Co-reporter:Jinhui Zhu;Jun Yang;Zhixin Xu;Jiulin Wang;Yanna Nuli;Xinliang Feng
Nanoscale (2009-Present) 2017 vol. 9(Issue 25) pp:8871-8878
Publication Date(Web):2017/06/29
DOI:10.1039/C7NR01545C
Silicon (Si) anodes, which are among the most promising candidates for high-energy lithium-ion batteries (LIBs), have attracted considerable attention from both academic and industrial communities. However, Si anodes usually suffer from an inherently low conductivity and extremely large volume change during the lithiation and delithiation processes, and consequently exhibit an inferior rate capability and poor cycle life. In this paper, we report new porous polymer-derived carbon coated Si nanoparticles (NPs) as the next generation anodes for LIBs to overcome these serious problems. Specifically, a porous covalent triazine framework (CTF) polymer shell was synthesized by in situ trimerization of p-benzenedinitrile in molten ZnCl2. Then, core–shell structured Si/nitrogen-doped porous carbon (Si@NPC) spheres were easily produced after high-temperature annealing. As an anode for LIBs, Si@NPC delivers a high capacity of 1390 mA h g−1 at 0.5 A g−1, stable cycle performance (107% capacity retention at 1 A g−1 for 200 cycles), and excellent rate capability of up to approximately 420 mA h g−1 at 16 A g−1. Such an exciting performance can be attributed to the ultra-stable, highly conductive, N-doped, and porous carbon shell. This work not only offers a new solution to the large volume change of Si-based anodes, but also enables the synthesis of porous polymer-based core–shell structures for energy storage and conversion.
Co-reporter:Shuai Bi;Zhi-An Lan;Silvia Paasch;Wenbei Zhang;Yafei He;Chao Zhang;Feng Liu;Dongqing Wu;Eike Brunner;Xinchen Wang;Fan Zhang
Advanced Functional Materials 2017 Volume 27(Issue 39) pp:
Publication Date(Web):2017/10/01
DOI:10.1002/adfm.201703146
AbstractPolymeric semiconductors are emerging as a kind of competitive photocatalysts for hydrogen evolution due to their well-tunable structures, versatile functionalization, and low-cost processibility. In this work, a series of conjugated porous polymers with substantial cyano-substituted fully sp2-carbon frameworks are efficiently synthesized by using electron-deficient tricyanomesitylene as a key building block to promote an organic base-catalyzed Knoevenagel condensation with various aldehyde-substituted arenes. The resulting porous polymers feature donor-acceptor structures with π-extended conjugation, rendering them with distinct semiconducting properties. They possess hierarchically porous structures, nanoscale morphologies, and intriguing wettability. These promising physical characters, finely tailorable by varying the arene units, are essentially relevant to the abundant cynao substituents over the whole frameworks. The as-prepared porous polymers exhibit excellent visible-light-driven photocatalytic activity for water-splitting hydrogen evolution with apparent quantum yield up to 2.0% at 420 nm or 1.9% at 470 nm, among the highest values yet reported for porous polymer-based photocatalysts, also representing the first example of such kinds of catalysts formed through a metal-free-catalyzed carbon–carbon coupling reaction.
Co-reporter:Jinhui Zhu;Jun Yang;Xinliang Feng;Shin-ichi Hirano
Journal of Materials Chemistry A 2017 vol. 5(Issue 32) pp:16732-16739
Publication Date(Web):2017/08/15
DOI:10.1039/C7TA04752E
Two-dimensional (2D) soft materials have attracted much attention recently due to their unique carbon-rich structure and extensive potential applications for energy storage. Although the specific surface areas (SSAs) of 2D soft materials are theoretically high, practically maintaining both the uniform 2D morphology and high SSA of a single 2D soft material is still challenging. Herein, graphene-coupled covalent triazine-based frameworks (G-CTFs) with typical 2D features, large aspect ratio, and ultrahigh SSA of up to 1584 m2 g−1 were synthesized through polymerization of p-benzenedinitrile in molten salt in the presence of p-benzonitrile-functionalized reduced graphene oxide. After their direct pyrolysis, nitrogen-enriched porous carbon nanosheets (G-PCs) can be easily obtained, which had the frameworks' 2D morphology and exhibited a high nitrogen content and even higher SSA of up to 1982/3021 m2 g−1, as calculated using the Brunauer–Emmett–Teller and Langmuir methods, respectively. Benefiting from these features, the G-PCs exhibited excellent energy storage performance as electrode materials in both a Li-ion battery (235 mA h g−1 at 5 A g−1 for 3000 cycles), Na-ion battery (138 mA h g−1 at 1 A g−1 for 500 cycles), and supercapacitor (340 F g−1 at 0.1 A g−1 and 10 000 stable charge–discharge cycles at 5 A g−1). All these results indicate that the 2D sandwich-like porous carbon materials could be promising candidates for high-performance energy storage devices.
