalyst made of abundant elements for the photocatalytic generation of oxygen from water, achieving an apparent quantum efficiency of 1.1% at 420 nm for water splitting to oxygen. The present system shows great promise in polymer photocatalysis for applications in future energy cycles based on sustainable materials.
Co-reporter:Guigang Zhang, Jinshui Zhang, Mingwen Zhang and Xinchen Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 16) pp:8083-8091
Publication Date(Web):16 Mar 2012
DOI:10.1039/C2JM00097K
Converting solar energy into hydrogen gas by water splitting is considered as a long-term solution to address global energy and environmental problems. Great effort has been devoted to the search for abundant systems for the purpose of efficient capture, conversion, and storage of solar energy in a cost-effective manner. To further advance the recently-developed carbon nitride photocatalysis for solar hydrogen generation, thiourea, a sulfur-containing compound, was used as a cheap and easily-available starting material for the synthesis of graphitic carbon nitride semiconductors. The as-prepared photocatalysts were subjected to several characterizations, and the results showed that the heating temperature and the presence of sulfur motifs offer a facile chemical pathway for the control of the condensation/polymerization of carbon nitride, and thus adjusting their textural and electronic properties. Photocatalytic activity experiments demonstrated that the g-C3N4 synthesized from thiourea exhibited a much higher H2 production rate than that of g-C3N4 prepared from dicyanamide or urea, and this activity can be further enhanced by increasing the condensation temperature.
Co-reporter:Fangzheng Su, Markus Antonietti and Xinchen Wang
Catalysis Science & Technology 2012 vol. 2(Issue 5) pp:1005-1009
Publication Date(Web):15 Feb 2012
DOI:10.1039/C2CY00012A
Deprotonated mesoporous graphitic carbon nitride (mpg-C3N4) was achieved by a simple method of treatment of as-prepared materials with different basic aqueous solutions (K2CO3, KOH, tBuOK). The resultant polymeric materials show significantly enhanced basicity, while maintaining the original mesoporous structure. It was then used as a heterogeneous base catalyst for Knoevenagel condensations and transesterification reactions. Catalytic results show that the deprotonated mpg-C3N4 exhibits high efficiency for promoting these reactions as a solid and polymeric catalyst. The reactions between various aldehydes and malonic derivatives, alcohols and β-ketoesters could proceed smoothly in the presence of deprotonated mpg-C3N4. The catalyst could be recycled and reused for several runs without any loss of intrinsic catalytic activity.
Co-reporter:Yanjuan Cui, Jianhui Huang, Xianzhi Fu and Xinchen Wang
Catalysis Science & Technology 2012 vol. 2(Issue 7) pp:1396-1402
Publication Date(Web):29 Mar 2012
DOI:10.1039/C2CY20036H
Mesoporous graphitic carbon nitrides were synthesized by a thermal-induced polymerization of NH4SCN on the surface of silica nanoparticles as the templates. The catalysts thus obtained were used as visible light photocatalysts for the degradation of organic pollutants in water. The physicochemical properties of catalysts were characterized by several techniques. The photocatalytic activity of samples was evaluated by the decomposition of chlorophenol and phenol in aqueous phase. Results demonstrated that mesoporous graphitic carbon nitrides can photocatalytically oxidize and eventually mineralize organic pollutants in aqueous solution under visible light irradiation. The photocatalysts can induce the formation of reactive oxy-species such as H2O2, ˙OH and ˙O2−/˙OOH under visible light irradiation, while keeping a high photocatalytic reactivity during recycling operations. The higher activity of mesoporous carbon nitrides compared to nonporous carbon nitride can be attributed to their enlarged surface area and enhanced light-harvesting effect, facilitating the photogeneration of active oxy-radicals in water.
Co-reporter:Yanjuan Cui, Zhengxin Ding, Ping Liu, Markus Antonietti, Xianzhi Fu and Xinchen Wang
Physical Chemistry Chemical Physics 2012 vol. 14(Issue 4) pp:1455-1462
Publication Date(Web):09 Dec 2011
DOI:10.1039/C1CP22820J
Semiconducting carbon nitride materials were successfully prepared via a thermal poly-condensation of dicyandiamide as a precursor at >500 °C. The resulting materials were investigated as metal-free catalysts for the activation of H2O2 with visible light under mild conditions, using the decomposition of Rhodamine B (RhB) in aqueous solution as a model reaction. Results revealed that carbon nitride catalysts can activate H2O2 to generate reactive oxy-radicals under visible light irradiation without employment of any metal additives, leading to the mineralization of the dye. Factors affecting the degradation of organic compounds are pH values and the concentration of H2O2. Recycling of the catalyst indicated no obvious deactivation during the entire catalytic reaction, indicating good (photo)chemical stability of metal-free polymeric carbon nitride photocatalysts for environmental purification. This study demonstrated a promising approach for the activation of green oxidant, hydrogen peroxide, by the newly-developed polymer photocatalysts for environmental remediation and oxidation catalysis.
Co-reporter:Baihua Long, Jianhui Huang, Xinchen Wang
Progress in Natural Science: Materials International 2012 Volume 22(Issue 6) pp:644-653
Publication Date(Web):December 2012
DOI:10.1016/j.pnsc.2012.11.007
A rod-shaped BiPO4 photocatalyst was prepared by a simple hydrothermal method for light-induced catalytic degradation of stable aromatic compounds such as benzene in gas phase under ambient conditions. The samples were subjected to various technical characterizations including X-ray diffraction (XRD), transmission electron microscopy (TEM), UV/vis and FTIR spectrum, to determine the crystal structure, morphology, and optical properties of the as-prepared photocatalysts. Results indicate that BiPO4 exhibits much higher photocatalytic activity and stability under UV light irradiation than that of commercial TiO2 (Degussa P25) in the degradation of benzene to CO2. The active radical species involved in the degradation reactions over BiPO4 photocatalyst have been investigated by the spin-trapping electron paramagnetic resonance (EPR) spectra and a photoluminescence technique. Theoretical calculations reveal that BiPO4 contains highly-dispersive conduction bands, enabling high mobility of the photo-generated carries and therefore leading to fast charge transfer and separation.
