Co-reporter:Chengyu Mao, Yanxiang Wang, Wei Jiao, Xitong Chen, Qipu Lin, Mingli Deng, Yun Ling, Yaming Zhou, Xianhui Bu, and Pingyun Feng
Langmuir November 28, 2017 Volume 33(Issue 47) pp:13634-13634
Publication Date(Web):November 15, 2017
DOI:10.1021/acs.langmuir.7b02403
Developing photoanodes with efficient visible-light harvesting and excellent charge separation still remains a key challenge in photoelectrochemical water splitting. Here zeolite-type chalcogenide CPM-121 is integrated with TiO2 nanowires to form a heterostructured photoanode, in which crystalline CPM-121 particles serve as a visible light absorber and TiO2 nanowires serve as an electron conductor. Owing to the small band gap of chalcogenides, the hybrid electrode demonstrates obvious absorption in visible-light range. Electrochemical impedance spectroscopy (EIS) shows that electron transport in the hybrid electrode has been significantly facilitated due to the heterojunction formation. A >3-fold increase in photocurrent is observed on the hybrid electrode under visible-light illumination when it is used as a photoanode in a neutral electrolyte without sacrificial agents. This study opens up a new avenue to explore the potential applications of crystalline porous chalcogenide materials for solar-energy conversion in photoelectrochemistry.
Co-reporter:Ya-Pan Wu, Wei Zhou, Wen-Wen Dong, Jun Zhao, Xiu-Qing Qiao, Dong-Fang Hou, Dong-Sheng Li, Qichun Zhang, and Pingyun Feng
Crystal Growth & Design April 5, 2017 Volume 17(Issue 4) pp:2158-2158
Publication Date(Web):March 13, 2017
DOI:10.1021/acs.cgd.7b00102
Because porous metal oxides with controllable morphologies have been attracting much attention for their potential applications in the fields of adsorption/separation, sensing, energy storage, and conversion, it is highly desirable to prepare new morphology of metal oxides and investigate their performance. In this work, CuO particles with different shapes such as octahedron, sponge-like octahedron, and sphere have been synthesized through thermal decomposition of crystalline Cu(II)–organic frameworks (HKUST-1). The structure and morphology of as-prepared CuO particles have been fully characterized by the usage of XRD, XPS, SEM, and TEM. The gas-sensing behaviors of these CuO samples have been investigated and our results show that CuO-400 with spherical shape displays unprecedented high response (maximum value, 102) for triethylamine (TEA) at 100 ppm with a low detection limit of 5 ppm, a lower working temperature (230 °C), excellent reproducibility, and long-term stability. The highly sensing behavior of CuO-400 sphere might be due to its special structural factor with many open active sites for oxygen adsorption, which could react with TEA molecules more efficiently. Our results clearly suggest that porous CuO particles should be promising candidates for future practical application to detect TEA vapor at relatively low temperature.
Co-reporter:Jian Guo;Chengyu Mao;Ruikang Zhang;Mingfei Shao;Min Wei
Journal of Materials Chemistry A 2017 vol. 5(Issue 22) pp:11016-11025
Publication Date(Web):2017/06/06
DOI:10.1039/C7TA00770A
Photoelectrochemical (PEC) water oxidation has received considerable attention owing to its key role in the overall water splitting. In this work, several reduced titania@layered double hydroxide (CoAl–LDH, CoCr–LDH, and CoFe–LDH) hybrid photoanodes were fabricated via electrochemical deposition of LDH on the reduced titania, and their PEC properties for water oxidation were studied systematically. The reduced titania@CoCr–LDH photoanode shows a much improved PEC performance compared with pristine reduced titania, with a photocurrent density enhancement of 43% (from 0.65 mA cm−2 to 0.93 mA cm−2) and an onset potential decrease of 21% (from 0.23 V to 0.18 V vs. the RHE). This improvement is also successfully demonstrated in the reduced titania@CoAl–LDH and reduced titania@CoFe–LDH system. The photoconversion efficiency of reduced titania is significantly enhanced after the incorporation of LDH (0.42–0.51% at ∼0.46 V vs. the RHE). Both the experimental studies and DFT calculations confirm a synergistic effect between the reduced titania and LDH. The results show that a good match of the band structure facilitates the fast electron–hole separation and the migration of holes from reduced titania to LDH, followed by the LDH catalyzed water oxidation. The CoCr–LDH has the highest driving force for oxygen evolution among these LDHs, accounting for the optimal PEC performance of the reduced titania@CoCr–LDH photoanode.
Co-reporter:Qipu Lin;Chengyu Mao;Aiguo Kong;Xianhui Bu;Xiang Zhao
Journal of Materials Chemistry A 2017 vol. 5(Issue 40) pp:21189-21195
Publication Date(Web):2017/10/17
DOI:10.1039/C7TA06658A
The combined use of porphyrins and fluorides to fabricate pillared coordination sheets is presented. Multiple features, such as coordinatively unsaturated metal sites, an optimal pore space, and a fluoride-decorated internal surface, make the new materials ideal adsorbents with high capacity and affinity for carbon dioxide. In addition, the new materials are shown to be suitable single-source precursors to afford fluorine-doped graphene analogues for application in oxygen reduction reaction electrodes.
Co-reporter:Quan-Guo ZhaiXianhui Bu, Xiang ZhaoDong-Sheng Li, Pingyun Feng
Accounts of Chemical Research 2017 Volume 50(Issue 2) pp:
Publication Date(Web):January 20, 2017
DOI:10.1021/acs.accounts.6b00526
ConspectusMetal–organic framework (MOF) materials have emerged as one of the favorite crystalline porous materials (CPM) because of their compositional and geometric tunability and many possible applications. In efforts to develop better MOFs for gas storage and separation, a number of strategies including creation of open metal sites and implantation of Lewis base sites have been used to tune host–guest interactions. In addition to these chemical factors, the geometric features such as pore size and shape, surface area, and pore volume also play important roles in sorption energetics and uptake capacity. For efficient capture of small gas molecules such as carbon dioxide under ambient conditions, large surface area or high pore volume are often not needed. Instead, maximizing host–guest interactions or the density of binding sites by encaging gas molecules in snug pockets of pore space can be a fruitful approach. To put this concept into practice, the pore space partition (PSP) concept has been proposed and has achieved a great experimental success. In this account, we will highlight many efforts to implement PSP in MOFs and impact of PSP on gas uptake performance.In the synthetic design of PSP, it is helpful to distinguish between factors that contribute to the framework formation and factors that serve the purpose of PSP. Because of the need for complementary structural roles, the synthesis of MOFs with PSP often involves multicomponent systems including mixed ligands, mixed inorganic nodes, or both. It is possible to accomplish both framework formation and PSP with a single type of polyfunctional ligands that use some functional groups (called framework-forming group) for framework formation and the remaining functional groups (called pore-partition group) for PSP. Alternatively, framework formation and PSP can be shouldered by different chemical species. For example, in a mixed-ligand system, one ligand (called framework-forming agent) can play the role of the framework formation while the other type of ligand (called pore-partition agent) can assume the role of PSP.PSP is sensitive to the types of inorganic secondary building units (SBUs). The coexistence of SBUs complementary in charge, connectivity, and so on can promote PSP. The use of heterometallic systems can promote the diversity of SBUs coexistent under a given condition. Heterometallic system with metal ions of different oxidation states also provides the charge tunability of SBUs and the overall framework, providing an additional level of control in self-assembly and ultimately in the materials’ properties. Of particular interest is the PSP in MIL-88 type (acs-type topology) structure, which has led to a huge family of CPMs (called pacs CPMs, pacs = partitioned acs) exhibiting low isosteric heat of adsorption and yet superior CO2 uptake capacity.
Co-reporter:Yuan Wang;Xitong Chen;Qipu Lin;Aiguo Kong;Quan-Guo Zhai;Shilei Xie
Nanoscale (2009-Present) 2017 vol. 9(Issue 2) pp:862-868
Publication Date(Web):2017/01/05
DOI:10.1039/C6NR07268B
High levels of iron–nitrogen doped porous carbon materials are obtained from MOF-253 using a step-by-step post-synthetic modification strategy. MOF-253 possessing open 2,2′-bipyridine nitrogen sites not only serves as a precursor but also provides chelate bonding sites for Fe2+. Followed by further impregnation of 1,10-phenanthroline, high surface area porous carbon materials are obtained. For comparison, when iron-1,10-phenanthroline species as a whole are incorporated into MOF-253, carbon materials with less active sites and low surface area are obtained. The porous carbon materials derived from MOF-253 by using a step-by-step post-synthetic modification strategy demonstrate excellent ORR activity, high selectivity (direct 4e− reduction of oxygen to water) and stability under both alkaline and acidic conditions. The onset potential of the porous carbon material under alkaline conditions (980 mV) is the same as that of Pt/C (20 wt%) (980 mV) and the half-wave potential (E1/2) is 840 mV, which is 20 mV more than that of Pt/C (20 wt%). Under acidic conditions, the onset potential and the half-wave potential are only 20 mV and 30 mV less than those of Pt/C (20 wt%). The developed step-by-step post-synthetic modification route of MOFs has expanded the ways to prepare functionalized porous carbon for energy related applications.
Co-reporter:Hai Yang;Liangyong Mei;Pengcheng Wang;Joseph Genereux;Yinsheng Wang;Bing Yi;Chaktong Au;Limin Dang
RSC Advances (2011-Present) 2017 vol. 7(Issue 72) pp:45721-45732
Publication Date(Web):2017/09/22
DOI:10.1039/C7RA09022F
Reduced TiO2 (TiO2−X) materials with different crystallographic structures were prepared and characterized. Cat.I-A, Cat.II-R, Cat.III-B are TiO2−X with anatase, rutile and brookite structures, respectively, while the Cat.IV-A&R series are materials with anatase and rutile phases mixed in different ratios. All samples exhibit efficient photocatalytic activity for the degradation of norfloxacin (Nor) under visible light, and Cat.IV-A&R-4 is the best among the samples studied. Our results show that the photocatalytic activity is governed by different factors such as the specific surface area of the catalysts as well as the concentrations of Ti3+ and the density of oxygen vacancies in the photocatalytic materials. Mechanistic study of the materials demonstrates that photohole (h+) transfer contributes more to Nor degradation than reaction with ˙OH radicals and the other reactive oxygen species (ROSs). Intermediate species were characterized by HPLC-TOF-HRMS and HPLC-MS/MS to construct a general transformation mechanism of Nor on the family of TiO2−X under visible light. The study shows that Nor adsorption onto TiO2−X occurs by its heteroatoms followed by cleavage of its piperazine ring and hydroxylation of its quinolone ring under the attack of h+ and ˙OH radicals. The study could assist the further search for efficient photocatalytic materials for the degradation of organic pollutants.
Co-reporter:Quan-Guo Zhai; Xianhui Bu; Chengyu Mao; Xiang Zhao
Journal of the American Chemical Society 2016 Volume 138(Issue 8) pp:2524-2527
Publication Date(Web):February 19, 2016
DOI:10.1021/jacs.5b13491
Despite their having much greater potential for compositional and structural diversity, heterometallic metal–organic frameworks (MOFs) reported so far have lagged far behind their homometallic counterparts in terms of CO2 uptake performance. Now the power of heterometallic MOFs is in full display, as shown by a series of new materials (denoted CPM-200s) with superior CO2 uptake capacity (up to 207.6 cm3/g at 273 K and 1 bar), close to the all-time record set by MOF-74-Mg. The isosteric heat of adsorption can also be tuned from −16.4 kJ/mol for CPM-200-Sc/Mg to −79.6 kJ/mol for CPM-200-V/Mg. The latter value is the highest reported for MOFs with Lewis acid sites. Some members of the CPM-200s family consist of combinations of metal ions (e.g., Mg/Ga, Mg/Fe, Mg/V, Mg/Sc) that have never been shown to coexist in any known crystalline porous materials. Such previously unseen combinations become reality through a cooperative crystallization process, which leads to the most intimate form of integration between even highly dissimilar metals, such as Mg2+ and V3+. The synergistic effects of heterometals bestow CPM-200s with the highest CO2 uptake capacity among known heterometallic MOFs and place them in striking distance of the all-time CO2 uptake record.
Co-reporter:Xiang Zhao, Xianhui Bu, Edward T. Nguyen, Quan-Guo Zhai, Chengyu Mao, and Pingyun Feng
Journal of the American Chemical Society 2016 Volume 138(Issue 46) pp:15102-15105
Publication Date(Web):November 14, 2016
DOI:10.1021/jacs.6b07901
Pore space partition, especially the one using C3-symmetric 2,4,6-tri(4-pyridyl)-1,3,5-triazine as pore-partition agent in MIL-88 type (the acs net), has been shown to dramatically enhance CO2 uptake to near-record values. The continued advance in property engineering via pore space partition would depend on intelligent design of both framework components and pore-partition agent. Here, we report a new advance in the design of pore-partition agent by demonstrating a symmetry-guided pathway to develop a large variety of di- and trinuclear 1,2,4-triazolate-based clusters for use as pore-partition agent. The use of metal–organic clusters (instead of organic ligands) as pore-partition agent gives rise to many new pore-partitioned materials with huge compositional variety. The full assembly involves the simultaneous formation of two separate coordination architectures (i.e., the 3-D acs framework and 0-D triazolate clusters) and the eventual welding between the acs framework and triazolate clusters. The wide range of new compositions and structures provides a high degree of tunability in gas sorption properties.
Co-reporter:Koroush Sasan, Qipu Lin, Chengyu Mao and Pingyun Feng
Nanoscale 2016 vol. 8(Issue 21) pp:10913-10916
Publication Date(Web):17 May 2016
DOI:10.1039/C6NR02525K
Open framework metal chalcogenides are a family of porous semiconducting materials with diverse chemical compositions. Here we show that these materials containing covalent three-dimensional superlattices of nanosized supertetrahedral clusters can function as efficient photocatalysts for the reduction of CO2 to CH4. Unlike dense semiconductors, metal cations are successfully incorporated into the channels of the porous semiconducting materials to further tune the physical properties of the materials such as electrical conductivity and band gaps. In terms of the photocatalytic properties, the metal-incorporated porous chalcogenides demonstrated enhanced solar energy absorption and higher electrical conductivity and improved photocatalytic activity.