Co-reporter:Chenbao Lu;Shaohua Liu;Fan Zhang;Yuezeng Su;Xiaoxin Zou;Zhan Shi;Guodong Li
Journal of Materials Chemistry A 2017 vol. 5(Issue 4) pp:1567-1574
Publication Date(Web):2017/01/24
DOI:10.1039/C6TA09278K
In order to improve the performance and fundamental understanding of conducting polymers, development of new nanotechnologies for engineering aggregated states and morphologies is one of the central focuses for conducting polymers. In this work, we demonstrated an interfacial engineering method for the rational synthesis of a two-dimensional (2D) polyaniline (PANI) nano-array and its corresponding nitrogen-doped porous carbon nanosheets. Not only was it easy to produce a sandwich-like 2D morphology, but also the thickness, anchored ions and produced various metal phosphides were easily and rationally engineered by controlling the composition of the aqueous layer. The novel structural features of these hybrids enabled outstanding electrochemical capacitor performance. The specific capacitance of the as-produced diiron phosphide embedded nitrogen-doped porous carbon nanosheets was calculated to be as high as 1098 F g−1 at 1 A g−1 and an extremely high specific capacitance of 611 F g−1 at 10 A g−1, outperforming state-of-the-art performance among porous carbon and metal-phosphide-based supercapacitors. We believe that this interfacial approach can be extended to the controllable synthesis of various 2D material coupled sandwich-like hybrid materials with potential applications in a wide range of areas.
Co-reporter:Sai Sun;Luxin Wang;Bin Zhang;Junjie Ding;Fan Zhang;Yu Chen
Journal of Materials Chemistry C 2017 vol. 5(Issue 9) pp:2223-2229
Publication Date(Web):2017/03/02
DOI:10.1039/C6TC05362A
Although many molecular-level diodes have exhibited proof-of-concept rectification effect, realization of practical molecular rectifiers still remains a challenge because of unstable and sensitive molecular layers, complicated fabrication methods and not easily accessible measurement techniques. Thus, development of robust and easy procedures for molecular diodes with stable rectification effect is the top priority for the community in this field. Herein, we report a new home-made quasi-molecular rectifier based on a coordinated framework thin film prepared by a layer-by-layer dip-coating method. The as-fabricated rectifier exhibits an average rectification ratio as high as 5.7 and excellent cycle stability over 300 cycles, rendering it a very promising candidate for practical application in comparison with previously reported molecular rectifiers. Besides, such a diode fabrication process can be easily achieved without the aid of expensive scanning tunneling microscopes, precise electrodes approaching operations at an Ångström scale, and other complex techniques. All these results not only demonstrate coordinated frameworks could be good candidates for molecular rectifiers, but also provide a new strategy for fabrication of home-made molecular rectifiers without employing complicated procedures and expensive equipment.