Co-reporter:Jinshui Zhang;Guigang Zhang;Xiufang Chen;Dr. Sen Lin;Lennart Möhlmann;Dr. Grzegorz Do&x142;&x119;ga;Dr. Grzegorz Lipner; Markus Antonietti; Siegfried Blechert; Xinchen Wang
Angewandte Chemie 2012 Volume 124( Issue 13) pp:3237-3241
Publication Date(Web):
DOI:10.1002/ange.201106656
Co-reporter:Jinshui Zhang;Mingwen Zhang;Dr. Rui-Qing Sun ; Xinchen Wang
Angewandte Chemie 2012 Volume 124( Issue 40) pp:10292-10296
Publication Date(Web):
DOI:10.1002/ange.201205333
Co-reporter:Yanjuan Cui; Zhengxin Ding; Xianzhi Fu ; Xinchen Wang
Angewandte Chemie International Edition 2012 Volume 51( Issue 47) pp:11814-11818
Publication Date(Web):
DOI:10.1002/anie.201206534
Co-reporter:Jinshui Zhang;Guigang Zhang;Xiufang Chen;Dr. Sen Lin;Lennart Möhlmann;Dr. Grzegorz Do&x142;&x119;ga;Dr. Grzegorz Lipner; Markus Antonietti; Siegfried Blechert; Xinchen Wang
Angewandte Chemie International Edition 2012 Volume 51( Issue 13) pp:3183-3187
Publication Date(Web):
DOI:10.1002/anie.201106656
Co-reporter:Jinshui Zhang;Mingwen Zhang;Dr. Rui-Qing Sun ; Xinchen Wang
Angewandte Chemie International Edition 2012 Volume 51( Issue 40) pp:10145-10149
Publication Date(Web):
DOI:10.1002/anie.201205333
Co-reporter:Yanjuan Cui; Zhengxin Ding; Xianzhi Fu ; Xinchen Wang
Angewandte Chemie 2012 Volume 124( Issue 47) pp:11984-11988
Publication Date(Web):
DOI:10.1002/ange.201206534
Co-reporter:Jinshui Zhang, Jianhua Sun, Kazuhiko Maeda, Kazunari Domen, Ping Liu, Markus Antonietti, Xianzhi Fu and Xinchen Wang
Energy & Environmental Science 2011 vol. 4(Issue 3) pp:675-678
Publication Date(Web):06 Dec 2010
DOI:10.1039/C0EE00418A
Sulfur-mediated synthesis has been developed to modify the texture, optical and electronic properties, as well as the photocatalytic functions of a carbon nitride semiconductor. The water oxidation reaction has been achieved at a moderate rate with only photocatalysts without the aid of co-factors.
Co-reporter:Yanjuan Cui, Jinshui Zhang, Guigang Zhang, Jianhui Huang, Ping Liu, Markus Antonietti and Xinchen Wang
Journal of Materials Chemistry A 2011 vol. 21(Issue 34) pp:13032-13039
Publication Date(Web):29 Jul 2011
DOI:10.1039/C1JM11961C
Graphitic carbon nitride was synthesized by direct thermal polymerization of ammonium thiocyanate as the precursor. The transfer of this simple thermal-induced polymerization onto hard-templates with various nanoarchitectures enables the fabrication of nanostructured carbon nitridesvia a soft-chemical synthesis, while the involvement of a sulfur species within the reaction cascade offers additional chemical control of the texture and the electronic structures. The catalysts were subjected to several characterizations, and the results obtained revealed that nanoporous carbon nitrides can be obtained by templating with nanosized silica and SBA-15. Photocatalytic activity was evaluated toward hydrogen evolution from proton solution with visible light. Results show that g-C3N4 synthesized from ammonium thiocyanate exhibited improved photoactivity in comparison with g-C3N4 obtained from dicyandiamide. Further improvement in the activity was achieved by creating the nanostructures in g-C3N4. This is due to the enhanced surface area obtained which is favorable for light-harvesting and mass-transfer, as well as to the increased redox potential.
Co-reporter:Dr. Zhengxin Ding;Xiufang Chen; Markus Antonietti; Xinchen Wang
ChemSusChem 2011 Volume 4( Issue 2) pp:274-281
Publication Date(Web):
DOI:10.1002/cssc.201000149
Abstract
Modification of graphitic carbon nitride (g-C3N4) photocatalyst with transition metals was achieved with a simple soft-chemical approach using dicyandiamide monomer and metal chloride as precursors, in combination with a thermal-induced polycondensation at 600 °C under nitrogen atmosphere. The resultant organic–inorganic hybrid materials were thoroughly characterized by a variety of techniques, including X-ray diffraction (XRD), UV/Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), N2-sorption, transmission electron microscopy (TEM), photoluminescence (PL), and FTIR. Benzene hydroxylation and styrene epoxidation reactions were employed to evaluate the catalytic/photocatalytic activity of the synthesized g-C3N4-based catalysts. Results showed that Fe- and Cu-modified g-C3N4 were active for the hydroxylation of benzene to phenol using H2O2 under mild conditions. It was also found that g-C3N4 could promote the catalytic epoxidation of styrene using molecular oxygen as the primary oxidant; after modification with Co and Fe, the catalytic performance for styrene epoxidation with O2 could be significantly improved, especially when coupled with visible-light irradiation.