Co-reporter:Xitong Chen, Xianhui Bu, Qipu Lin, Quan-Guo Zhai, Xiang Zhao, Yuan Wang, and Pingyun Feng
Crystal Growth & Design 2016 Volume 16(Issue 11) pp:6531
Publication Date(Web):October 11, 2016
DOI:10.1021/acs.cgd.6b01229
Metal–organic frameworks based on lithium inherit the unique chemical and structural features of the metal ion itself. While the monomeric lithium node, usually 4-connected, is very desirable for designing zeolite-type networks, the resulting lithium MOF usually has limited stability, especially for 3-connected nets due to the solvent termination. The conventional design strategy based on lithium aryloxide clusters makes use of phenol-type ligands for cluster formation and a separate bifunctional ligand for cross-linking, which also leads to 4-connected nets. By integrating the roles of cluster-formation and framework-formation into a single ligand, 4-hydroxypyridine was previously shown to give a highly stable 8-connected framework. Still, its shortness and rigidity limit both the porosity and the type of framework topologies. In this work, we demonstrate the new chemical and structural features of lithium cubane clusters with an elongated ligand, which results in two high-connected 3-D framework materials characterized by self-penetration and self-polymerization, respectively, unlike the commonly observed interpenetration. Such a method provides a feasible path to tune both stability and porosity in lithium-based MOFs.
Co-reporter:Quan-Guo Zhai, Xianhui Bu, Xiang Zhao, Chengyu Mao, Fei Bu, Xitong Chen, and Pingyun Feng
Crystal Growth & Design 2016 Volume 16(Issue 3) pp:1261
Publication Date(Web):February 10, 2016
DOI:10.1021/acs.cgd.5b01297
While synthesis of materials with novel topologies is important, it can be even more impactful to create new modular structural units capable of serving as a versatile pool of connectors for rational design of targeted solids. Here we report five magnesium–organic frameworks (denoted as CPM-201 to -205) exhibiting step-by-step evolution of trimeric clusters from unprecedented core-less [Mg3(COO)6], to OH-centered [Mg3(μ3-OH)(COO)6]−, and eventually to two variations of pentamers [Mg5(μ3-OH)2(COO)8] formed from fusion of trimers. New clusters are joined by dicarboxylates into trigonal-bipyramidal, cuboidal, and octahedral cages embedded in the labyrinth of hexagonal and cubic channels. These materials exhibit high CO2 uptake and CO2/CH4 selectivity.
Co-reporter:Huajun Yang, Min Luo, Li Luo, Hongxiang Wang, Dandan Hu, Jian Lin, Xiang Wang, Yanlong Wang, Shuao Wang, Xianhui Bu, Pingyun Feng, and Tao Wu
Chemistry of Materials 2016 Volume 28(Issue 23) pp:
Publication Date(Web):November 16, 2016
DOI:10.1021/acs.chemmater.6b04273
The safe use of nuclear energy requires the development of advanced adsorbent technology to address environment damage from nuclear waste or accidental release of radionuclides. Recently developed amine-directed chalcogenide frameworks have intrinsic advantages as ion-exchange materials to capture radionuclides, because their exceptionally negative framework charge can lead to high cation-uptake capacity and their 3-D multidimensional intersecting channel promotes rapid ion diffusion and offer a unique kinetic advantage. Prior to this work, however, such advantages could not be realized because organic cations in the as-synthesized materials are sluggish during ion exchange. Here we report an ingenious approach on the activation of amine-directed zeolitic chalcogenides through a stepwise ion-exchange strategy and their use in cesium adsorption. The activated porous chalcogenide exhibits highly enhanced cesium uptake compared to the pristine form and is comparable to the best metal chalcogenide sorbents so far. Further ion-exchange experiments in the presence of competing ions confirm the high selectivity for cesium ions. Excellent removal performance has also been observed in real water samples, highlighting the importance of stepwise ion exchange strategy to activate amine-directed chalcogenide framework for 137Cs+ removal.
Co-reporter:Jian Lin, Dan-Dan Hu, Qian Zhang, Dong-Sheng LiTao Wu, Xianhui BuPingyun Feng
The Journal of Physical Chemistry C 2016 Volume 120(Issue 51) pp:29390-29396
Publication Date(Web):December 12, 2016
DOI:10.1021/acs.jpcc.6b09126
Solid-state red phosphors of Mn2+-doped nanocrystals usually suffer from poor intensity. While the d–d emission of Mn2+ in yellow window has been extensively studied, shift toward lower energy remains challenging. Typically, intrinsic surface defects and self-purification of dopants are two obstacles for enhancing the intensity of red emission. Moreover, for red phosphors Mn2+ ions also need an appropriate host matrix and environment. Through an in situ doping strategy and optimization of the Mn2+ doping level, intense red-emitting Mn2+ dopant emission is reported here for MnCdInS@InS host. The doping strategy allows doping of Mn2+ at the core and/or surface sites of supertetrahedral “core–shell” nanocluster (Mn@MnCdInS@InS), leading to the red emission (at 643 nm) with over 40% quantum yield. Moreover, systematic control of doping level results in a series of crystalline Mn2+-doped materials with tunable photoluminescence quantum yield. In addition to the synthesis of an important class of red-emitting materials rarely obtained from Mn2+ doping, details of the physical chemistry associated with the doping process are probed with the new fundamental findings reported here.
Co-reporter:Qipu Lin;Xianhui Bu;Aiguo Kong;Chengyu Mao;Fei Bu
Advanced Materials 2015 Volume 27( Issue 22) pp:3431-3436
Publication Date(Web):
DOI:10.1002/adma.201500727
Co-reporter:Xiang Zhao; Xianhui Bu; Quan-Guo Zhai; Huy Tran
Journal of the American Chemical Society 2015 Volume 137(Issue 4) pp:1396-1399
Publication Date(Web):January 26, 2015
DOI:10.1021/ja512137t
Metal–organic frameworks (MOFs) with the highest CO2 uptake capacity are usually those equipped with open metal sites. Here we seek alternative strategies and mechanisms for developing high-performance CO2 adsorbents. We demonstrate that through a ligand insertion pore space partition strategy, we can create crystalline porous materials (CPMs) with superior CO2 uptake capacity. Specifically, a new material, CPM-33b-Ni without any open metal sites, exhibits the CO2 uptake capacity comparable to MOF-74 with the same metal (Ni) at 298 K and 1 bar.
Co-reporter:Qipu Lin; Xianhui Bu; Chengyu Mao; Xiang Zhao; Koroush Sasan
Journal of the American Chemical Society 2015 Volume 137(Issue 19) pp:6184-6187
Publication Date(Web):May 7, 2015
DOI:10.1021/jacs.5b03550
High-silica zeolites, as exemplified by ZSM-5, with excellent chemical and thermal stability, have generated a revolution in industrial catalysis. In contrast, prior to this work, high-silica-zeolite-like chalcogenides based on germanium/tin remained unknown, even after decades of research. Here six crystalline high-germanium or high-tin zeolite-type sulfides and selenides with four different topologies are reported. Their unprecedented framework compositions give these materials much improved thermal and chemical stability with high surface area (Langmuir surface area of 782 m2/g–1) comparable to or better than zeolites. Among them, highly stable CPM-120-ZnGeS allows for ion exchange with diverse metal or complex cations, resulting in fine-tuning in porosity, fast ion conductivity, and photoelectric response. Being among the most porous crystalline chalcogenides, CPM-120-ZnGeS (exchanged with Cs+ ions) also shows reversible adsorption with high capacity and affinity for CO2 (98 and 73 cm3 g–1 at 273 and 298 K, respectively, isosteric heat of adsorption = 40.05 kJ mol–1). Moreover, CPM-120-ZnGeS could also function as a robust photocatalyst for water reduction to generate H2. The overall activity of H2 production from water, in the presence of Na2S–Na2SO3 as a hole scavenger, was 200 μmol h–1/(0.10 g). Such catalytic activity remained undiminished under illumination by UV light for as long as measured (200 h), demonstrating excellent resistance to photocorrosion even under intense UV radiation.
Co-reporter:Qipu Lin; Xianhui Bu; Aiguo Kong; Chengyu Mao; Xiang Zhao; Fei Bu
Journal of the American Chemical Society 2015 Volume 137(Issue 6) pp:2235-2238
Publication Date(Web):February 4, 2015
DOI:10.1021/jacs.5b00076
Four cubic zirconium-porphyrin frameworks, CPM-99(H2, Zn, Co, Fe), were synthesized by a molecular-configuration-guided strategy. Augmentation of meso-substituted side arms (with double-torsional biphenyl rings) of tetratopic porphyrin linkers leads to a successful implementation of zirconium-carboxylate frameworks with cubic 2.5 nm cage. The hard-templating effect of Zr6-polyoxo-cluster and uniformly embedded (metallo)porphyrin centers endow CPM-99 with highly desirable properties as precursors for oxygen reduction reaction (ORR) catalysts. The pyrolytic products not only retain the microcubic morphology of the parent CPM-99 but also possess porphyrinic active sites, hierarchical porosity, and highly conducting networks. CPM-99Fe-derived material, denoted CPM-99Fe/C, exhibits the best ORR activity, comparable to benchmark 20% Pt/C in alkaline and acidic media, but CPM-99Fe/C is more durable and methanol-tolerant. This work demonstrates a new route for the development of nonprecious metal ORR catalysts from stable metalloporphyrinic MOFs.
Co-reporter:Yuan Wang, Aiguo Kong, Xitong Chen, Qipu Lin, and Pingyun Feng
ACS Catalysis 2015 Volume 5(Issue 6) pp:3887
Publication Date(Web):April 20, 2015
DOI:10.1021/acscatal.5b00530
Hierarchical porous carbon nanoshells with about 40 nm cavities are synthesized by using CdS@mSiO2 core–shell structured materials as hard templates and 4,4′-bipyridine and FeCl3·6H2O as nitrogen, carbon, and iron sources. CdS@mSiO2 denotes a CdS nanoparticle core and mesoporous SiO2 (mSiO2) shell. The obtained porous and hollow carbon nanoshells demonstrate excellent electrocatalytic activity for oxygen reduction reaction (ORR). Both the onset potential (0.98 V) and half-wave potential (0.85 V) are more positive than that of commercial Pt/C in alkaline conditions with the same catalyst loading (0.1 mg cm–2). In acidic conditions, the onset and half-wave potentials of carbon-nanoshell electrodes are only 30 and 20 mV less than that of commercial Pt/C, respectively. The outstanding stability and electrocatalytic activity for ORR of these novel carbon nanoshells can be attributed to the use of a Fe–Nx containing precursor, hierarchical porous structural features, and perhaps most importantly the hollow shell design. Such hollow carbon nanoshells exhibit high performance as electrocatalysts for ORR; also this synthetic approach represents a versatile, new route toward the preparation of efficient materials with hierarchical porous and hollow structural features.Keywords: carbon-nanoshell; nanoparticles; nonprecious metal catalyst; oxygen reduction; porous structure
Co-reporter:Chengyu Mao, Aiguo Kong, Yuan Wang, Xianhui Bu and Pingyun Feng
Nanoscale 2015 vol. 7(Issue 24) pp:10817-10822
Publication Date(Web):03 Jun 2015
DOI:10.1039/C5NR02346G
The use of metal–organic frameworks (MOFs) as templates and precursors to synthesize new carbon materials with controllable morphology and pre-selected heteroatom doping holds promise for applications as efficient non-precious metal catalysts. Here, we report a facile pyrolysis pathway to convert MIL-100 into nitrogen-doped carbon shells encapsulating Fe nanoparticles in a comparative study involving multiple selected nitrogen sources. The hierarchical porous architecture, embedded Fe nanoparticles, and nitrogen decoration endow this composite with a superior oxygen reduction activity. Furthermore, the excellent durability and high methanol tolerance even outperform the commercial Pt–C catalyst.
Co-reporter:Koroush Sasan, Fan Zuo, Yuan Wang and Pingyun Feng
Nanoscale 2015 vol. 7(Issue 32) pp:13369-13372
Publication Date(Web):07 Jul 2015
DOI:10.1039/C5NR02974K
Self-doped TiO2 shows visible light photocatalytic activity, while commercial TiO2 (P25) is only UV responsive. The incorporation of Ti3+ into TiO2 structures narrows the band gap (2.90 eV), leading to significantly increased photocatalytic activity for the reduction of CO2 into a renewable hydrocarbon fuel (CH4) in the presence of water vapour under visible light irradiation.
Co-reporter:Lijuan Shen, Mingbu Luo, Linjuan Huang, Pingyun Feng, and Ling Wu
Inorganic Chemistry 2015 Volume 54(Issue 4) pp:1191-1193
Publication Date(Web):January 16, 2015
DOI:10.1021/ic502609a
We demonstrate a facile and general approach for the fabrication of highly dispersed Au, Pd, and Pt nanoparticles (NPs) on MIL-125(Ti) without using extra reducing and capping agents. Noble-metal NP formation is directed by an in situ redox reaction between the reductive MIL-125(Ti) with Ti3+ and oxidative metal salt precursors. The resulting composites function as efficient photocatalysts.