Co-reporter:Luxin Wang, Sai Sun, Bin Zhang, Lingyun Yang, Yefeng Yao, Xiaodong Zhuang, Yu Chen
European Polymer Journal 2017 Volume 94(Volume 94) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.eurpolymj.2017.07.010
•A novel soluble viologen-based conjugated ionic copolymer, PTPA-V, was reported.•PTPA-V based memory device exhibited a non-volatile rewritable memory behavior.•The write and erase voltages are −1.92 and 2.67 V and ON/OFF current ratio exceeds 105.A novel soluble viologen-based conjugated ionic copolymer, PTPA-V, was synthesized by using Suzuki coupling reaction in the presence of the tetrakis(triphenylphosphine)palladium(0) as the catalyst. Its HOMO, LUMO, EA, IP and Eg values derived from the CV data are −5.44, −3.10, 3.07, 5.70 and 2.34 eV, respectively. The maximum absorption peak observed in the UV/Vis absorption spectrum of the PTPA-V thin film was shifted to the red by about 10 nm, suggesting stronger aggregation effect occurred in the thin film. The fluorescence decay profiles of the singlet excited state of PTPA-V in different deaerated organic solvents revealed a mono-exponential decay with a lifetime of 8.9 ns (toluene), 6.4 ns (THF) and 5.2 ns (DMF). The as-prepared electronic device with a configuration of Al/PTPA-V/ITO exhibited two accessible conductivity states, i.e., the high-conductivity (ON) state and the low-conductivity (OFF) state. A typical nonvolatile rewritable memory behavior was observed, with turn-on and turn-off voltages of −1.92 and 2.67 V, and a large ON/OFF current ratio of more than 105. Unlike poly(triphenylamine) without any electron paramagnetic resonance (EPR) signal, PTPA-V shows an EPR signal with a g factor of 2.004, suggesting existence of unpaired electrons or free radicals in this polymer due to the charge transfer between the triphenylamine (TPA) moieties and the viologen (V) moieties, which resulted in the formation of TPA+ and V-.The as-prepared electronic device with a configuration of Al/PTPA-V/ITO exhibits typical nonvolatile storage performance of a bistable rewritable memory device, with turn-on and turn-off voltages of −1.92 and 2.67 V, and a large ON/OFF current ratio exceeding 105.Download high-res image (62KB)Download full-size image
Co-reporter:Xiang Zhu;Tian Jin;Chengcheng Tian;Chenbao Lu;Xiaoming Liu;Min Zeng;Shize Yang;Lin He;Honglai Liu;Sheng Dai
Advanced Materials 2017 Volume 29(Issue 47) pp:
Publication Date(Web):2017/12/01
DOI:10.1002/adma.201704091
AbstractAn in situ coupling approach is developed to create a new highly efficient and durable cobalt-based electrocatalyst for the oxygen evolution reaction (OER). Using a novel cyclotetramerization, a task-specific bimetallic phthalocyanine-based nanoporous organic framework is successfully built as a precursor for the carbonization synthesis of a nonprecious OER electrocatalyst. The resultant material exhibits an excellent OER activity with a low overpotential of 280 mV at a current density of 10 mA cm−2 and high durability in an alkaline medium. This impressive result ranks among the best from known Co-based OER catalysts under the same conditions. The simultaneous installation of multiple diverse cobalt-based active sites, including FeCo alloys and Co4N nanoparticles, plays a critical role in achieving this promising OER performance. This innovative approach not only enables high-performance OER activity to be achieved but simultaneously provides a means to control the surface features, thereby tuning the catalytic property of the material.
Co-reporter:Yuezeng Su;Zhaoquan Yao;Fan Zhang;Hai Wang;Zoltan Mics;Enrique Cánovas;Mischa Bonn;Xinliang Feng
Advanced Functional Materials 2016 Volume 26( Issue 32) pp:5893-5902
Publication Date(Web):
DOI:10.1002/adfm.201602158
Among the rising 2D soft materials, conjugated polymer nanosheets are one of the most promising and new classes of polymeric materials, which are rarely developed because of the challenge in controlling the dimensionality and lack of synthetic strategies. In this study, one kind of sulfur-enriched conjugated polymer nanosheet (2DP-S) with a high aspect ratio of up to ≈400 is successfully synthesized. On the basis of structural characterization, as-prepared 2DP-S possesses the chemical identity of cruciform-fused polymeric backbone consisting of quinoidal polythiophene and poly(p-phenylenevinylene) along horizontal and vertical directions, respectively, by sharing two alternating single–double carbon–carbon bonds in each repeat unit. The unique structural conformation of 2DP-S renders carrier mobilities of up to 0.1 ± 0.05 cm2 V−1 s−1, a figure inferred from Terahertz time domain spectroscopy. Moreover, upon thermal treatment, 2DP-S is readily converted into N/S dual-doped porous carbon nanosheets (2DPCs) under ammonia atmosphere, whose N/S ratio can be rationally controlled by adjusting the activation time. The catalytic performance of the oxygen reduction reaction of as-prepared 2DPCs is well tunable by the rationally controlled N/S contents. These results offer a new pathway for exploring heteroatom-doped porous carbons applicable for energy conversion and storage.