Co-reporter:Li Zhao;Xiufang Chen;Yuanjian Zhang;Wei Wei;Yuhan Sun;Markus Antonietti;Maria-Magdalena Titirici
Advanced Materials 2010 Volume 22( Issue 30) pp:3317-3321
Publication Date(Web):
DOI:10.1002/adma.201000660
Co-reporter:Fangzheng Su ; Smitha C. Mathew ; Grzegorz Lipner ; Xianzhi Fu ; Markus Antonietti ; Siegfried Blechert
Journal of the American Chemical Society 2010 Volume 132(Issue 46) pp:16299-16301
Publication Date(Web):November 2, 2010
DOI:10.1021/ja102866p
Mesoporous carbon nitride (mpg-C3N4) polymer can function as a metal-free photocatalyst to activate O2 for the selective oxidation of benzyl alcohols with visible light, avoiding the cost, toxicity, and purification problems associated with corresponding transition-metal systems. By combining the surface basicity and semiconductor functions of mpg-C3N4, the photocatalytic system can realize a high catalytic selectivity to generate benzaldehyde. The metal-free photocatalytic system also selectively converts other alcohol substrates to their corresponding aldehydes/ketones, demonstrating a potential pathway of accessing traditional mild radical chemistry with nitroxyl radicals.
Co-reporter:Jianhui Huang, Yanjuan Cui and Xinchen Wang
Environmental Science & Technology 2010 Volume 44(Issue 9) pp:3500-3504
Publication Date(Web):April 13, 2010
DOI:10.1021/es1001264
A ZnGe oxynitride semiconductor was prepared by a solid-state reaction using GeO2 and ZnO under NH3 flow. The catalyst was used as a visible-light photocatalyst for the decomposition of organic compounds in polluted water. The physicochemical properties of the synthesized ZnGe oxynitride photocatalysts were characterized by several techniques, and aqueous photocatalytic activity was evaluated via the decomposition of model organic compounds including Rhodamine B, Methyl orange, Methylene blue, 4-chlorophenol, and salicylic acid. The results demonstrate that ZnGe oxynitride can photocatalytically oxidize organic pollutants in aqueous solution under visible light irradiation, suffering no obvious catalyst deactivation during reaction testing. The possible active species in the photocatalytic process are also discussed.
Co-reporter:Zhengxin Ding, Jianhui Huang and Xinchen Wang
Physical Chemistry Chemical Physics 2010 vol. 12(Issue 23) pp:5983-5985
Publication Date(Web):15 Apr 2010
DOI:10.1039/C000298B
Iron-doped titanium dioxide nanoarchitectures with ordered mesopore periodicity and enhanced photocatalytic activity have been developed as photofunctional materials for environmental purification.
Co-reporter:Jinshui Zhang;Xiufang Chen ;Kazuhiro Takanabe ;Kazuhiko Maeda ;Kazunari Domen ;JanDirk Epping Dr.;Xianzhi Fu ;Markus Antonietti
Angewandte Chemie International Edition 2010 Volume 49( Issue 2) pp:441-444
Publication Date(Web):
DOI:10.1002/anie.200903886
Co-reporter:
Nature Materials 2009 8(1) pp:
Publication Date(Web):2008-11-09
DOI:10.1038/nmat2317
The production of hydrogen from water using a catalyst and solar energy is an ideal future energy source, independent of fossil reserves. For an economical use of water and solar energy, catalysts that are sufficiently efficient, stable, inexpensive and capable of harvesting light are required. Here, we show that an abundant material, polymeric carbon nitride, can produce hydrogen from water under visible-light irradiation in the presence of a sacrificial donor. Contrary to other conducting polymer semiconductors, carbon nitride is chemically and thermally stable and does not rely on complicated device manufacturing. The results represent an important first step towards photosynthesis in general where artificial conjugated polymer semiconductors can be used as energy transducers.
Co-reporter:Xiufang Chen, Xinchen Wang and Xianzhi Fu
Energy & Environmental Science 2009 vol. 2(Issue 8) pp:872-877
Publication Date(Web):05 May 2009
DOI:10.1039/B904012A
Photocatalytic purification methods for polluted air and wastewater show great promise for environmental remediation, allowing the “green” mineralization of organic pollutants under ambient conditions. The creation of macro/mesopores in semiconductor photocatalysts has been found to improve the overall photocatalytic efficiency, but porous systems are generally unstable against thermal sintering, which is indispensable for removing organic templates and enhancing structural crystallization. In this study, we employed nanosized ZrO2 and SiO2 as structural modifiers to improve the structural stability in a macro/mesoporous TiO2 photocatalyst. This was accomplished by soft-chemical synthesis in the presence of surfactants, followed by calcination at high temperatures. The resulting porous TiO2-based nanocomposites not only feature enhanced textural properties and improved thermal stability, but also show an improvement in photocatalytic activity over pure TiO2. The introduction of a secondary phase imparts the additional functions of improved surface acidity and extra binding sites onto the porous structures. The favorable textural properties, along with the improved surface functions contribute to the high photocatalytic activity of catalysts calcined at high temperatures.
Co-reporter:Xinchen Wang;Xiufang Chen;Arne Thomas;Xianzhi Fu;Markus Antonietti
Advanced Materials 2009 Volume 21( Issue 16) pp:1609-1612
Publication Date(Web):
DOI:10.1002/adma.200802627
Co-reporter:Xiufang Chen ; Jinshui Zhang ; Xianzhi Fu ; Markus Antonietti
Journal of the American Chemical Society 2009 Volume 131(Issue 33) pp:11658-11659
Publication Date(Web):July 31, 2009
DOI:10.1021/ja903923s
A bioinspired iron-based catalyst with semiconductor photocatalytic functions in combination with a high surface area holds promise for synthetic chemistry via combining photocatalysis with organosynthesis. Here exemplified for phenol synthesis, Fe-g-C3N4/SBA-15 is able to oxidize benzene to phenol with H2O2 even without the aid of strong acids or alkaline promoters. By taking advantage of both catalysis and photocatalyisis functions of g-C3N4 nanoparticles, the yield of the phenol can be markedly promoted.