Co-reporter:Quan-Guo Zhai, Ni Bai, Shu’ni Li, Xianhui Bu, and Pingyun Feng
Inorganic Chemistry 2015 Volume 54(Issue 20) pp:9862-9868
Publication Date(Web):October 2, 2015
DOI:10.1021/acs.inorgchem.5b01611
In the design of new materials, those with rare and exceptional compositional and structural features are often highly valued and sought after. On the other hand, materials with common and more accessible modes can often provide richer and unsurpassed compositional and structural variety that makes them a more suitable platform for systematically probing the composition–structure–property correlation. We focus here on one such class of materials, pillar-layered metal–organic frameworks (MOFs), because different pore size and shape as well as functionality can be controlled and adjusted by using pillars with different geometrical and chemical features. Our approach takes advantage of the readily accessible layered Zn-1,2,4-triazolate motif and diverse dicarboxylate ligands with variable length and functional groups, to prepare seven Zn-triazolate-dicarboxylate pillar-layered MOFs. Six different gases (N2, H2, CO2, C2H2, C2H4, and CH4) were used to systematically examine the dependency of gas sorption properties on chemical and geometrical properties of those MOFs as well as their potential applications in gas storage and separation. All of these pillar-layered MOFs show not only remarkable CO2 uptake capacity, but also high CO2 over CH4 and C2 hydrocarbons over CH4 selectivity. An interesting observation is that the BDC ligand (BDC = benzenedicarboxylate) led to a material with the CO2 uptake outperforming all other metal-triazolate-dicarboxylate MOFs, even though most of them are decorated with amino groups, generally believed to be a key factor for high CO2 uptake. Overall, the data show that the exploration of the synergistic effect resulting from combined tuning of functional groups and pore size may be a promising strategy to develop materials with the optimum integration of geometrical and chemical factors for the highest possible gas adsorption capacity and separation performance.
Co-reporter:Dong-Sheng Liu, Yan Sui, Wen-Tong Chen, and Pingyun Feng
Crystal Growth & Design 2015 Volume 15(Issue 8) pp:4020
Publication Date(Web):June 25, 2015
DOI:10.1021/acs.cgd.5b00637
Two new zinc compounds, [Zn2(mtz)(nic)2(OH)]n·0.5nH2O (1) and [Zn(phtz)(nic)]2n (2) (Hmtz = 5-methyltetrazole, Hphtz = 5-phenyltetrazole, Hnic = nicotinic acid), have been synthesized by a dual-ligand approach under solvothermal conditions. The compounds were characterized by single-crystal X-ray diffraction, elemental analysis, and infrared spectroscopy, respectively. The X-ray diffraction analysis reveals that both compounds exhibit a noncentrosymmetric polar packing arrangement. Compound 1 is a 3D framework constructed from the zigzag chain subunits of [Zn(nic)]+ with a 4-connected “irl” topology. Compound 2 possesses a 2D 4-connected ‘“sql” topology constructed from the linear chain subunit of [Zn(nic)]+, which are linked together with phtz– ligands. Impressively, both of the two compounds display second-harmonic generation response and ferroelectric behaviors. Furthermore, the photoluminescence of the compounds was also investigated.
Co-reporter:Fei Bu, Qipu Lin, Quan-Guo Zhai, Xianhui Bu and Pingyun Feng
Dalton Transactions 2015 vol. 44(Issue 38) pp:16671-16674
Publication Date(Web):20 Aug 2015
DOI:10.1039/C5DT02861B
By using the same ligand, 2,5-furandicarboxylic acid (FDA), and varying synthetic conditions (especially the In3+/FDA ratio), it is possible to access three unique building blocks of indium, demonstrating charge-switching from a positive trimer to a negative monomer and leading to the synthesis of In-MOFs with tunable framework charge.
Co-reporter:Aiguo Kong, Chengyu Mao, Qipu Lin, Xiao Wei, Xianhui Bu and Pingyun Feng
Dalton Transactions 2015 vol. 44(Issue 15) pp:6748-6754
Publication Date(Web):26 Jan 2015
DOI:10.1039/C4DT03726J
By one-step pyrolysis of a unique “cage-in-cage” cobalt metal–organic framework, nitrogen-doped carbon cubes embedded with numerous metallic Co nanoparticles were obtained. A considerable amount of Co particles was encapsulated in thin carbon shells and formed the core–shell-like Co@C structure. With about 60 wt% Co particles in the prepared sample, the nanocomposites of Co nanoparticles and nitrogen-doped carbon show electrocatalytic activity for the oxygen reduction reaction (ORR) with an efficiency comparable to the commercial Pt/C catalyst, but with better durability and methanol-tolerance performance. The metallic Co nanoparticles were found to play an important role in enhancing the ORR activity of the nanocomposites. This simple one-step pyrolysis method provides a novel synthetic route for the synthesis of core–shell-like Co@C nano-composites. The synthesized material represents a highly active non-precious metal catalyst for ORR.
Co-reporter:Koroush Sasan
The Journal of Physical Chemistry C 2015 Volume 119(Issue 24) pp:13545-13550
Publication Date(Web):June 2, 2015
DOI:10.1021/acs.jpcc.5b04017
Nitrogen–sulfur–iron-doped porous carbon material with high surface area (1026 m2 g–1) and large pore size is synthesized by the pyrolysis of hemoglobin, an abundant and inexpensive natural compound, with mesoporous silica foam (MS) as a template and thiocarbamide (TCA) as an additional sulfur source in an argon atmosphere. Our results indicated that as compared to the commercial 20% Pt/C catalyst, the synthesized catalyst exhibits not only higher current density and stability but also higher tolerance to crossover chemicals. More importantly, the synthetic method is simple and inexpensive.
Co-reporter:Jian Lin ; Qian Zhang ; Le Wang ; Xiaochun Liu ; Wenbo Yan ; Tao Wu ; Xianhui Bu
Journal of the American Chemical Society 2014 Volume 136(Issue 12) pp:4769-4779
Publication Date(Web):March 13, 2014
DOI:10.1021/ja501288x
We report a simple and yet effective method to introduce Mn2+ ions into semiconducting nanoclusters with atomically precise control. Our method utilizes one type of micrometer-sized crystals, composed of well-defined isolated supertetrahedral chalcogenide nanoclusters (∼2 nm, [Cd6In28S52(SH)4]) whose core metal site is unoccupied in as-synthesized pristine form. This unique model structure with vacant core site makes it possible to achieve ordered distribution of Mn2+ dopants, and at the same time effectively preclude the formation of Mn2+ clusters in the host matrix. A two-step synthesis strategy is applied to realize an atomically precise doping of Mn2+ ion into the core site of the nanoclusters, and to achieve uniform distribution of Mn2+ dopants in the crystal lattice. The PL, X-ray photoelectron (XPS), as well as the electron paramagnetic resonance (EPR) spectra reveal the successful incorporation of Mn2+ ion into the core site of the nanocluster. Different from the pristine host material with weak green emission (∼490 nm), the Mn2+-doped material shows a strong red emission (630 nm at room temperature and 654 nm at 30 K), which is significantly red-shifted relative to the orange emission (∼585 nm) observed in traditional Mn2+-doped II–VI semiconductors. Various experiments including extensive synthetic variations and PL dynamics have been performed to probe the mechanistic aspects of synthesis process and resultant unusual structural and PL properties. The quaternary semiconductor material reported here extends the emission window of Mn2+-doped II–VI semiconductor from yellow-orange to red, opening up new opportunities in applications involving photonic devices and bioimaging.
Co-reporter:Chengyu Mao ; Ryan A. Kudla ; Fan Zuo ; Xiang Zhao ; Leonard J. Mueller ; Xianhui Bu
Journal of the American Chemical Society 2014 Volume 136(Issue 21) pp:7579-7582
Publication Date(Web):May 16, 2014
DOI:10.1021/ja5030723
Metal–organic frameworks (MOFs) with cationic frameworks and mobile anions have many applications from sensing, anion exchange and separation, to fast ion conductivity. Despite recent progress, the vast majority of MOFs have neutral frameworks. A common mechanism for the formation of neutral frameworks is the attachment of anionic species such as F– or OH– to the framework metal sites, neutralizing an otherwise cationic scaffolding. Here, we report a general method capable of converting such neutral frameworks directly into cationic ones with concurrent generation of mobile anions. Our method is based on the differential affinity between distinct metal ions with framework anionic species. Specifically, Al3+ is used to strip F– anions away from framework Cr3+ sites, leading to cationic frameworks with mobile Cl– anions. The subsequent anion exchange with OH– further leads to a porous network with mobile OH– anions. New materials prepared by anion stripping can undergo ion exchange with anionic organic dyes and also exhibit much improved ionic conductivity compared to the original unmodified MOFs.
Co-reporter:Xiang Zhao, Chengyu Mao, Xianhui Bu, and Pingyun Feng
Chemistry of Materials 2014 Volume 26(Issue 8) pp:2492
Publication Date(Web):April 7, 2014
DOI:10.1021/cm500473f
Co-reporter:Aiguo Kong, Qipu Lin, Chengyu Mao, Xianhui Bu and Pingyun Feng
Chemical Communications 2014 vol. 50(Issue 98) pp:15619-15622
Publication Date(Web):31 Oct 2014
DOI:10.1039/C4CC06867J
By one-step pyrolysis of an indium–MOF with entrapped cobalt dimers in the presence of melamine, heterometallic carbide nanoparticles (Co3InC0.75) embedded in nitrogen-enriched carbon have been prepared and found to exhibit efficient electrocatalytic activity for oxygen reduction reaction with high durability and methanol-tolerance properties.
Co-reporter:Qipu Lin, Xianhui Bu and Pingyun Feng
Chemical Communications 2014 vol. 50(Issue 31) pp:4044-4046
Publication Date(Web):27 Feb 2014
DOI:10.1039/C4CC00583J
A new super-supertetrahedral cluster, resembling a coreless supertetrahedral T6 cluster, was made as a tin oxyselenide by integrating hard and soft Lewis bases (O2− and Se2−) into the tetravalent system. Its hierarchical architecture, built from supertetrahedral T3-[Sn10O4Se20] and Sn2Se6 clusters, represents a new level of complexity in the cluster-based construction. Compared to pure tin selenides, the new tin oxyselenide material in this work shows much enhanced stability and size-dependent band energy level.
Co-reporter:Koroush Sasan, Qipu Lin, ChengYu Mao and Pingyun Feng
Chemical Communications 2014 vol. 50(Issue 72) pp:10390-10393
Publication Date(Web):25 Jul 2014
DOI:10.1039/C4CC03946G
A new biomimetic heterogeneous photocatalyst ([FeFe]@ZrPF) has been synthesized through the incorporation of homogeneous complex 1 [(í-SCH2)2NC(O)C5H4N]–[Fe2(CO)6] into the highly robust zirconium-porphyrin based metal–organic framework (ZrPF). The immobilized biomimetic [Fe2S2] catalyst inside the MOF shows great improvement in hydrogen generation compared to the reference homogeneous catalyst complex 1.
Co-reporter:Qipu Lin, Zhenyu Zhang, Xianhui Bu, and Pingyun Feng
Inorganic Chemistry 2014 Volume 53(Issue 24) pp:13207-13211
Publication Date(Web):November 26, 2014
DOI:10.1021/ic502527g
Metal chalcogenides based on heterometallic Ge–Cu–S offer dual attractive features of lattice stabilization by high-valent Ge4+ and band gap engineering into solar region by low-valent Cu+. Herein via cationic amine intercalation, we present three new copper-rich materials with the Cu-to-Ge ratio as high as 3. Two different patterns of Cu–Ge–S distribution could be achieved within each honeycomb sheet. The decoration of such honeycomb sheet by −Cu−S− chain or self-coupling between two honeycomb sheets leads to two layer configurations with different thickness and band gaps. The band gap of these new phases (2.06–2.30 eV), tuned by the layer thickness and the Cu/Ge ratio, represents a significant red shift over known Cu–Ge–S phases with lower Cu/Ge ratios.
Co-reporter:Fan Zuo, Le Wang, Pingyun Feng
International Journal of Hydrogen Energy 2014 Volume 39(Issue 2) pp:711-717
Publication Date(Web):13 January 2014
DOI:10.1016/j.ijhydene.2013.10.120
•Quantitatively characterization of Ti3+ concentration was achieved.•Fine-tuning of Ti3+ doping level and phase composition succeeded.•Effect of Ti3+ concentration on photocatalytic activity was studied and explained.•Crucial steps in combustion process were proposed and confirmed by experiments.Self-doped TiO2 shows visible light photocatalytic activity, while pristine TiO2 is only UV responsive. Ti3+ has been demonstrated to be responsible for this improvement. We systematically studied various experimental parameters, such as the amount of reducing agent imidazole, types of imidazoles and Ti sources, and determined effects of these parameters on the combustion process and final materials. The phase composition, Ti3+ concentration, light absorption, surface area, and crystallinity of the product are significantly affected by the amount of imidazoles. Through comparing different imidazoles, we found that only flammable/combustible imidazoles are able to convert Ti4+ into Ti3+. This result is very helpful in understanding the mechanism and reactions in combustion process. Titanium precursors also have a great influence in production of Ti3+ doped TiO2 materials. Titanium alkoxides allow the successful synthesis of blue partially reduced TiO2, while TiCl4 only lead to white pristine TiO2.
Co-reporter:Dr. Shijing Liang;Linrui Wen;Dr. Sen Lin;Dr. Jinhong Bi; Pingyun Feng; Xianzhi Fu; Ling Wu
Angewandte Chemie International Edition 2014 Volume 53( Issue 11) pp:2951-2955
Publication Date(Web):
DOI:10.1002/anie.201311280
Abstract
Monolayer HNb3O8 2D nanosheets have been used as highly chemoselective and active photocatalysts for the selective oxidation of alcohols. The nanosheets exhibit improved photocatalytic activity over their layered counterparts. Results of in situ FTIR, DRS, ESR, and DFT calculations show the formation of surface complexes between the Lewis acid sites on HNb3O8 2D nanosheets and alcohols. These complexes play a key role in the photocatalytic activity of the material. Furthermore, the unique structural features of the nanosheets contributed to their high photocatalytic activity. An electron transition from the coordinated alcohol species to surface Nb atoms takes place and initiates the aerobic oxidation of alcohols with high product selectivity under visible light irradiation. This reaction process is distinct from that of classic semiconductor photocatalysis.