Co-reporter:Ruizhi Tang, Xinyang Wang, Wanzheng Zhang, Xiaodong Zhuang, Shuai Bi, Wenbei Zhang and Fan Zhang
Journal of Materials Chemistry A 2016 vol. 4(Issue 32) pp:7640-7648
Publication Date(Web):18 Jul 2016
DOI:10.1039/C6TC02591A
A series of luminogens comprising one pyridine, 1,3-diazine, 1,4-diazine, 1,2-diazine and phthalazine moiety as the central core and two AIE-active tetraphenylethene units in lateral positions have been readily synthesized by Suzuki cross-coupling. They exhibited remarkably different photophysical and electrochemical properties, as well as solid packing and fine controllability via the number and position of the nitrogen atoms in the aromatic azaheterocycle core. Among them, the pyridine, 1,3-diazine and 1,4-diazine-cored luminogens displayed strong AIE activities, whereas the 1,2-diazine and phthalazine-cored luminogens exhibited almost no AIE effect. The intrinsic Lewis basicity of the as-prepared luminogens endowed them with the ability to fluorometrically detect acids with different pKa values. When protonated by a strong acid such as trifluoroacetic acid, the pyridine, 1,3-diazine and 1,4-diazine-cored luminogens displayed relatively weak AIE effects. In contrast, the 1,2-diazine and phthalazine-cored luminogens exhibited highly sensitive responses to strong acids within a precise pKa range by displaying turn-on fluorescence emissions in the low-energy region, which was probably owing to the synergetic effect of AIE and the constraint of the intersystem crossing effect upon protonation of the 1,2-diazine segment. They displayed reversible acidochromism in response to protonation and deprotonation in the solid state. Such unique properties of the as-prepared luminogens could be used for the selective discrimination of some organic acids, which is highly valuable in the study of biological metabolism.
Co-reporter:Jinhui Zhu, Jun Yang, Rongrong Miao, Zhaoquan Yao, Xiaodong Zhuang and Xinliang Feng
Journal of Materials Chemistry A 2016 vol. 4(Issue 6) pp:2286-2292
Publication Date(Web):11 Jan 2016
DOI:10.1039/C5TA09073C
Nitrogen-doped (N-doped) porous carbons have drawn increasing attention due to their high activity for electrochemical catalysis, and high capacity for lithium-ion (Li-ion) batteries and supercapacitors. So far, the controlled synthesis of N-enriched ordered mesoporous carbons (N-OMCs) for Li-ion batteries is rarely reported due to the lack of a reliable nitrogen-doping protocol that maintains the ordered mesoporous structure. In order to realize this, in this work, ordered mesoporous carbons with controllable N contents were successfully prepared by using melamine, F127 and phenolic resin as the N-source, template and carbon-source respectively via a solvent-free ball-milling method. The as-prepared N-OMCs which showed a high N content up to 31.7 wt% were used as anodes for Li-ion batteries. Remarkably, the N-OMCs with an N content of 24.4 wt% exhibit the highest reversible capacity (506 mA h g−1) even after 300 cycles at 300 mA g−1 and a capacity retention of 103.3%. N-OMCs were also used as electrode materials in supercapacitors and a capacity of 150 F g−1 at 0.2 A g−1 with stable cycling up to 2500 times at 1 A g−1 was achieved. These attractive results encourage the design and synthesis of high heteroatom content ordered porous carbons for applications in the field of energy storage and conversion.