Co-reporter:Xinchen Wang ; Kazuhiko Maeda ; Xiufang Chen ; Kazuhiro Takanabe ; Kazunari Domen ; Yidong Hou ; Xianzhi Fu ;Markus Antonietti
Journal of the American Chemical Society 2009 Volume 131(Issue 5) pp:1680-1681
Publication Date(Web):January 21, 2009
DOI:10.1021/ja809307s
We investigated semiconductor characteristics for polymeric carbon nitride as a metal-free photocatalyst working with visible light and have shown that the efficiency of hydrogen production by photochemical water reduction can be improved by ∼1 order of magnitude by introducing the right type of mesoporosity into polymeric C3N4. We anticipate a wide rang of potential application of C3N4 as energy transducers for artificial photosynthesis in general, especially with a 3D continuous nanoarchitecture. Moreover, the results of finding photoactivity for carbon nitride nanoparticles can enrich the discussion on prebiotic chemistry of the Earth, as HCN polymer clusters are unequivocal in the solar system.
Co-reporter:Xiufang Chen, Young-Si Jun, Kazuhiro Takanabe, Kazuhiko Maeda, Kazunari Domen, Xianzhi Fu, Markus Antonietti and Xinchen Wang
Chemistry of Materials 2009 Volume 21(Issue 18) pp:4093
Publication Date(Web):August 19, 2009
DOI:10.1021/cm902130z
Co-reporter:Xinnian Zhang, Jianhui Huang, Kaining Ding, Yidong Hou, Xinchen Wang and Xianzhi Fu
Environmental Science & Technology 2009 Volume 43(Issue 15) pp:5947-5951
Publication Date(Web):June 24, 2009
DOI:10.1021/es900403a
Porous nanocrystalline ZnGa2O4 catalysts were synthesized by a simple soft-chemical method at low temperature. The catalysts were characterized by XRD, nitrogen adsorption, SEM, TEM, UV/vis, and FT-IR spectroscopy. The activity of the photocatalysts was evaluated by decomposition of benzene and its derivatives in the gas phase. It was found that hydrothermal treatment resulted in the formation of spinel ZnGa2O4 with a large surface area of 43−201 m2·g−1 depending on the synthetic temperature. The optimum synthetic temperature was found to be 80 °C, at which the sample possessed a surface area of 201 m2·g−1 and had the highest photocatalytic activity for degrading benzene. A comparison with TiO2 and Pt/TiO2 showed that the ZnGa2O4 (synthesized at 80 °C) had improved photocatalytic activity and durability over the TiO2-based catalysts. No remarkable deactivation of the ZnGa2O4 catalyst was observed in 80 h photoreaction, whereas the TiO2 deactivated remarkably in 24 h reaction. The high photocatalytic performance of porous ZnGa2O4 catalysts can be explained by the large specific surface area, the accessible porous framework, and the high redox power.
Co-reporter:Jianhui Huang, Kaining Ding, Xinchen Wang and Xianzhi Fu
Langmuir 2009 Volume 25(Issue 14) pp:8313-8319
Publication Date(Web):May 5, 2009
DOI:10.1021/la9005345
A nanostructured Cd2Ge2O6 photocatalyst was successfully prepared by a hydrothermal process. The photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV/vis, N2 adsorption−desorption, and Fourier transform infrared (FTIR) techniques. The photocatalytic property of the material was evaluated via the decomposition of benzene in the gas phase with light illumination and was compared with that of commercial titania (Degussa P25) and Pt/TiO2. The electronic band structure of Cd2Ge2O6 was analyzed by density functional theory (DFT) calculation. Results reveal that the prepared Cd2Ge2O6 has unique geometric and electronic properties, which in combination with its superior textural properties makes it a new semiconductor photocatalyst for environmental purification of benzene in air with molecular oxygen under ambient conditions. It was also found that the Cd2Ge2O6 was more active and stable than TiO2-based catalysts in the photocatalytic decomposition of other volatile aromatic pollutants including toluene and ethylbenzene. The enhanced photocatalytic performance of Cd2Ge2O6 can be explained by the special band structure, and geometric and electronic feature, in unison with the high surface area nanoporous framework.
Co-reporter:Jianhui Huang, Xinchen Wang, Yidong Hou, Xiufang Chen, Ling Wu and Xianzhi Fu
Environmental Science & Technology 2008 Volume 42(Issue 19) pp:7387-7391
Publication Date(Web):August 26, 2008
DOI:10.1021/es800744e
A rod-shaped Zn2GeO4 photocatalyst has been successfully prepared by a surfactant-assisted hydrothermal method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, UV/vis, N2 adsorption−desorption, and FTIR techniques. The photocatalytic activity of the sample was evaluated by the decomposition of benzene in the gas phase under UV light illumination and was compared with that of bulk Zn2GeO4, commercial titania (Degussa P25), and Pt/P25. The results revealed that the Zn2GeO4 nanorods had the best photocatalytic activity for mineralizing benzene to CO2 among the catalysts examined. No obvious deactivation of Zn2GeO4 nanorods was observed during the prolonged operation of 140 h. It was found that the Zn2GeO4 was also more active and stable than TiO2-based catalysts toward photocatalytic decomposition of other volatile aromatic pollutants (e.g., toluene and ethylbenzene).
Co-reporter:Jianhui Huang;Kaining Ding Dr.;Yidong Hou Dr. Dr.;Xianzhi Fu Dr.