Co-reporter:Chengyu Mao;Dr. Fan Zuo;Dr. Yang Hou; Xianhui Bu; Pingyun Feng
Angewandte Chemie 2014 Volume 126( Issue 39) pp:10653-10657
Publication Date(Web):
DOI:10.1002/ange.201406017
Abstract
A new synthetic method to fabricate Ti3+-modified, highly stable TiO2 photoanodes for H2O oxidation is reported. With Ti foil as both the conducting substrate and the Ti3+/Ti4+ source, one-dimensional blue Ti3+/TiO2 crystals were grown by a one-step hydrothermal reaction. The concentration of Ti3+ was further tuned by N2H4 reduction, leading to a greater photoelectrocatalytic activity, as evidenced by a high photocurrent density of 0.64 mA cm−2 at 1.0 V vs RHE under simulated AM 1.5 G illumination. Electron paramagnetic resonance and Mott–Schottky plots reveal that higher charge-carrier density owing to N2H4 reduction contributes to the observed improvement. The generality of this synthesis method was demonstrated by its effectiveness in improving the performance of other types of photoanodes. By integrating the advantages of the 1D TiO2 architecture with those of Ti3+ self-doping, this work provides a versatile tool toward the fabrication of efficient TiO2 photoanodes.
Co-reporter:Dr. Shijing Liang;Linrui Wen;Dr. Sen Lin;Dr. Jinhong Bi; Pingyun Feng; Xianzhi Fu; Ling Wu
Angewandte Chemie 2014 Volume 126( Issue 11) pp:2995-2999
Publication Date(Web):
DOI:10.1002/ange.201311280
Abstract
Monolayer HNb3O8 2D nanosheets have been used as highly chemoselective and active photocatalysts for the selective oxidation of alcohols. The nanosheets exhibit improved photocatalytic activity over their layered counterparts. Results of in situ FTIR, DRS, ESR, and DFT calculations show the formation of surface complexes between the Lewis acid sites on HNb3O8 2D nanosheets and alcohols. These complexes play a key role in the photocatalytic activity of the material. Furthermore, the unique structural features of the nanosheets contributed to their high photocatalytic activity. An electron transition from the coordinated alcohol species to surface Nb atoms takes place and initiates the aerobic oxidation of alcohols with high product selectivity under visible light irradiation. This reaction process is distinct from that of classic semiconductor photocatalysis.
Co-reporter:Chengyu Mao;Dr. Fan Zuo;Dr. Yang Hou; Xianhui Bu; Pingyun Feng
Angewandte Chemie International Edition 2014 Volume 53( Issue 39) pp:10485-10489
Publication Date(Web):
DOI:10.1002/anie.201406017
Abstract
A new synthetic method to fabricate Ti3+-modified, highly stable TiO2 photoanodes for H2O oxidation is reported. With Ti foil as both the conducting substrate and the Ti3+/Ti4+ source, one-dimensional blue Ti3+/TiO2 crystals were grown by a one-step hydrothermal reaction. The concentration of Ti3+ was further tuned by N2H4 reduction, leading to a greater photoelectrocatalytic activity, as evidenced by a high photocurrent density of 0.64 mA cm−2 at 1.0 V vs RHE under simulated AM 1.5 G illumination. Electron paramagnetic resonance and Mott–Schottky plots reveal that higher charge-carrier density owing to N2H4 reduction contributes to the observed improvement. The generality of this synthesis method was demonstrated by its effectiveness in improving the performance of other types of photoanodes. By integrating the advantages of the 1D TiO2 architecture with those of Ti3+ self-doping, this work provides a versatile tool toward the fabrication of efficient TiO2 photoanodes.
Co-reporter:Dr. Yang Liu;Dr. Qipu Lin; Qichun Zhang; Xianhui Bu; Pingyun Feng
Chemistry - A European Journal 2014 Volume 20( Issue 27) pp:8297-8301
Publication Date(Web):
DOI:10.1002/chem.201402639
Abstract
CdS nanoclusters of four different sizes were integrated with ruthenium-complex dyes. The cluster–dye crystalline composites, [Cd4(SPh)10][Ru(bpy)3], [Cd8S(SPh)16][Ru(bpy)3], [Cd8S(SPh)13⋅Cl⋅(CH3OCS2)2][Ru(phen)3], [Cd17S4(SPh)28][Ru(bpy)3], and [Cd32S14(SPh)40][Ru(phen)3]2 (phen=1,10-phenanthroline and bpy=bipyridine), show intense absorption in the visible-light region. They also exhibit size-dependent photocurrent responses under the illumination of visible light. The photocurrent increases with increased cluster size. The dyes also have significant influence on the photocurrent generation of the composite.
Co-reporter:Tao Wu ; Qian Zhang ; Yang Hou ; Le Wang ; Chengyu Mao ; Shou-Tian Zheng ; Xianhui Bu
Journal of the American Chemical Society 2013 Volume 135(Issue 28) pp:10250-10253
Publication Date(Web):July 2, 2013
DOI:10.1021/ja404181c
We apply a two-step strategy to realize ordered distribution of multiple components in one nanocluster (NC) with a crystallographically ordered core/shell structure. A coreless supertetrahedral chalcogenide Cd-In-S cluster is prepared, and then a copper ion is inserted at its void core site through a diffusion process to form a Cu-Cd-In-S quaternary NC. This intriguing molecular cluster with mono-copper core and Cd-In shell exhibits enhanced visible-light-responsive optical and photoelectric properties compared to the parent NC.
Co-reporter:Jikai Liu, Shuhao Wen, Xiaoxin Zou, Fan Zuo, Gregory J. O. Beran and Pingyun Feng
Journal of Materials Chemistry A 2013 vol. 1(Issue 5) pp:1553-1556
Publication Date(Web):18 Dec 2012
DOI:10.1039/C2TA00522K
Two copper borates, CuB2O4 and Cu3B2O6, produce either H2 or O2 under visible light in the presence of sacrificial agents. Both copper borates exhibit intrinsic midgap states between the valence bands and conduction bands. However, structural differences in the two compounds lead to midgap states with remarkably different photocatalytic behaviors. In CuB2O4, the midgap states facilitate visible light absorption and enhance photocatalytic activity, while in Cu3B2O6 they act as trap states that reduce photocatalytic activity.
Co-reporter:Le Wang, Tao Wu, Xianhui Bu, Xiang Zhao, Fan Zuo, and Pingyun Feng
Inorganic Chemistry 2013 Volume 52(Issue 5) pp:2259-2261
Publication Date(Web):February 20, 2013
DOI:10.1021/ic301965w
Reported here is the first crystalline inorganic–organic hybrid material combining In, Ge, and Cu. The trimetallic system undergoes a nanoscale separation into small In–Ge–S supertetrahedral T2 clusters and large In–Cu–S T5 clusters, which are further assembled into a T2–T5 mixed layer. This material reveals the long-range crystallographically ordered assembly from supertetrahedral clusters with 3 orders of difference, the largest size mismatch known so far for mixed-supertetrahedral-cluster materials. Theoretical simulations were performed to probe the contribution to the band structure by the different-sized semiconducting clusters.
Co-reporter:Qipu Lin, Xianhui Bu, and Pingyun Feng
Crystal Growth & Design 2013 Volume 13(Issue 12) pp:5175-5178
Publication Date(Web):November 14, 2013
DOI:10.1021/cg401579z
The rare coexistence of the copper monomer and paddle-wheel dimer in the same crystal framework creates an apparent linear pseudocopper trimer configuration that induces an unprecedented equalization of pyridyl and carboxyl functionality in a heterofunctional pyridyl dicarboxylate ligand, leading to an intriguing assembly into a highly symmetrical porous framework, despite the low symmetry of the ligand. The material shows a total CO2 uptake of 55 cm3/g at 1 atm and 273 K.
Co-reporter:Dr. Xiaoxin Zou;Jikai Liu;Juan Su;Fan Zuo; Jiesheng Chen; Pingyun Feng
Chemistry - A European Journal 2013 Volume 19( Issue 8) pp:2866-2873
Publication Date(Web):
DOI:10.1002/chem.201202833
Abstract
A novel dopant-free TiO2 photocatalyst (Vo.-TiO2), which is self-modified by a large number of paramagnetic (single-electron-trapped) oxygen vacancies, was prepared by calcining a mixture of a porous amorphous TiO2 precursor, imidazole, and hydrochloric acid at elevated temperature (450 °C) in air. Control experiments demonstrate that the porous TiO2 precursor, imidazole, and hydrochloric acid are all necessary for the formation of Vo.-TiO2. Although the synthesis of Vo.-TiO2 originates from such a multicomponent system, this synthetic approach is facile, controllable, and reproducible. X-ray diffraction, XPS, and EPR spectroscopy reveal that the Vo.-TiO2 material with a high crystallinity embodies a mass of paramagnetic oxygen vacancies, and is free of other dopant species such as nitrogen and carbon. UV/Vis diffuse-reflectance spectroscopy and photoelectrochemical measurement demonstrate that Vo.-TiO2 is a stable visible-light-responsive material with photogenerated charge separation efficiency higher than N-TiO2 and P25 under visible-light irradiation. The Vo.-TiO2 material exhibits not only satisfactory thermal- and photostability, but also superior photocatalytic activity for H2 evolution (115 μmol h−1 g−1) from water with methanol as sacrificial reagent under visible light (λ>400 nm) irradiation. Furthermore, the effects of reaction temperature, ratio of starting materials (imidazole:TiO2 precursor) and calcination time on the photocatalytic activity and the microstructure of Vo.-TiO2 were elucidated.
Co-reporter:Yang Hou;Tao Wu;Le Wang
Science China Chemistry 2013 Volume 56( Issue 4) pp:423-427
Publication Date(Web):2013 April
DOI:10.1007/s11426-013-4847-3
Supertetrahedral zinc-gallium-tin sulfide cluster modified with reduced graphene oxide protective layer was first synthesized, which exhibited an excellent photoelectrochemical performance and enhanced stability in comparison to supertetrahedral clusters.
Co-reporter:Dr. Yang Hou;Dr. Fan Zuo;Alex Dagg ;Dr. Pingyun Feng
Angewandte Chemie 2013 Volume 125( Issue 4) pp:1286-1290
Publication Date(Web):
DOI:10.1002/ange.201207578
Co-reporter:Dr. Yang Hou;Dr. Fan Zuo;Alex Dagg ;Dr. Pingyun Feng
Angewandte Chemie International Edition 2013 Volume 52( Issue 4) pp:1248-1252
Publication Date(Web):
DOI:10.1002/anie.201207578
Co-reporter:Jikai Liu;Dr. Shuhao Wen;Dr. Yang Hou;Dr. Fan Zuo; Gregory J. O. Beran; Pingyun Feng
Angewandte Chemie International Edition 2013 Volume 52( Issue 11) pp:3241-3245
Publication Date(Web):
DOI:10.1002/anie.201209363
Co-reporter:Yang Hou, Fan Zuo, Alex Dagg, and Pingyun Feng
Nano Letters 2012 Volume 12(Issue 12) pp:6464-6473
Publication Date(Web):November 14, 2012
DOI:10.1021/nl303961c
We report the design, synthesis, and characterization of a novel heterojunction array of α-Fe2O3/graphene/BiV1–xMoxO4 core/shell nanorod for photoelectrochemical water splitting. The heterojunction array was prepared by hydrothermal deposition of α-Fe2O3 nanorods onto Ti substrate, with subsequent coating of graphene interlayer and BiV1–xMoxO4 shell by photocatalytic reduction and a spin-coating approach, respectively. The heterojunction yielded a pronounced photocurrent density of ∼1.97 mA/cm2 at 1.0 V vs Ag/AgCl and a high photoconversion efficiency of ∼0.53% at −0.04 V vs Ag/AgCl under the irradiation of a Xe lamp. The improved photoelectrochemical properties benefited from (1) the enhanced light absorption due to behavior of the “window effect” between the α-Fe2O3 cores and BiV1–xMoxO4 shells, and (2) the improved separation of photogenerated carriers at the α-Fe2O3 nanorod/graphene/BiV1–xMoxO4 interfaces. Our results demonstrate the advantages of the novel graphene-mediated core/shell heterojunction array and provide a valuable insight for the further development of such materials.
Co-reporter:Shou-Tian Zheng ; Tao Wu ; Fan Zuo ; Chengtsung Chou ; Pingyun Feng ;Xianhui Bu
Journal of the American Chemical Society 2012 Volume 134(Issue 4) pp:1934-1937
Publication Date(Web):January 19, 2012
DOI:10.1021/ja209800x
A new class of zeolite-type porous materials in which 3D frameworks are covalently functionalized with crystallographically ordered pendant metal clusters have been synthesized. This work demonstrates a new paradigm for and the feasibility of functionalizing zeolite-type frameworks through the conversion of extraframework sites in mineral zeolites into part of the framework for occupation by dangling metal clusters in metal–organic frameworks.
Co-reporter:Tao Wu ; Xianhui Bu ; Puhong Liao ; Le Wang ; Shou-Tian Zheng ; Richard Ma
Journal of the American Chemical Society 2012 Volume 134(Issue 8) pp:3619-3622
Publication Date(Web):February 15, 2012
DOI:10.1021/ja210039u
Supertetrahedral Tn clusters are exact fragments of a cubic ZnS type lattice. Thus far, Tn clusters up to T4 with 20 metal sites can be synthesized in a discrete molecular form. Yet, synthesis of larger discrete supertetrahedral clusters still remains a great challenge, likely due to the rapidly increasing negative charge on the cluster as the size goes up. By using organic superbases (DBN and DBU) to help stabilize the negative charge, a family of discrete supertetrahedral chalcogenide clusters with sizes spanning from T3 (10 metal sites) to T5 (35 metal sites) have been made. The T5 cluster represents the largest molecular supertetrahedral Tn cluster known to date.