ChemSusChem 2008 Volume 1( Issue 12) pp:1011-1019
Publication Date(Web):
DOI:10.1002/cssc.200800166
Abstract
Zn2GeO4 nanorods were prepared by a surfactant-assisted hydrothermal method and used as photocatalysts for the decomposition of organic pollutants in water. The physicochemical properties of the Zn2GeO4 photocatalysts were characterized by several techniques, and their photocatalytic activity was evaluated by the decomposition of methyl orange, salicylic acid, and 4-chlorophenol in aqueous solution. The results revealed that the Zn2GeO4 nanorods have a much higher photocatalytic activity for decomposing organic pollutants in aqueous solution than both Zn2GeO4 prepared by a conventional solid-state reaction and widely used TiO2 (Degussa P25). There is no obvious deactivation of Zn2GeO4 nanorods in the photocatalytic reactions. The intermediates of the photocatalytic reactions were monitored by LC-MS, and possible photocatalytic reaction pathways as to how Zn2GeO4 nanorods degrade organic dyes were proposed.
Co-reporter:Guigang Zhang, Xinchen Wang
Journal of Catalysis (November 2013) Volume 307() pp:246-253
Publication Date(Web):1 November 2013
DOI:10.1016/j.jcat.2013.07.026
•Phenylurea is found to be a beneficial co-monomer of urea to synthesize reactive carbon nitride photocatalysts.•Co-polymerization with phenylurea can effectively extend the π-conjugated system of carbon nitride.•Both electronic and surface structures are modified by co-polymerization.•The fusion of phenyl group in conjugated carbon nitride greatly enhances the photocatalytic performance.Phenylurea has been integrated into the traditional polymerization route of carbon nitride (CN) precursors (e.g., urea, thiourea, dicyandiamide, and ammonium thiocyanide) in a facile one-pot approach, to modify the chemical composition, electronic structure, and catalytic performance of graphitic CN (g-CN). Results revealed that the co-polymerization of phenylurea with urea dramatically modifies the optical and electronic properties of g-CN, leading to a remarkable improvement by a factor of 9 in the photocatalytic activity of g-CN (when coupled with Pt as a co-catalyst) in an assay of hydrogen evolution reaction, while still keeping a high catalytic stability during pre-longed operations. The active catalyst is eventually a hybrid organocatalyst that is a heterogeneous Pt catalyst supported on a urea-based polymer. The promotional effect of phenylurea as the co-monomer for urea on the activity and stability of Pt/g-CN could be related to the extension of delocalized π-conjugated system of CN heterocycles, as a result of the fusion of phenyl motifs in the CN framework. The thus created surface dyadic structure favors the separation and migration of charge-carriers photoexcited upon light illumination. This work highlights a wide accessibility of chemical protocols for the design and synthesis of functional CN photocatalysts at molecular levels by applying suitable CN precursors and co-monomers.Graphical abstractCo-polymerization with phenylurea can effectively extend the conjugated system of graphitic carbon nitride to optimize its physicochemical properties for solar hydrogen evolution.Download high-res image (44KB)Download full-size image
Co-reporter:Jinshui Zhang, Mingwen Zhang, Sen Lin, Xianzhi Fu, Xinchen Wang
Journal of Catalysis (February 2014) Volume 310() pp:24-30
Publication Date(Web):1 February 2014
DOI:10.1016/j.jcat.2013.01.008
Molecular doping of conjugated carbon nitride (CN) with thiophene donors was applied for the modification of CN photocatalysts. The incorporation of electron-rich thiophene entities in the conjugated polymer matrix can effectively change the intrinsic bulk and surface features of CN, such as engineering the electronic structure with tunable bandgap and promoting the charge-carrier migration and separation via forming surface dyadic structures. A significant alteration in the texture, morphology, and crystalline was also observed for the thiophene-modified CN samples. The combined benefits of the molecular doping in terms of bulk, surface, and texture properties lead to an improvement in the photocatalytic activity for H2 generation with visible light, which underlines the importance of organic chemistry protocols for the chemical modification of newly developed metal-free, polymeric photocatalysts.Graphical abstractMolecular doping of carbon nitride with thiophene donors can effectively extend the π conjugated system to optimize its physiochemical properties for photocatalytic hydrogen evolution.Download high-res image (47KB)Download full-size imageHighlights► Doping with thiophene can effectively extends the π conjugated system of carbon nitride. ► Doping effect is predicted by DFT calculations. ► Control to narrowing the bandgap is achieved via varying the use of thiophene content. ► Both of the electronic features and surface structure are altered by doping. ► Integrating thiophene in carbon nitride greatly enhances the photocatalytic performance.
Co-reporter:Huiquan Li, Yuxing Liu, Yumin Cui, Wenbao Zhang, Cong Fu, Xinchen Wang
Applied Catalysis B: Environmental (April 2016) Volume 183() pp:426-432
Publication Date(Web):April 2016
DOI:10.1016/j.apcatb.2015.11.012
Co-reporter:Xiufang Chen, Xinchen Wang, Yidong Hou, Jianhui Huang, Ling Wu, Xianzhi Fu
Journal of Catalysis (1 April 2008) Volume 255(Issue 1) pp:59-67
Publication Date(Web):1 April 2008
DOI:10.1016/j.jcat.2008.01.025
Postnitridation annealing has a remarkable effect on the surface property and photocatalytic performance of N-doped TiO2 for photocatalytic oxidation of ethylene. The activity of N-doped TiO2 under visible light illumination (λ>420 nm) can be enhanced fourfold by annealing the sample at 400 °C. Characterization results show that the thermal annealing reduces surface oxygen vacancies, removes surface-adsorbed NH3, and facilitates the adsorption of molecular oxygen on catalyst surface. Such a surface reconstruction contributes to the enhanced photocatalytic activity of the N-doped TiO2. The postcalcination also improves the photocatalytic stability of the N-doped TiO2 by stabilizing nitrogen atoms in the TiO2 lattice. A N-doped TiO2 sample without postcalcination suffers from a gradual deactivation, due mainly to the passivation of the catalyst surface by oxidized nitrogen species (e.g., hyponitrite, nitrite ions, and nitrate ions) formed during the photocatalytic degradation of ethylene.