Co-reporter:Shou-Tian Zheng ; Tao Wu ; Chengtsung Chou ; Addis Fuhr ; Pingyun Feng ;Xianhui Bu
Journal of the American Chemical Society 2012 Volume 134(Issue 10) pp:4517-4520
Publication Date(Web):February 27, 2012
DOI:10.1021/ja2118255
A general direction for diversifying metal–organic frameworks (MOFs) is demonstrated by the synthesis of composite inorganic clusters between indium and s-, d-, and f-block elements. These previously unknown heterometallic clusters, with various nuclearity, geometry, charge, and metal-to-metal ratios, significantly expand the pool of inorganic building blocks that are highly effective for the construction of porous MOFs with high gas uptake capacity.
Co-reporter:Shou-Tian Zheng ; Chengyu Mao ; Tao Wu ; Sangyune Lee ; Pingyun Feng ;Xianhui Bu
Journal of the American Chemical Society 2012 Volume 134(Issue 29) pp:11936-11939
Publication Date(Web):July 12, 2012
DOI:10.1021/ja305181y
Zeolites are generally made from tetrahedral nodes and ditopic linkers. Reported here is a versatile method based on trifunctional ligands. With this method, two functional groups are used to form zeolitic nets, while the third one serves to immobilize metal clusters within the channels. The process is driven by the coexistence of multiple inorganic building blocks generated in the heterometallic system. The generality of this method is shown by three distinct metal–organic frameworks mimicking AlPO4-5 (AFI) and BCT zeotypes as well as the cubic lcs topology. The correlation between the framework topology and trapped metal species reveals the unique bidirectional control (framework topology ↔ confined metal species) that may be exploited to create a large family of zeotypes with channels modified by different metal ions and clusters.
Co-reporter:Quan-Guo Zhai, Qipu Lin, Tao Wu, Le Wang, Shou-Tian Zheng, Xianhui Bu, and Pingyun Feng
Chemistry of Materials 2012 Volume 24(Issue 14) pp:2624
Publication Date(Web):July 10, 2012
DOI:10.1021/cm301322b
Co-reporter:Le Wang, Jason Morales, Tao Wu, Xiang Zhao, Ward P. Beyermann, Xianhui Bu and Pingyun Feng
Chemical Communications 2012 vol. 48(Issue 60) pp:7498-7500
Publication Date(Web):22 Jun 2012
DOI:10.1039/C2CC32907G
A porous framework comprising a super-supertetrahedral metal–organic cluster building block has been synthesized. Its cubic framework represents a multi-level hierarchical architecture and also possesses an interesting magnetic property.
Co-reporter:Qipu Lin, Tao Wu, Xianhui Bu and Pingyun Feng
Dalton Transactions 2012 vol. 41(Issue 13) pp:3620-3622
Publication Date(Web):23 Feb 2012
DOI:10.1039/C2DT12392D
A twelve-connected 3D metal–organic framework built from a rare linear Cd5(COOR)12 pentamer with selective CO2 uptake, has been prepared and characterized, together with a 2D framework based on a shorter linear Cd3(COOR)6 trimer.
Co-reporter:Xiang Zhao, Tao Wu, Xianhui Bu and Pingyun Feng
Dalton Transactions 2012 vol. 41(Issue 14) pp:3902-3905
Publication Date(Web):02 Dec 2011
DOI:10.1039/C1DT11975C
The use of bifunctional ligands with phenol and pyridyl groups has been found to promote the formation of lithium cubane clusters intrinsically coded with specific preference for various hydrogen-bonding geometries including tetrahedral, square-planar, and linear modes through double, or even quadruple hydrogen bonding between adjacent nodes.
Co-reporter:Quanguo Zhai, Qipu Lin, Tao Wu, Shou-Tian Zheng, Xianhui Bu and Pingyun Feng
Dalton Transactions 2012 vol. 41(Issue 10) pp:2866-2868
Publication Date(Web):17 Jan 2012
DOI:10.1039/C2DT12215D
The use of a desymmetrized tritopic ligand with both carboxyl and pyridyl functionalities leads to the first occurrence of the [Mg3(μ3-OH)(CO2)6] trimer as the 3-D framework building block in a porous crystal that shows relatively high H2 uptake (1.37% at 77 K and 1 atm).
Co-reporter:Fan Zuo;Dr. Krassimir Bozhilov;Robert J. Dillon;Le Wang;Phillip Smith;Xiang Zhao; Christopher Bardeen; Pingyun Feng
Angewandte Chemie International Edition 2012 Volume 51( Issue 25) pp:6223-6226
Publication Date(Web):
DOI:10.1002/anie.201202191
Co-reporter:Yang Hou, Fan Zuo, Quan Ma, Chen Wang, Ludwig Bartels, and Pingyun Feng
The Journal of Physical Chemistry C 2012 Volume 116(Issue 38) pp:20132-20139
Publication Date(Web):September 4, 2012
DOI:10.1021/jp303219j
A graphene-supported Ag3PO4/Ag/AgBr water oxidation photocatalyst was prepared by a photoassisted deposition–precipitation reaction, followed by a hydrothermal treatment. The composite photocatalyst exhibits double the O2-production activity than that of bare Ag3PO4 under visible light irradiation. Moreover, it exhibits enhanced activity in comparison to unsupported Ag3PO4/Ag/AgBr, to graphene-supported bare Ag3PO4 powder as well as to Ag/AgBr powder. This increase in activity is attributed to a combination of depletion of the conduction band of the as-synthesized n-doped Ag3PO4 material and a downshift of the Ag3PO4 valence band due to the pinning of its conduction band at the silver Fermi level, a process that is assisted by charge transfer and distribution onto the graphene support.
Co-reporter:Lei Ge, Fan Zuo, Jikai Liu, Quan Ma, Chen Wang, Dezheng Sun, Ludwig Bartels, and Pingyun Feng
The Journal of Physical Chemistry C 2012 Volume 116(Issue 25) pp:13708-13714
Publication Date(Web):May 29, 2012
DOI:10.1021/jp3041692
Novel CdS quantum dot (QD)-coupled graphitic carbon nitride (g-C3N4) photocatalysts were synthesized via a chemical impregnation method and characterized by X-ray diffraction, transmission electron microscopy, ultraviolet–visible diffuse reflection spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy. The effect of CdS content on the rate of visible light photocatalytic hydrogen evolution was investigated for different CdS loadings using platinum as a cocatalyst in methanol aqueous solutions. The synergistic effect of g-C3N4 and CdS QDs leads to efficient separation of the photogenerated charge carriers and, consequently, enhances the visible light photocatalytic H2 production activity of the materials. The optimal CdS QD content is determined to be 30 wt %, and the corresponding H2 evolution rate was 17.27 μmol·h–1 under visible light irradiation, ∼9 times that of pure g-C3N4. A possible photocatalytic mechanism of the CdS/g-C3N4 composite is proposed and corroborated by photoluminescence spectroscopy and photoelectrochemical curves.
Co-reporter:Fan Zuo;Dr. Krassimir Bozhilov;Robert J. Dillon;Le Wang;Phillip Smith;Xiang Zhao; Christopher Bardeen; Pingyun Feng
Angewandte Chemie 2012 Volume 124( Issue 25) pp:6327-6330
Publication Date(Web):
DOI:10.1002/ange.201202191
Co-reporter:Fei Bu;Dr. Qipu Lin;Dr. Quanguo Zhai;Le Wang;Dr. Tao Wu;Dr. Shou-Tian Zheng;Dr. Xianhui Bu;Dr. Pingyun Feng
Angewandte Chemie International Edition 2012 Volume 51( Issue 34) pp:8538-8541
Publication Date(Web):
DOI:10.1002/anie.201203425
Co-reporter:Tao Wu, Xianhui Bu, Xiang Zhao, Ripsime Khazhakyan, and Pingyun Feng
Journal of the American Chemical Society 2011 Volume 133(Issue 24) pp:9616-9625
Publication Date(Web):May 19, 2011
DOI:10.1021/ja203143q
Doping is among the most important methods to tune the properties of semiconductors. For dense phase semiconductors, the distribution of dopant atoms in crystal lattices is often random. However, when the size of semiconductors becomes increasingly smaller and reaches the extreme situation as is the case in chalcogenide supertetrahedral clusters, different chemically distinct sites (e.g., corner, edge, face, and core) occur, which can dramatically affect the doping chemistry at different sites and also spatial assembly of such clusters into covalent superlattices. In this work, we use the Zn–Ga–Se supertetrahedral clusters and their frameworks as the model system to examine the doping chemistry of Sn4+ and S2– in the Zn–Ga–Se clusters. A series of selenide clusters (undoped supertetrahedral T4-ZnGaSe, S-doped T4-ZnGaSeS, Sn-doped T4-ZnGaSnSe, and dual S- and Sn-doped T4-ZnGaSnSeS) have been prepared with various levels of Sn- and S-doping and with different superlattice structures (OCF-1, -5, -40, and -42). The complex compositional and structural features of these materials are dictated by the convoluted interplay of three key factors: (1) the overall charge density and size/shape matching between clusters/frameworks and protonated guest amines determine the framework topology and the doping levels of Sn4+ and S2–; (2) the site selectivity of Sn4+ is dictated by the local charge balance surrounding anionic Se/S sites as required by the electrostatic valence sum rule; and (3) the site selectivity and doping levels of sulfur is dictated by the location and amount of Sn based on hard soft acid base (HSAB) principle. The cooperative effect of amine-templating and doping by Sn and/or S leads to a rich chemical system with tunable framework compositions, topologies, and electronic properties.
Co-reporter:Zhenyu Zhang ; Qipu Lin ; Dharmalingam Kurunthu ; Tao Wu ; Fan Zuo ; Shou-Tian Zheng ; Christopher J. Bardeen ; Xianhui Bu
Journal of the American Chemical Society 2011 Volume 133(Issue 18) pp:6934-6937
Publication Date(Web):April 18, 2011
DOI:10.1021/ja201670x
The synthesis and photocatalytic properties of a heteropolyoxoniobate, K10[Nb2O2(H2O)2][SiNb12O40]·12H2O (1), are reported, revealing an important role of Zr4+ additives in the crystallization. Compound 1 exhibits overall photocatalytic water splitting activity, and its photocatalytic activity is significantly higher than that of Na10[Nb2O2][SiNb12O40]·xH2O (2). Fluorescence lifetime measurements suggest that the enhanced photocatalytic activity of 1 likely results from a larger yield of longer-lived charge trapping states in 1 due to the coordination of one water molecule to the bridging Nb5+, leading to highly unsymmetrical seven-coordinated Nb5+ sites.
Co-reporter:Tao Wu ; Fan Zuo ; Le Wang ; Xianhui Bu ; Shou-Tian Zheng ; Richard Ma
Journal of the American Chemical Society 2011 Volume 133(Issue 40) pp:15886-15889
Publication Date(Web):September 19, 2011
DOI:10.1021/ja2066994
An entirely new type of chalcogenide cluster and a new structural mechanism for the formation of large semiconducting tetrahedral clusters have been revealed as a result of crystallization of a templated indium sulfide consisting of an unprecedented cluster, In38S65, which is the largest supertetrahedral cluster based on trivalent metal ions. At the core of this cluster is In10S13, which can be considered as a fragment of the NaCl-type lattice. The In10S13 cluster is coupled to four In4S10 supertetrahedral T2 clusters and four In3S3 hexagonal rings to give In38S65, which is also the largest inorganic chalcogenide supertetrahedral cluster, superseding a supertetrahedral T5 cluster with only 35 metal sites.
Co-reporter:Qipu Lin ; Tao Wu ; Shou-Tian Zheng ; Xianhui Bu
Journal of the American Chemical Society 2011 Volume 134(Issue 2) pp:784-787
Publication Date(Web):December 19, 2011
DOI:10.1021/ja2092882
The self-assembly between zinc dimer and 1,3,5-tris(2H-tetrazol-5-yl)benzene (H3BTT), promoted by a urea derivative, leads to a highly porous 3D framework with a large percentage (67%) of N-donor sites unused for bonding with metals. The material exhibits high gas storage capacity (ca. 1.89 wt % H2 at 77 K and 1 atm; 98 cm3/g CO2 at 273 K and 1 atm), even in the absence of open metal sites. The high percentage of open N-donor sites, coupled with the low framework density resulting from single-walled channels, is believed to contribute to the high uptake capacity.
Co-reporter:Zhenyu Zhang, Qipu Lin, Shou-Tian Zheng, Xianhui Bu and Pingyun Feng
Chemical Communications 2011 vol. 47(Issue 13) pp:3918-3920
Publication Date(Web):23 Feb 2011
DOI:10.1039/C0CC04697C
A tin(II) tungstosilicate derivative K11H[Sn4(SiW9O34)2]·25H2O with four sandwiched Sn2+ cations was prepared by reaction of SnCl2, KCl and Na10[α-SiW9O34]·xH2O. Visible-light photocatalytic H2 evolution activity was observed with Pt nanoparticles as co-catalyst and methanol as sacrificial agent.
Co-reporter:Qipu Lin, Tao Wu, Shou-Tian Zheng, Xianhui Bu and Pingyun Feng
Chemical Communications 2011 vol. 47(Issue 43) pp:11852-11854
Publication Date(Web):07 Oct 2011
DOI:10.1039/C1CC14836B
Reported here is a rare example of a highly symmetrical chiral Mg-based MOF (CPF-1) with nanotubular channels, built from 41 (or 43) helical chains. It exhibits a high gas sorption capacity (ca. 1.29 wt% H2 at 77 K, 1 atm; 84 cm3 g−1 of CO2 at 273 K, 1 atm).
Co-reporter:Xiang Zhao, Tao Wu, Shou-Tian Zheng, Le Wang, Xianhui Bu and Pingyun Feng
Chemical Communications 2011 vol. 47(Issue 19) pp:5536-5538
Publication Date(Web):07 Apr 2011
DOI:10.1039/C1CC11245G
Reported here is a lithium cubane based zeolitic framework possessing a multi-dimensional channel system. The unique design strategy of adopting the ditopic ligand 4-pyridinol leads to a rigid porous framework with high thermal stability. It has a BET surface area of 440.3 m2 g−1 and a H2 uptake capacity of 108.7 cm3 g−1 at 77 K.