Co-reporter:Baihua Long, Jinliang Lin and Xinchen Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 9) pp:NaN2951-2951
Publication Date(Web):2013/11/22
DOI:10.1039/C3TA14339B
A cheap and easily-available organosulfur compound, guanidine thiocyanate, has been used to synthesize graphitic carbon nitride (g-C3N4) by a thermally-induced desulfurization and polymerization of the precursor. Photocatalytic activity experiments demonstrated that the g-C3N4 synthesized from guanidine thiocyanate exhibited a much higher H2 evolution rate than the reference sample prepared from dicyanamide. Further improvement in the activity was achieved by optimization of the condensation temperature. Based on X-ray photoelectron spectroscopy analysis, the samples synthesized at a high temperature of 700 °C feature a high crystallinity and a low density of surface defects, with an enhanced optical absorbance extending to the visible light region. As a result, the sample prepared at 700 °C has been found to be 7 times more reactive towards photocatalytic hydrogen evolution than the sample polymerized at the normal temperature of 550 °C. Other guanidine halides have also been applied to synthesize g-C3N4 materials, and the structure and activity of the resultant g-C3N4 were compared to the carbon nitride polymer from guanidine thiocyanate.
Co-reporter:Sibo Wang, Jinliang Lin and Xinchen Wang
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 28) pp:NaN14660-14660
Publication Date(Web):2014/06/02
DOI:10.1039/C4CP02173H
A noble-metal-free system for photochemical reduction of CO2 has been developed by integrating graphitic carbon nitride (g-C3N4) with a cobalt-containing zeolitic imidazolate framework (Co-ZIF-9). g-C3N4 acts as a semiconductor photocatalyst, whereas Co-ZIF-9 is a cocatalyst that facilitates the capture/concentration of CO2 and promotes light-induced charge separation. The two materials cooperate efficiently to catalyze CO2-to-CO conversion upon visible light illumination under mild reaction conditions. A 13C-labelled isotropic experiment proved that CO2 is the carbon source of the produced CO. Even without noble metals, the system still achieved an apparent quantum yield of 0.9 percent. The system displayed high photocatalytic stability, without noticeable alterations in the chemical and crystal structures of g-C3N4 and Co-ZIF-9 after the reaction.
Co-reporter:Guigang Zhang, Jinshui Zhang, Mingwen Zhang and Xinchen Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 16) pp:NaN8091-8091
Publication Date(Web):2012/03/16
DOI:10.1039/C2JM00097K
Converting solar energy into hydrogen gas by water splitting is considered as a long-term solution to address global energy and environmental problems. Great effort has been devoted to the search for abundant systems for the purpose of efficient capture, conversion, and storage of solar energy in a cost-effective manner. To further advance the recently-developed carbon nitride photocatalysis for solar hydrogen generation, thiourea, a sulfur-containing compound, was used as a cheap and easily-available starting material for the synthesis of graphitic carbon nitride semiconductors. The as-prepared photocatalysts were subjected to several characterizations, and the results showed that the heating temperature and the presence of sulfur motifs offer a facile chemical pathway for the control of the condensation/polymerization of carbon nitride, and thus adjusting their textural and electronic properties. Photocatalytic activity experiments demonstrated that the g-C3N4 synthesized from thiourea exhibited a much higher H2 production rate than that of g-C3N4 prepared from dicyanamide or urea, and this activity can be further enhanced by increasing the condensation temperature.
Co-reporter:Yanjuan Cui, Zhengxin Ding, Ping Liu, Markus Antonietti, Xianzhi Fu and Xinchen Wang
Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 4) pp:NaN1462-1462
Publication Date(Web):2011/12/09
DOI:10.1039/C1CP22820J
Semiconducting carbon nitride materials were successfully prepared via a thermal poly-condensation of dicyandiamide as a precursor at >500 °C. The resulting materials were investigated as metal-free catalysts for the activation of H2O2 with visible light under mild conditions, using the decomposition of Rhodamine B (RhB) in aqueous solution as a model reaction. Results revealed that carbon nitride catalysts can activate H2O2 to generate reactive oxy-radicals under visible light irradiation without employment of any metal additives, leading to the mineralization of the dye. Factors affecting the degradation of organic compounds are pH values and the concentration of H2O2. Recycling of the catalyst indicated no obvious deactivation during the entire catalytic reaction, indicating good (photo)chemical stability of metal-free polymeric carbon nitride photocatalysts for environmental purification. This study demonstrated a promising approach for the activation of green oxidant, hydrogen peroxide, by the newly-developed polymer photocatalysts for environmental remediation and oxidation catalysis.
Co-reporter:Yanjuan Cui, Jinshui Zhang, Guigang Zhang, Jianhui Huang, Ping Liu, Markus Antonietti and Xinchen Wang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 34) pp:NaN13039-13039
Publication Date(Web):2011/07/29
DOI:10.1039/C1JM11961C
Graphitic carbon nitride was synthesized by direct thermal polymerization of ammonium thiocyanate as the precursor. The transfer of this simple thermal-induced polymerization onto hard-templates with various nanoarchitectures enables the fabrication of nanostructured carbon nitridesvia a soft-chemical synthesis, while the involvement of a sulfur species within the reaction cascade offers additional chemical control of the texture and the electronic structures. The catalysts were subjected to several characterizations, and the results obtained revealed that nanoporous carbon nitrides can be obtained by templating with nanosized silica and SBA-15. Photocatalytic activity was evaluated toward hydrogen evolution from proton solution with visible light. Results show that g-C3N4 synthesized from ammonium thiocyanate exhibited improved photoactivity in comparison with g-C3N4 obtained from dicyandiamide. Further improvement in the activity was achieved by creating the nanostructures in g-C3N4. This is due to the enhanced surface area obtained which is favorable for light-harvesting and mass-transfer, as well as to the increased redox potential.