Co-reporter:Guiyuan Jiang, Tao Wu, Shou-Tian Zheng, Xiang Zhao, Qipu Lin, Xianhui Bu, and Pingyun Feng
Crystal Growth & Design 2011 Volume 11(Issue 9) pp:3713-3716
Publication Date(Web):July 28, 2011
DOI:10.1021/cg200579j
A nine-connected metal–organic framework [NiII2NiIII(μ3-OH)(IN)3(BDC)1.5]·xSolvent (BDC = benzene-1,4-dicarboxylate, IN = isonicotinate) has been prepared and characterized. The application of the scale-down chemistry through the use of the short and inexpensive BDC and IN ligands leads to a smaller pore size and lower surface area but little compromise in H2 sorption properties. The compound exhibits a high CO2 uptake of 73.1 cm3 g–1 (273 K and 1 atm) despite its moderate Langmuir and BET surface areas (888.3 and 571.0 m2 g–1, respectively). Its H2 uptake (1.47 wt % at 77 K and 1 atm) is also quite high, comparable to that of many materials with high surface area.
Co-reporter:Xiang Zhao, Tao Wu, Xianhui Bu and Pingyun Feng
Dalton Transactions 2011 vol. 40(Issue 32) pp:8072-8074
Publication Date(Web):15 Jul 2011
DOI:10.1039/C1DT10859J
Reported here are two 4-connected 3D frameworks based on monomeric lithium nodes, which are synthesized through a mixed ligand route. By combining a negatively charged imidazole ligand and a neutral bis(imidazolyl)methane ligand (or one of its derivatives), neutral frameworks adopting chiral quartz-dual and diamond topologies have been obtained. These materials have low framework density and can reversibly adsorb hydrogen gas.
Co-reporter:Tao Wu;Ripsime Khazhakyan;Le Wang; Xianhui Bu;Dr. Shou-Tian Zheng;Victoria Chau; Pingyun Feng
Angewandte Chemie 2011 Volume 123( Issue 11) pp:2584-2587
Publication Date(Web):
DOI:10.1002/ange.201006531
Co-reporter:Dr. Shou-Tian Zheng;Tao Wu;Burcin Irfanoglu;Fan Zuo;Dr. Pingyun Feng;Dr. Xianhui Bu
Angewandte Chemie 2011 Volume 123( Issue 35) pp:8184-8187
Publication Date(Web):
DOI:10.1002/ange.201103155
Co-reporter:Dr. Shou-Tian Zheng;Jennifer J. Bu;Tao Wu;Chengtsung Chou;Dr. Pingyun Feng;Dr. Xianhui Bu
Angewandte Chemie 2011 Volume 123( Issue 38) pp:9020-9024
Publication Date(Web):
DOI:10.1002/ange.201101957
Co-reporter:Tao Wu;Ripsime Khazhakyan;Le Wang; Xianhui Bu;Dr. Shou-Tian Zheng;Victoria Chau; Pingyun Feng
Angewandte Chemie International Edition 2011 Volume 50( Issue 11) pp:2536-2539
Publication Date(Web):
DOI:10.1002/anie.201006531
Co-reporter:Dr. Shou-Tian Zheng;Tao Wu;Burcin Irfanoglu;Fan Zuo;Dr. Pingyun Feng;Dr. Xianhui Bu
Angewandte Chemie International Edition 2011 Volume 50( Issue 35) pp:8034-8037
Publication Date(Web):
DOI:10.1002/anie.201103155
Co-reporter:Dr. Shou-Tian Zheng;Jennifer J. Bu;Tao Wu;Chengtsung Chou;Dr. Pingyun Feng;Dr. Xianhui Bu
Angewandte Chemie International Edition 2011 Volume 50( Issue 38) pp:8858-8862
Publication Date(Web):
DOI:10.1002/anie.201101957
Co-reporter:Rui Liu, Puhong Liao, Jikai Liu, and Pingyun Feng
Langmuir 2011 Volume 27(Issue 6) pp:3095-3099
Publication Date(Web):February 11, 2011
DOI:10.1021/la104973j
pH-responsive polymer poly(4-vinyl pyridine) is coated on mesoporous silica through the facile “grafting to” method. The grafted polymer nanoshell can work as a pH-sensitive barrier to control the release of trapped molecules from mesoporous silica.
Co-reporter:Le Wang ; Tao Wu ; Fan Zuo ; Xiang Zhao ; Xianhui Bu ; Jianzhong Wu
Journal of the American Chemical Society 2010 Volume 132(Issue 10) pp:3283-3285
Publication Date(Web):February 23, 2010
DOI:10.1021/ja9100672
A Cu−In−S semiconductor consisting of a single piece of a super-supertetrahedron of infinite order has been synthesized through the self-assembly of the largest known Cu−In−S T5 supertetrahedral cluster. One of the most fascinating structural features of this material is its dual hierarchical architecture. Its open-framework architecture can be considered as a “hollowed-out” cubic ZnS-type structure with exactly 64.8% of the total of 1000 atoms in the 5 × 5 × 5 zinc blende supercell removed. The synthetic realization of this material serves to demonstrate a new method for property engineering of semiconducting materials.
Co-reporter:Shou-Tian Zheng ; Julia T. Bu ; Yufei Li ; Tao Wu ; Fan Zuo ; Pingyun Feng ;Xianhui Bu
Journal of the American Chemical Society 2010 Volume 132(Issue 48) pp:17062-17064
Publication Date(Web):November 16, 2010
DOI:10.1021/ja106903p
The integration of negatively charged single-metal building blocks {In(CO2)4} and positively charged trimeric clusters {In3O} leads to three unique cage-within-cage-based porous materials, which exhibit not only high hydrothermal, thermal, and photochemical stability but also attractive structural features contributing to a very high CO2 uptake capacity of up to 119.8 L/L at 273 K and 1 atm.
Co-reporter:Rui Liu ; Ying Zhang ; Xiang Zhao ; Arun Agarwal ; Leonard J. Mueller
Journal of the American Chemical Society 2010 Volume 132(Issue 5) pp:1500-1501
Publication Date(Web):January 19, 2010
DOI:10.1021/ja907838s
A new pH-responsive hybrid nanogated ensemble has been developed by using acetal group linked gold nanoparticle capped mesoporous silica. The hydrolysis of acetal linker at acidic environment makes the gold nanoparticles work as a gatekeeper to control the release of guest molecules from mesoporous silica under different pH’s.
Co-reporter:Tao Wu ; Le Wang ; Xianhui Bu ; Victoria Chau
Journal of the American Chemical Society 2010 Volume 132(Issue 31) pp:10823-10831
Publication Date(Web):July 21, 2010
DOI:10.1021/ja102688p
Supertetrahedral Tn clusters are exact fragments of cubic ZnS-type lattice and are often formed in situ as building units for the construction of 3-D open-framework chalcogenide materials. Small Tn clusters can also be synthesized in discrete forms, allowing them to exist as soluble species in solution. In addition to their tunable electronic and optical properties, these soluble clusters can be used as precursors for the synthesis of porous semiconducting and optical materials. However, the synthesis of large Tn clusters is a significant challenge, and for several decades prior to this work, the size of the discrete Tn cluster remained at T3, with only 10 metal sites (e.g., [Cd10S4(SPh)16]4− and [M5Sn5S20]10−, M = Zn, Co). Here we report a family of discrete chalcogenide T4 clusters ([MxGa18−xSn2Q35]12−, x = 2 or 4; M = Mn, Cu, Zn; Q = S, Se) whose discovery resulted from an unusual phase transformation from a 3-D T4 covalent framework into 0-D T4 molecular clusters. The driving force for such a transformation is the perfect match in both charge density and geometry between chalcogenide clusters and protonated amine, leading to the higher stability of isolated clusters. The perfect match is achieved by using complex quaternary compositions to maximize charge tunability of the cluster. These T4 clusters are the largest molecular Tn clusters known to date and can be made in various compositions showing tunable band structures in both solution and solid state.
Co-reporter:Rui Liu, Puhong Liao, Zhenyu Zhang, Richard J. Hooley, and Pingyun Feng
Chemistry of Materials 2010 Volume 22(Issue 21) pp:5797
Publication Date(Web):October 13, 2010
DOI:10.1021/cm102298y
Co-reporter:Zhenyu Zhang, Fan Zuo and Pingyun Feng
Journal of Materials Chemistry A 2010 vol. 20(Issue 11) pp:2206-2212
Publication Date(Web):02 Feb 2010
DOI:10.1039/B921157H
Mesoporous crystalline anatase TiO2 has been synthesized by using the nanocasting method with mesoporous silica KIT-6 as the hard template and titanium alkoxide as the precursor. Three key synthetic parameters play important roles in the formation of crystalline porous materials. These are precursor/template ratios, calcination temperatures and immersion time (in 2 M NaOH to remove template). The synthesized materials are characterized with powder X-ray diffraction (XRD), N2 adsorption–desorption isotherm analysis and energy-dispersive X-ray spectroscopy (EDX) elemental analysis. Owing to the template confinement effect, mesoporous anatase TiO2 instead of rutile phase was obtained at the calcination temperature of 750 °C. Materials with a surface area as high as 207 m2 g−1 have been obtained. The photocatalytic activities of the as-prepared mesoporous TiO2 were studied with a loading of 0.5% Pt. The materials with higher surface areas showed higher H2 evolution activities. The H2 evolution activity of the mesoporous anatase sample prepared under optimal conditions was 5.5 times higher than that of bulk anatase TiO2. The work represents a step forward in the development of highly efficient photocatalysts based on crystalline high surface area porous materials and our results indicate that the hard template method may be an effective method to achieve this goal.
Co-reporter:Dr. Shou-Tian Zheng;Yufei Li;Tao Wu;Ruben A. Nieto;Dr. Pingyun Feng;Dr. Xianhui Bu
Chemistry - A European Journal 2010 Volume 16( Issue 44) pp:13035-13040
Publication Date(Web):
DOI:10.1002/chem.201002316
Co-reporter:Shoutian Zheng Dr.;Tao Wu;Jian Zhang Dr.;Mina Chow;RubenA. Nieto Dr.;Xianhui Bu Dr.
Angewandte Chemie 2010 Volume 122( Issue 31) pp:5490-5494
Publication Date(Web):
DOI:10.1002/ange.201001675
Co-reporter:Dr. Shou-Tian Zheng;Yufei Li;Tao Wu;Ruben A. Nieto;Dr. Pingyun Feng;Dr. Xianhui Bu
Chemistry - A European Journal 2010 Volume 16( Issue 44) pp:
Publication Date(Web):
DOI:10.1002/chem.201090218
Co-reporter:Shoutian Zheng Dr.;Tao Wu;Jian Zhang Dr.;Mina Chow;RubenA. Nieto Dr.;Xianhui Bu Dr.
Angewandte Chemie International Edition 2010 Volume 49( Issue 31) pp:5362-5366
Publication Date(Web):
DOI:10.1002/anie.201001675
Co-reporter:Rui Liu ; Ying Zhang
Journal of the American Chemical Society 2009 Volume 131(Issue 42) pp:15128-15129
Publication Date(Web):September 11, 2009
DOI:10.1021/ja905288m
A new multiresponsive supramolecular nanogated ensemble has been developed by introducing β-cyclodextrin (β-CD) into polymer-grafted mesoporous silica. The cross-linked polymer produced by host−guest interaction between β-CD and diazo-linker works as a gatekeeper to control the release of trapped molecules from hybrid materials. The presence of UV light, α-CD, or disulfide reducing agent can effectively open the polymeric network and release the loading with different dynamics.
Co-reporter:Shumei Chen ; Jian Zhang ; Tao Wu ; Pingyun Feng ;Xianhui Bu
Journal of the American Chemical Society 2009 Volume 131(Issue 44) pp:16027-16029
Publication Date(Web):October 20, 2009
DOI:10.1021/ja906302t
Under diverse and dramatically different chemical environments, including organic solvents, an ionic liquid, and a deep eutectic solvent, a series of porous anionic framework materials that contain size-tunable, ion-exchangeable extraframework organic cations have been prepared. Even though a large fraction of the pore space is occupied with charge-balancing cations, some of these materials exhibit a very high gas uptake capacity (e.g., 70.6 cm3/g for CO2 at 1 atm and 273 K), suggesting that the charged anionic framework and extraframework cations may help to enhance the gas adsorption.
Co-reporter:Tao Wu, Jian Zhang, Xianhui Bu and Pingyun Feng
Chemistry of Materials 2009 Volume 21(Issue 16) pp:3830
Publication Date(Web):August 3, 2009
DOI:10.1021/cm9015063
Despite years of efforts, known metal−organic frameworks rely predominantly on the use of group 12, d- and f-block elements. Recently, there has been a surge of interest in the use of s- and p-block elements (e.g., Mg and Al) as framework polyhedral nodes. Still, there are much fewer framework materials constructed from lightweight second-row elements (e.g., Li and B). Here we report three framework structures constructed by using lithium and boron as 3- or 4-connected nodes. It is shown that structural features of the poly(azolyl)borate anion can be used to induce 3-connected lithium sites, as compared to much more common 4-connected lithium sites. The creation of 3-connected lithium is of significance because it may offer open metal sites for enhanced guest binding. BIF-10 is a 3-connected three-dimensional lithium boron imidazolate built from the tripodal [BH(mim)3]− anion (mim = 2-methylimidazolyl). One unique feature of BIF-10 is that lithium sites in two interpenetrating sublattices have different coordination numbers (tetrahedral with a terminating DMF molecule or trigonal planar). BIF-11 built from the tetrahedral [B(2,4-dmim)4]− anion (2,4-dmim = 2,4-dimethylimidazolyl) possesses the sodalite-type framework and represents an ideal example that demonstrates the competitive structure-directing effect of two methyl substituents. BIF-12 built from tetrahedral [B(bim)4]− anion (bim = benzimidazolyl) has a 3-connected layer structure with a dangling bim group, revealing another way in which the structure of poly(azolyl)borate anions can induce the 3-connected lithium site.
Co-reporter:Tao Wu;Xiqing Wang;Xianhui Bu Dr.;Xiang Zhao;Le Wang Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 39) pp:7204-7207
Publication Date(Web):
DOI:10.1002/anie.200903758
Co-reporter:Tao Wu;Xiqing Wang;Xianhui Bu Dr.;Xiang Zhao;Le Wang Dr.
Angewandte Chemie 2009 Volume 121( Issue 39) pp:7340-7343
Publication Date(Web):
DOI:10.1002/ange.200903758
Co-reporter:Jian Zhang Dr.;Tao Wu;Cong Zhou;Shumei Chen Dr. Dr.;Xianhui Bu Dr.
Angewandte Chemie 2009 Volume 121( Issue 14) pp:2580-2583
Publication Date(Web):
DOI:10.1002/ange.200804169
Co-reporter:Jian Zhang Dr.;Tao Wu;Cong Zhou;Shumei Chen Dr. Dr.;Xianhui Bu Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 14) pp:2542-2545
Publication Date(Web):
DOI:10.1002/anie.200804169
Co-reporter:Qichun Zhang, Tao Wu, Xianhui Bu, Tri Tran and Pingyun Feng
Chemistry of Materials 2008 Volume 20(Issue 13) pp:4170
Publication Date(Web):June 17, 2008
DOI:10.1021/cm800904d
Co-reporter:Qichun Zhang, Zhien Lin, Xianhui Bu, Tao Wu and Pingyun Feng
Chemistry of Materials 2008 Volume 20(Issue 10) pp:3239
Publication Date(Web):April 30, 2008
DOI:10.1021/cm702874s
Co-reporter:Tao Wu, Xianhui Bu, Jian Zhang and Pingyun Feng
Chemistry of Materials 2008 Volume 20(Issue 24) pp:7377
Publication Date(Web):December 3, 2008
DOI:10.1021/cm802400f
Five 4-connected zeolitic metal imidazolate frameworks have been synthesized by using complementary ligands in combination with fine-tuning of synthetic parameters such as solvent ratio. These materials exhibit four different tetrahedral topologies. In TIF-2 and TIF-3, the cubic double 4-ring units are assembled into two different topologies not previously found in metal imidazolates. TIF-2 possesses one-dimensional 12-ring channels and an unprecedented 4-connected topology. It exhibits permanent microporosity and high thermal stability. TIF-3 is the first known example of metal imidazolates with the zeolitic ACO topology. In TIF-4, TIF-5Zn, and TIF-5Co, two complementary ligands (one small and one large) control the framework topology in a cooperative manner with small ligands favoring small rings (such as 4-rings) and large ligands favoring large rings such as 6- and 8-rings, which highlights the significance of framework building units (i.e., cross-linking ligands) in the control of the framework topology, in distinct contrast with inorganic framework materials (e.g., zeolites) in which the framework topology is primarily controlled by extra-framework structure-directing agents. These new frameworks underline the rich synthetic and structural chemistry of metal-imidazolate-based porous frameworks.
Co-reporter:Qichun Zhang ; Xianhui Bu ; Zhien Lin ; Tao Wu
Inorganic Chemistry 2008 Volume 47(Issue 21) pp:9724-9726
Publication Date(Web):October 2, 2008
DOI:10.1021/ic800588q
Using predesigned tetrahedral quadridentate linker tetrakis(4-pyridyloxymethylene)methane (TPOM) as the organic linker, tetrahedral P1 clusters ([Cd8S(SPh)16]2−) and C1 clusters ([Cd17S4(SPh)28]2−) have been assembled into beltlike (MCOF-9) or chainlike (MCOF-10) configurations, as determined by single-crystal X-ray diffraction. The onset of optical absorptions of MCOF-9 and MCOF-10 is around 400 and 420 nm, respectively. The thermal analysis shows that both materials are stable up to 250 °C.
Co-reporter:Tao Wu;Xianhui Bu Dr.;Rui Liu;Zhien Lin Dr.;Jian Zhang Dr. Dr.
Chemistry - A European Journal 2008 Volume 14( Issue 26) pp:7771-7773
Publication Date(Web):
DOI:10.1002/chem.200800736
Co-reporter:Zhenyu Zhang Dr.;Quan Cheng Dr. Dr.
Angewandte Chemie International Edition 2008 Volume 48( Issue 1) pp:118-122
Publication Date(Web):
DOI:10.1002/anie.200803840
Co-reporter:Zhenyu Zhang Dr.;Quan Cheng Dr. Dr.
Angewandte Chemie 2008 Volume 121( Issue 1) pp:124-128
Publication Date(Web):
DOI:10.1002/ange.200803840
Co-reporter:Nanfeng Zheng, Jian Zhang, Xianhui Bu and Pingyun Feng
Crystal Growth & Design 2007 Volume 7(Issue 12) pp:2576
Publication Date(Web):November 3, 2007
DOI:10.1021/cg0705456
Functionalized tetraarylporphyrin molecules have been widely used as ligands for the design of supramolecular coordination arrays. Even though a large number of porphyrin coordination compounds have been synthesized, three-dimensional networks are still less common. Here we report the hydrothermal synthesis and structure characterizations of four cadmium−porphyrin compounds based on meso-tetra(4-pyridyl)porphyrin (H2TPyP). In these structures, both cadmium and porphyrin exhibit rich coordination chemistry. The porphyrin molecule displays four types of coordination modes in which each porphyrin molecule bonds to one, two, four, and five cadmium sites. The Cd2+ site shows equally diverse coordination modes and exists in five different coordination environments. The porphyrin molecules are connected through Cd2+ cations or Cd3(SC2H2OH)24+ clusters into molecular (Cd−TPyP-1), two-dimensional (Cd−TPyP-4), and three-dimensional networks (Cd−H2TPyP-2 and Cd−TPyP-3). Three-dimensional frameworks are of particular interest because they adopt interesting and rare framework topologies (cds and hms types).
Co-reporter:Qichun Zhang;Yang Liu Dr.;Xianhui Bu Dr.;Tao Wu Dr.
Angewandte Chemie International Edition 2007 Volume 47( Issue 1) pp:113-116
Publication Date(Web):
DOI:10.1002/anie.200703442
Co-reporter:Qichun Zhang;Yang Liu Dr.;Xianhui Bu Dr.;Tao Wu Dr.
Angewandte Chemie 2007 Volume 120( Issue 1) pp:119-122
Publication Date(Web):
DOI:10.1002/ange.200703442
Co-reporter:Jingli Xie, Xianhui Bu, Nanfeng Zheng and Pingyun Feng
Chemical Communications 2005 (Issue 39) pp:4916-4918
Publication Date(Web):13 Sep 2005
DOI:10.1039/B508470A
Three new one-dimensional coordination polymers [Zn8S(SC6H5)14·C12H10N2](1), [Zn7CoS(SC6H5)14·C13H14N2](2) and [Zn8S(SC6H5)14·C13H14N2](3) have been prepared containing penta-supertetrahedral clusters and linear crosslinking dipyridyl ligands; the two complexes show optical transitions with band gaps of ∼3.44 eV (1) and ∼3.54 eV (2).
Co-reporter:Nanfeng Zheng, Xianhui Bu and Pingyun Feng
Chemical Communications 2005 (Issue 22) pp:2805-2807
Publication Date(Web):22 Apr 2005
DOI:10.1039/B501775K
Under the structure-directing effect of a metal complex formed in situ, supertetrahedral [ZnGe3S6(H2O)(S3)1/2]1− clusters alternate with tetrahedral Zn(H2O)(S3)1/21− units to form a two-dimensional wide bandgap semiconductor that shows photocatalytic activity for H2 production from aqueous solution.
Co-reporter:Nanfeng Zheng;Xianhui Bu ;Hiep Vu
Angewandte Chemie International Edition 2005 Volume 44(Issue 33) pp:
Publication Date(Web):22 JUL 2005
DOI:10.1002/anie.200500346
Light work: Open-framework chalcogenides are efficient visible-light photocatalysts for the reduction of water to hydrogen. These materials contain 3D covalent superlattices built from nanosized supertetrahedral clusters (see picture). Unlike dense semiconductors, they allow the easy incorporation of dye sensitizers within their channels, which can further enhance their photocatalytic response in the visible-light region.
Co-reporter:Xianhui Bu ;Nanfeng Zheng;Xiqing Wang;Bing Wang
Angewandte Chemie 2004 Volume 116(Issue 12) pp:
Publication Date(Web):9 MAR 2004
DOI:10.1002/ange.200352880
Feuchteabhängige elektrische Leitfähigkeit, mit Anwendungspotenzial in der Sensortechnik, liegt bei OCF-6GaSe vor, einem aus T3 (Ga10Se2010−) zusammengesetzten supratetraedrischen Galliumselenid mit offener Gerüststruktur (siehe Bild, links). Weiterhin wurden Materialien auf der Basis von T4 (Zn4Ga16Se3514−, rechts) erhalten, dem größten bislang bekannten supratetraedrischen Selenid-Cluster.
Co-reporter:Xianhui Bu ;Nanfeng Zheng
Chemistry - A European Journal 2004 Volume 10(Issue 14) pp:
Publication Date(Web):18 MAY 2004
DOI:10.1002/chem.200306041
By integrating porosity with electrical or optical properties, microporous chalcogenides may have unique applications. Here we review recent advances and discuss concepts in the synthesis and crystal structure of tetrahedral clusters and their frameworks. These chalcogenides can be viewed as trivalent metal chalcogenides doped with tetra-, di-, or monovalent metal cations. Low-valent cations help to increase the cluster size, while high-valent cations have the opposite effect.
Co-reporter:Nanfeng Zheng;Xianhui Bu
Angewandte Chemie 2004 Volume 116(Issue 36) pp:
Publication Date(Web):7 SEP 2004
DOI:10.1002/ange.200460386
Bewegliche Kationen in einem offenen 3D-Gerüst bedingen die hohe Ionenleitfähigkeit von ICF-26. Das Netz besteht aus Li4In22S4418−-Clustern, dem zweiten Glied einer Reihe von Pentasupertetraeder-Clustern Pn. Der beschriebene P2-Cluster ist der bisher größte bekannte Vertreter dieser Pn-Reihe. Im Kristall sind die P2-Cluster über alle vier Ecken mit benachbarten P2-Clustern verknüpft (siehe Bild).
Co-reporter:Xianhui Bu ;Nanfeng Zheng
Chemistry - A European Journal 2004 Volume 10(Issue 14) pp:
Publication Date(Web):8 JUL 2004
DOI:10.1002/chem.200490046
Co-reporter:Xianhui Bu ;Nanfeng Zheng;Xiqing Wang;Bing Wang
Angewandte Chemie International Edition 2004 Volume 43(Issue 12) pp:
Publication Date(Web):9 MAR 2004
DOI:10.1002/anie.200352880
Humidity-dependent electrical conductivity, which suggests possible applications in sensors, is exhibited by OCF-6GaSe, an open-framework gallium selenide assembled from T3 (Ga10Se2010−) supertetrahedral clusters (picture, left). Furthermore, materials based on T4 (Zn4Ga16Se3514−, right), the largest supertetrahedral selenide cluster so far, were also obtained.
Co-reporter:Nanfeng Zheng;Xianhui Bu
Angewandte Chemie International Edition 2004 Volume 43(Issue 36) pp:
Publication Date(Web):7 SEP 2004
DOI:10.1002/anie.200460386
Highly mobile extra-framework cations encapsulated in the 3D open-framework architecture of ICF-26 result in remarkably high ion conductivity. The framework is composed of Li4In22S4418− clusters, which represent the second member of a series of pentasupertetrahedral clusters Pn. The P2 cluster reported here is the largest member of the Pn series so far. In the crystal, each P2 cluster shares all four corners with adjacent P2 clusters (see picture).
Co-reporter:Nanfeng Zheng,
Xianhui Bu
and
Pingyun Feng
Nature 2003 426(6965) pp:428
Publication Date(Web):
DOI:10.1038/nature02159
Co-reporter:Cheng Wang, Xianhui Bu, Nanfeng Zheng and Pingyun Feng
Chemical Communications 2002 (Issue 13) pp:1344-1345
Publication Date(Web):22 May 2002
DOI:10.1039/B203253H
Three-dimensional open framework selenides and tellurides are rare despite the recent progress in the synthesis of indium sulfides with large pore sizes; here we report a family of amine-directed indium selenide superlattices constructed from T3 supertetrahedral (In10Se18)6− clusters.
Co-reporter:Cheng Wang Dr.;Xianhui Bu Dr.;Nanfeng Zheng
Angewandte Chemie International Edition 2002 Volume 41(Issue 11) pp:
Publication Date(Web):28 MAY 2002
DOI:10.1002/1521-3773(20020603)41:11<1959::AID-ANIE1959>3.0.CO;2-I
Fine-tuning structures: A family of noncluster-based 3D open-framework indium chalcogenides are reported. The framework composition is highly flexible and controllable. Such a compositional diversity makes it feasible to tune structural, electronic, and optical properties. The structure shows a polyhedral view of 3D cross-linking in an In–Te compound.
Co-reporter:Cheng Wang Dr.;Xianhui Bu Dr.;Nanfeng Zheng
Angewandte Chemie 2002 Volume 114(Issue 11) pp:
Publication Date(Web):28 MAY 2002
DOI:10.1002/1521-3757(20020603)114:11<2039::AID-ANGE2039>3.0.CO;2-6
Fein abstimmbare Eigenschaften: Eine Familie dreidimensionaler Gerüst-Indiumchalkogenide wird vorgestellt, die nicht auf Clustern basiert. Die Zusammensetzung des Gerüsts ist hoch flexibel und kontrollierbar. Solch eine Vielfalt bei der Zusammensetzung ermöglicht die Abstimmung struktureller, elektronischer und optischer Eigenschaften. Das Bild zeigt eine dreidimensionale Vernetzung in einer In-Te-Verbindung.