Co-reporter:Guigang Zhang, Shaohong Zang, Zhi-An Lan, Caijin Huang, Guosheng Li and Xinchen Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 35) pp:NaN17950-17950
Publication Date(Web):2015/08/04
DOI:10.1039/C5TA04767F
Cobalt selenide has been developed as an effective cocatalyst to decorate visible light photocatalysts, including WO3, BiVO4 and g-C3N4, establishing intense surface contact with substrates for the photocatalytic water oxidation reaction. Compared with CoOx and CoSx, CoSe2 is superior for improving the photocatalytic water oxidation activity due to the lower anionic electronegativity, which leads to dense adhesion and enables fast interfacial charge transfer for the water oxidation reaction.
Co-reporter:Sibo Wang, Zhengxin Ding and Xinchen Wang
Chemical Communications 2015 - vol. 51(Issue 8) pp:NaN1519-1519
Publication Date(Web):2014/11/25
DOI:10.1039/C4CC07225A
Spinel ZnCo2O4 nanostructures have shown great opportunities in energy related areas. However, the applications of ZnCo2O4 for the conversion of CO2 are much less reported. Herein, we present the use of mesoporous ZnCo2O4 nanorods as efficient and high stable cocatalysts for the photochemical reduction of CO2 under mild reaction conditions.
Co-reporter:Zhengxin Ding, Jianhui Huang and Xinchen Wang
Physical Chemistry Chemical Physics 2010 - vol. 12(Issue 23) pp:NaN5985-5985
Publication Date(Web):2010/04/15
DOI:10.1039/C000298B
Iron-doped titanium dioxide nanoarchitectures with ordered mesopore periodicity and enhanced photocatalytic activity have been developed as photofunctional materials for environmental purification.
Co-reporter:Yan Chen, Jinshui Zhang, Mingwen Zhang and Xinchen Wang
Chemical Science (2010-Present) 2013 - vol. 4(Issue 8) pp:NaN3248-3248
Publication Date(Web):2013/05/28
DOI:10.1039/C3SC51203G
A thiophene motif has been integrated into mesoporous carbon nitride (MCN) to improve the photoactivation of molecular oxygen towards the selective oxidation of alcohols. This modification also extends the photoactive part of the spectrum of MCN by electronic modification of the conjugated system.
Co-reporter:Jianhui Huang, Wingkei Ho and Xinchen Wang
Chemical Communications 2014 - vol. 50(Issue 33) pp:NaN4340-4340
Publication Date(Web):2014/03/04
DOI:10.1039/C3CC48374F
Covalent carbon nitride polymers were applied as metal-free robust catalysts for the inactivation of Escherichia coli K-12 (E. coli), a common Gram-negative bacterium, under visible light illumination. The results demonstrated that the creation of antibacterial function on the surface of conjugated polymers has now become possible.
Co-reporter:Guigang Zhang, Zhi-An Lan and Xinchen Wang
Chemical Science (2010-Present) 2017 - vol. 8(Issue 8) pp:NaN5274-5274
Publication Date(Web):2017/06/06
DOI:10.1039/C7SC01747B
Graphitic carbon nitride based polymers, being metal-free, accessible, environmentally benign and sustainable, have been widely investigated for artificial photosynthesis in recent years for the photocatalytic splitting of water to produce hydrogen fuel. However, the photocatalytic stoichiometric splitting of pure water into H2 and O2 with a molecular ratio of 2:1 is far from easy, and is usually hindered by the huge activation energy barrier and sluggish surface redox reaction kinetics. Herein, we provide a concise overview of cocatalyst modified graphitic carbon nitride based photocatalysts, with our main focus on the modulation of the water splitting redox reaction kinetics. We believe that a timely and concise review on this promising but challenging research topic will certainly be beneficial for general readers and researchers in order to better understand the property–activity relationship towards overall water splitting, which could also trigger the development of new organic architectures for photocatalytic overall water splitting through the rational control of surface chemistry.
Co-reporter:Yanjuan Cui, Jianhui Huang, Xianzhi Fu and Xinchen Wang
Catalysis Science & Technology (2011-Present) 2012 - vol. 2(Issue 7) pp:NaN1402-1402
Publication Date(Web):2012/03/29
DOI:10.1039/C2CY20036H
Mesoporous graphitic carbon nitrides were synthesized by a thermal-induced polymerization of NH4SCN on the surface of silica nanoparticles as the templates. The catalysts thus obtained were used as visible light photocatalysts for the degradation of organic pollutants in water. The physicochemical properties of catalysts were characterized by several techniques. The photocatalytic activity of samples was evaluated by the decomposition of chlorophenol and phenol in aqueous phase. Results demonstrated that mesoporous graphitic carbon nitrides can photocatalytically oxidize and eventually mineralize organic pollutants in aqueous solution under visible light irradiation. The photocatalysts can induce the formation of reactive oxy-species such as H2O2, ˙OH and ˙O2−/˙OOH under visible light irradiation, while keeping a high photocatalytic reactivity during recycling operations. The higher activity of mesoporous carbon nitrides compared to nonporous carbon nitride can be attributed to their enlarged surface area and enhanced light-harvesting effect, facilitating the photogeneration of active oxy-radicals in water.