Co-reporter:Fan Zuo ; Le Wang ; Tao Wu ; Zhenyu Zhang ; Dan Borchardt
Journal of the American Chemical Society () pp:
Publication Date(Web):August 5, 2010
DOI:10.1021/ja103843d
Through a facile one-step combustion method, partially reduced TiO2 has been synthesized. Electron paramagnetic resonance (EPR) spectra confirm the presence of Ti3+ in the bulk of an as-prepared sample. The UV−vis spectra show that the Ti3+ here extends the photoresponse of TiO2 from the UV to the visible light region, which leads to high visible-light photocatalytic activity for the generation of hydrogen gas from water. It is worth noting that the Ti3+ sites in the sample are highly stable in air or water under irradiation and the photocatalyst can be repeatedly used without degradation in the activity.
Co-reporter:Jian Guo, Chengyu Mao, Ruikang Zhang, Mingfei Shao, Min Wei and Pingyun Feng
Journal of Materials Chemistry A 2017 - vol. 5(Issue 22) pp:NaN11025-11025
Publication Date(Web):2017/05/02
DOI:10.1039/C7TA00770A
Photoelectrochemical (PEC) water oxidation has received considerable attention owing to its key role in the overall water splitting. In this work, several reduced titania@layered double hydroxide (CoAl–LDH, CoCr–LDH, and CoFe–LDH) hybrid photoanodes were fabricated via electrochemical deposition of LDH on the reduced titania, and their PEC properties for water oxidation were studied systematically. The reduced titania@CoCr–LDH photoanode shows a much improved PEC performance compared with pristine reduced titania, with a photocurrent density enhancement of 43% (from 0.65 mA cm−2 to 0.93 mA cm−2) and an onset potential decrease of 21% (from 0.23 V to 0.18 V vs. the RHE). This improvement is also successfully demonstrated in the reduced titania@CoAl–LDH and reduced titania@CoFe–LDH system. The photoconversion efficiency of reduced titania is significantly enhanced after the incorporation of LDH (0.42–0.51% at ∼0.46 V vs. the RHE). Both the experimental studies and DFT calculations confirm a synergistic effect between the reduced titania and LDH. The results show that a good match of the band structure facilitates the fast electron–hole separation and the migration of holes from reduced titania to LDH, followed by the LDH catalyzed water oxidation. The CoCr–LDH has the highest driving force for oxygen evolution among these LDHs, accounting for the optimal PEC performance of the reduced titania@CoCr–LDH photoanode.
Co-reporter:Xiang Zhao, Tao Wu, Xianhui Bu and Pingyun Feng
Dalton Transactions 2011 - vol. 40(Issue 32) pp:NaN8074-8074
Publication Date(Web):2011/07/15
DOI:10.1039/C1DT10859J
Reported here are two 4-connected 3D frameworks based on monomeric lithium nodes, which are synthesized through a mixed ligand route. By combining a negatively charged imidazole ligand and a neutral bis(imidazolyl)methane ligand (or one of its derivatives), neutral frameworks adopting chiral quartz-dual and diamond topologies have been obtained. These materials have low framework density and can reversibly adsorb hydrogen gas.
Co-reporter:Xiang Zhao, Tao Wu, Xianhui Bu and Pingyun Feng
Dalton Transactions 2012 - vol. 41(Issue 14) pp:NaN3905-3905
Publication Date(Web):2011/12/02
DOI:10.1039/C1DT11975C
The use of bifunctional ligands with phenol and pyridyl groups has been found to promote the formation of lithium cubane clusters intrinsically coded with specific preference for various hydrogen-bonding geometries including tetrahedral, square-planar, and linear modes through double, or even quadruple hydrogen bonding between adjacent nodes.
Co-reporter:Zhenyu Zhang, Qipu Lin, Shou-Tian Zheng, Xianhui Bu and Pingyun Feng
Chemical Communications 2011 - vol. 47(Issue 13) pp:NaN3920-3920
Publication Date(Web):2011/02/23
DOI:10.1039/C0CC04697C
A tin(II) tungstosilicate derivative K11H[Sn4(SiW9O34)2]·25H2O with four sandwiched Sn2+ cations was prepared by reaction of SnCl2, KCl and Na10[α-SiW9O34]·xH2O. Visible-light photocatalytic H2 evolution activity was observed with Pt nanoparticles as co-catalyst and methanol as sacrificial agent.
Co-reporter:Zhenyu Zhang, Fan Zuo and Pingyun Feng
Journal of Materials Chemistry A 2010 - vol. 20(Issue 11) pp:NaN2212-2212
Publication Date(Web):2010/02/02
DOI:10.1039/B921157H
Mesoporous crystalline anatase TiO2 has been synthesized by using the nanocasting method with mesoporous silica KIT-6 as the hard template and titanium alkoxide as the precursor. Three key synthetic parameters play important roles in the formation of crystalline porous materials. These are precursor/template ratios, calcination temperatures and immersion time (in 2 M NaOH to remove template). The synthesized materials are characterized with powder X-ray diffraction (XRD), N2 adsorption–desorption isotherm analysis and energy-dispersive X-ray spectroscopy (EDX) elemental analysis. Owing to the template confinement effect, mesoporous anatase TiO2 instead of rutile phase was obtained at the calcination temperature of 750 °C. Materials with a surface area as high as 207 m2 g−1 have been obtained. The photocatalytic activities of the as-prepared mesoporous TiO2 were studied with a loading of 0.5% Pt. The materials with higher surface areas showed higher H2 evolution activities. The H2 evolution activity of the mesoporous anatase sample prepared under optimal conditions was 5.5 times higher than that of bulk anatase TiO2. The work represents a step forward in the development of highly efficient photocatalysts based on crystalline high surface area porous materials and our results indicate that the hard template method may be an effective method to achieve this goal.
Co-reporter:Qipu Lin, Xianhui Bu and Pingyun Feng
Chemical Communications 2014 - vol. 50(Issue 31) pp:NaN4046-4046
Publication Date(Web):2014/02/27
DOI:10.1039/C4CC00583J
A new super-supertetrahedral cluster, resembling a coreless supertetrahedral T6 cluster, was made as a tin oxyselenide by integrating hard and soft Lewis bases (O2− and Se2−) into the tetravalent system. Its hierarchical architecture, built from supertetrahedral T3-[Sn10O4Se20] and Sn2Se6 clusters, represents a new level of complexity in the cluster-based construction. Compared to pure tin selenides, the new tin oxyselenide material in this work shows much enhanced stability and size-dependent band energy level.
Co-reporter:Jikai Liu, Shuhao Wen, Xiaoxin Zou, Fan Zuo, Gregory J. O. Beran and Pingyun Feng
Journal of Materials Chemistry A 2013 - vol. 1(Issue 5) pp:NaN1556-1556
Publication Date(Web):2012/12/18
DOI:10.1039/C2TA00522K
Two copper borates, CuB2O4 and Cu3B2O6, produce either H2 or O2 under visible light in the presence of sacrificial agents. Both copper borates exhibit intrinsic midgap states between the valence bands and conduction bands. However, structural differences in the two compounds lead to midgap states with remarkably different photocatalytic behaviors. In CuB2O4, the midgap states facilitate visible light absorption and enhance photocatalytic activity, while in Cu3B2O6 they act as trap states that reduce photocatalytic activity.
Co-reporter:Le Wang, Jason Morales, Tao Wu, Xiang Zhao, Ward P. Beyermann, Xianhui Bu and Pingyun Feng
Chemical Communications 2012 - vol. 48(Issue 60) pp:NaN7500-7500
Publication Date(Web):2012/06/22
DOI:10.1039/C2CC32907G
A porous framework comprising a super-supertetrahedral metal–organic cluster building block has been synthesized. Its cubic framework represents a multi-level hierarchical architecture and also possesses an interesting magnetic property.
Co-reporter:Xiang Zhao, Tao Wu, Shou-Tian Zheng, Le Wang, Xianhui Bu and Pingyun Feng
Chemical Communications 2011 - vol. 47(Issue 19) pp:NaN5538-5538
Publication Date(Web):2011/04/07
DOI:10.1039/C1CC11245G
Reported here is a lithium cubane based zeolitic framework possessing a multi-dimensional channel system. The unique design strategy of adopting the ditopic ligand 4-pyridinol leads to a rigid porous framework with high thermal stability. It has a BET surface area of 440.3 m2 g−1 and a H2 uptake capacity of 108.7 cm3 g−1 at 77 K.
Co-reporter:Qipu Lin, Tao Wu, Xianhui Bu and Pingyun Feng
Dalton Transactions 2012 - vol. 41(Issue 13) pp:NaN3622-3622
Publication Date(Web):2012/02/23
DOI:10.1039/C2DT12392D
A twelve-connected 3D metal–organic framework built from a rare linear Cd5(COOR)12 pentamer with selective CO2 uptake, has been prepared and characterized, together with a 2D framework based on a shorter linear Cd3(COOR)6 trimer.
Co-reporter:Aiguo Kong, Chengyu Mao, Qipu Lin, Xiao Wei, Xianhui Bu and Pingyun Feng
Dalton Transactions 2015 - vol. 44(Issue 15) pp:NaN6754-6754
Publication Date(Web):2015/01/26
DOI:10.1039/C4DT03726J
By one-step pyrolysis of a unique “cage-in-cage” cobalt metal–organic framework, nitrogen-doped carbon cubes embedded with numerous metallic Co nanoparticles were obtained. A considerable amount of Co particles was encapsulated in thin carbon shells and formed the core–shell-like Co@C structure. With about 60 wt% Co particles in the prepared sample, the nanocomposites of Co nanoparticles and nitrogen-doped carbon show electrocatalytic activity for the oxygen reduction reaction (ORR) with an efficiency comparable to the commercial Pt/C catalyst, but with better durability and methanol-tolerance performance. The metallic Co nanoparticles were found to play an important role in enhancing the ORR activity of the nanocomposites. This simple one-step pyrolysis method provides a novel synthetic route for the synthesis of core–shell-like Co@C nano-composites. The synthesized material represents a highly active non-precious metal catalyst for ORR.
Co-reporter:Fei Bu, Qipu Lin, Quan-Guo Zhai, Xianhui Bu and Pingyun Feng
Dalton Transactions 2015 - vol. 44(Issue 38) pp:NaN16674-16674
Publication Date(Web):2015/08/20
DOI:10.1039/C5DT02861B
By using the same ligand, 2,5-furandicarboxylic acid (FDA), and varying synthetic conditions (especially the In3+/FDA ratio), it is possible to access three unique building blocks of indium, demonstrating charge-switching from a positive trimer to a negative monomer and leading to the synthesis of In-MOFs with tunable framework charge.
Co-reporter:Quanguo Zhai, Qipu Lin, Tao Wu, Shou-Tian Zheng, Xianhui Bu and Pingyun Feng
Dalton Transactions 2012 - vol. 41(Issue 10) pp:NaN2868-2868
Publication Date(Web):2012/01/17
DOI:10.1039/C2DT12215D
The use of a desymmetrized tritopic ligand with both carboxyl and pyridyl functionalities leads to the first occurrence of the [Mg3(μ3-OH)(CO2)6] trimer as the 3-D framework building block in a porous crystal that shows relatively high H2 uptake (1.37% at 77 K and 1 atm).
Co-reporter:Koroush Sasan, Qipu Lin, ChengYu Mao and Pingyun Feng
Chemical Communications 2014 - vol. 50(Issue 72) pp:NaN10393-10393
Publication Date(Web):2014/07/25
DOI:10.1039/C4CC03946G
A new biomimetic heterogeneous photocatalyst ([FeFe]@ZrPF) has been synthesized through the incorporation of homogeneous complex 1 [(í-SCH2)2NC(O)C5H4N]–[Fe2(CO)6] into the highly robust zirconium-porphyrin based metal–organic framework (ZrPF). The immobilized biomimetic [Fe2S2] catalyst inside the MOF shows great improvement in hydrogen generation compared to the reference homogeneous catalyst complex 1.
Co-reporter:Aiguo Kong, Qipu Lin, Chengyu Mao, Xianhui Bu and Pingyun Feng
Chemical Communications 2014 - vol. 50(Issue 98) pp:NaN15622-15622
Publication Date(Web):2014/10/31
DOI:10.1039/C4CC06867J
By one-step pyrolysis of an indium–MOF with entrapped cobalt dimers in the presence of melamine, heterometallic carbide nanoparticles (Co3InC0.75) embedded in nitrogen-enriched carbon have been prepared and found to exhibit efficient electrocatalytic activity for oxygen reduction reaction with high durability and methanol-tolerance properties.
Co-reporter:Qipu Lin, Tao Wu, Shou-Tian Zheng, Xianhui Bu and Pingyun Feng
Chemical Communications 2011 - vol. 47(Issue 43) pp:NaN11854-11854
Publication Date(Web):2011/10/07
DOI:10.1039/C1CC14836B
Reported here is a rare example of a highly symmetrical chiral Mg-based MOF (CPF-1) with nanotubular channels, built from 41 (or 43) helical chains. It exhibits a high gas sorption capacity (ca. 1.29 wt% H2 at 77 K, 1 atm; 84 cm3 g−1 of CO2 at 273 K, 1 atm).
![[1,1'-Biphenyl]-4-carboxylic acid, 4',4''',4''''',4'''''''-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis-](/data/chemimg/3718100/609365-68-6.png)
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![21H,23H-Porphine, 5,10,15,20-tetrakis[4-[2-(trimethylsilyl)ethynyl]phenyl]-](/data/chemimg/2944500/145362-97-6_b.png)
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