Co-reporter:Fangzheng Su, Markus Antonietti and Xinchen Wang
Catalysis Science & Technology (2011-Present) 2012 - vol. 2(Issue 5) pp:NaN1009-1009
Publication Date(Web):2012/02/15
DOI:10.1039/C2CY00012A
Deprotonated mesoporous graphitic carbon nitride (mpg-C3N4) was achieved by a simple method of treatment of as-prepared materials with different basic aqueous solutions (K2CO3, KOH, tBuOK). The resultant polymeric materials show significantly enhanced basicity, while maintaining the original mesoporous structure. It was then used as a heterogeneous base catalyst for Knoevenagel condensations and transesterification reactions. Catalytic results show that the deprotonated mpg-C3N4 exhibits high efficiency for promoting these reactions as a solid and polymeric catalyst. The reactions between various aldehydes and malonic derivatives, alcohols and β-ketoesters could proceed smoothly in the presence of deprotonated mpg-C3N4. The catalyst could be recycled and reused for several runs without any loss of intrinsic catalytic activity.
Co-reporter:Lihua Lin, Chong Wang, Wei Ren, Honghui Ou, Yongfan Zhang and Xinchen Wang
Chemical Science (2010-Present) 2017 - vol. 8(Issue 8) pp:NaN5511-5511
Publication Date(Web):2017/05/30
DOI:10.1039/C7SC00900C
Photocatalytic water splitting is an ideal pathway to produce hydrogen for the future energy supply due to the sustainability of solar energy and the mild reaction conditions. In the past four decades, many inorganic semiconductor photocatalysts have been studied for this purpose. In recent years, conjugated polymers, in particular covalent carbon nitride frameworks, have rapidly emerged as a new family of photocatalysts. However, the use of conjugated photocatalysts in overall water splitting in the absence of sacrificial agents has been much less reported. Herein, we used surface kinetic control to photocatalyze overall water splitting by a covalent carbon nitride semiconductor with a crystalline poly(triazine imide) (PTI) frameworks. Our study demonstrates that the loading of a Pt co-catalyst on the PTI surface plays the key role in inducing overall water splitting. The co-deposition of a cobalt species can effectively increase the photocatalytic activity and adjust the ratio of H2 and O2 produced, as well as enhancing the stability of the photocatalyst. The optimal sample with the dual co-catalysts shows an apparent quantum yield of 2.1% for the overall water splitting reaction.
Co-reporter:Huanli Wang, Lisha Zhang, Zhigang Chen, Junqing Hu, Shijie Li, Zhaohui Wang, Jianshe Liu and Xinchen Wang
Chemical Society Reviews 2014 - vol. 43(Issue 15) pp:NaN5244-5244
Publication Date(Web):2014/05/20
DOI:10.1039/C4CS00126E
Semiconductor-mediated photocatalysis has received tremendous attention as it holds great promise to address the worldwide energy and environmental issues. To overcome the serious drawbacks of fast charge recombination and the limited visible-light absorption of semiconductor photocatalysts, many strategies have been developed in the past few decades and the most widely used one is to develop photocatalytic heterojunctions. This review attempts to summarize the recent progress in the rational design and fabrication of heterojunction photocatalysts, such as the semiconductor–semiconductor heterojunction, the semiconductor–metal heterojunction, the semiconductor–carbon heterojunction and the multicomponent heterojunction. The photocatalytic properties of the four junction systems are also discussed in relation to the environmental and energy applications, such as degradation of pollutants, hydrogen generation and photocatalytic disinfection. This tutorial review ends with a summary and some perspectives on the challenges and new directions in this exciting and still emerging area of research.
Co-reporter:Jinshui Zhang, Marek Grzelczak, Yidong Hou, Kazuhiko Maeda, Kazunari Domen, Xianzhi Fu, Markus Antonietti and Xinchen Wang
Chemical Science (2010-Present) 2012 - vol. 3(Issue 2) pp:NaN446-446
Publication Date(Web):2011/10/13
DOI:10.1039/C1SC00644D
The search for earth-abundant semiconductors and co-catalysts for water oxidation is an important step towards conversion of solar energy into fuel chemicals in a sustainable manner. Here, we report the integration of Co3O4 nanoparticles within graphitic carbon nitride to construct a nanohybrid photocatalyst made of abundant elements for the photocatalytic generation of oxygen from water, achieving an apparent quantum efficiency of 1.1% at 420 nm for water splitting to oxygen. The present system shows great promise in polymer photocatalysis for applications in future energy cycles based on sustainable materials.
Co-reporter:Dandan Zheng, Chenyang Pang, Yuxing Liu and Xinchen Wang
Chemical Communications 2015 - vol. 51(Issue 47) pp:NaN9709-9709
Publication Date(Web):2015/05/06
DOI:10.1039/C5CC03143E
Incorporation of aromatic motifs into the nanosized shells of hollow carbon nitride nanospheres has been reported to develop functional photosynthetic structures for solar energy application. This modification results in an extended π-conjugation system, red-shift of the optical absorption, and an improved charge separation in the shell, while still retaining the unique hollow polymeric nanoarchitectures. This strategy enables the tuning of the semiconductor properties of the shell substance in the hollow carbon nitride nanostructures to generate the redox species to enhance photocatalytic activity for hydrogen evolution using visible light.
Co-reporter:Guigang Zhang, Zhi-An Lan, Lihua Lin, Sen Lin and Xinchen Wang
Chemical Science (2010-Present) 2016 - vol. 7(Issue 5) pp:NaN3066-3066
Publication Date(Web):2016/01/27
DOI:10.1039/C5SC04572J
We report the direct splitting of pure water by light-excited graphitic carbon nitride (g-C3N4) modified with Pt, PtOx, and CoOx as redox cocatalysts, while pure g-C3N4 is virtually inactive for overall water splitting by photocatalysis. The novelty is in the selective creation of both H2 and O2 cocatalysts on surface active sites of g-C3N4via photodeposition triggering the splitting of water for the simultaneous evolution of H2 and O2 gases in a stoichiometric ratio of 2:1, irradiated with light, without using any sacrificial reagents. The photocatalyst was stable for 510 hours of reaction.