Co-reporter:Hualin Lin, Fan Liu, Xinjing Wang, Yani Ai, Zhaoquan Yao, Lei Chu, Sheng Han, Xiaodong Zhuang
Electrochimica Acta 2016 Volume 191() pp:705-715
Publication Date(Web):10 February 2016
DOI:10.1016/j.electacta.2016.01.064
Graphene-coupled flower-like nickel sulfide monoliths that exhibit ultra-light, mesoporous structures and uniform particle sizes are successfully prepared using an F127-assisted hydrothermal method and high-temperature pyrolysis. As an electrode material for supercapacitors, the as-prepared rGO-Ni3S2 shows ultra-high specific capacitances of 1315 and 1050 F g−1 at 1 and 10 A g−1, respectively. After 1000 charge/discharge cycles at a current density of 1 A g−1, the specific capacitance increases by almost 15%, indicating the excellent capacitance and durability of rGO-Ni3S2. Further, an asymmetric supercapacitor using rGO-Ni3S2 as positive electrode and active carbon as negative electrode exhibits high specific capacitance of 104.6 F g−1 at 0.5 A g−1, and excellent cycling stability with 85.6% capacitance retention after 5000 cycles at a current density of 4 A g−1. These promising supercapacitor performances demonstrate that the as-developed surfactant-assisted hydrothermal strategy can be widely used to prepare graphene-coupled metal sulfides for high-performance supercapacitor applications.
Co-reporter:Ruizhi Tang, Xinyang Wang, Wanzheng Zhang, Xiaodong Zhuang, Shuai Bi, Wenbei Zhang, Yiyong Mai and Fan Zhang
RSC Advances 2016 vol. 6(Issue 80) pp:76691-76695
Publication Date(Web):02 Aug 2016
DOI:10.1039/C6RA16631H
A luminogen (ITP-TPE) comprising isothianaphthene-bridged tetraphenylethene units was efficiently synthesized. Its unique extended π-conjugated structure allows for colorimetric and off/on fluorescent detection for Cu2+ with extremely high selectivity and sensitivity, by the formation of nonarylamine-based organic mixed-valence state.
Co-reporter:Zhaoquan Yao, Yuezeng Su, Chenbao Lu, Chongqing Yang, Zhixiao Xu, Jinhui Zhu, Xiaodong Zhuang and Fan Zhang
New Journal of Chemistry 2016 vol. 40(Issue 7) pp:6015-6021
Publication Date(Web):30 Mar 2016
DOI:10.1039/C5NJ03440J
We first developed a new two-dimensional graphene-based Schiff-base porous polymer by the condensation of melamin, 1,4-phthalaldehyde and aminated graphene oxide. Then, we prepared a new family of two-dimensional molybdenum phosphide-containing porous carbons (TPC–MoPs) by using the as-prepared two-dimensional porous polymer (TPP) as a two-dimensional template, and low-cost diammonium phosphate and ammonium molybdate as precursors through stepwise self-assembly and pyrolysis. The resulting TPC–MoPs featured layered and porous structures with high specific surface areas of up to 72 m2 g−1. The unique mophology characteristics render such kinds of materials with increased active catalytic sites and better conductivity, as compared with the other MoPs-based composites. As a consequence, the as-prepared composites exhibit superior electrocatalytic performance in the hydrogen evolution reaction (HER) under acidic conditions, with a Tafel slope of 68.5 mV dec−1, a low onset overpotential of 65 mV (versus the reversible hydrogen electrode), and a large exchange current density (j0) of 0.144 mA cm−2.
Co-reporter:Sheng Han;Yunlong Feng;Fan Zhang;Chongqing Yang;Zhaoquan Yao;Wuxue Zhao;Feng Qiu;Lingyun Yang;Yefeng Yao;Xinliang Feng
Advanced Functional Materials 2015 Volume 25( Issue 25) pp:3899-3906
Publication Date(Web):
DOI:10.1002/adfm.201501390
A novel phosphorus-containing porous polymer is efficiently prepared from tris(4-vinylphenyl)phosphane by radical polymerization, and it can be easily ionized to form an ionic porous polymer after treatment with hydrogen iodide. Upon ionic exchange, transition-metal-containing anions, such as tetrathiomolybdate (MoS4 2−) and hexacyanoferrate (Fe(CN)6 3−), are successfully loaded into the framework of the porous polymer to replace the original iodide anions, resulting in a polymer framework containing complex anions (termed HT-Met, where Met = Mo or Fe). After pyrolysis under a hydrogen atmosphere, the HT-Met materials are efficiently converted at a large scale to metal-phosphide-containing porous carbons (denoted as MetP@PC, where again Met = Mo or Fe). This approach provides a convenient pathway to the controlled preparation of metal-phosphide-loaded porous carbon composites. The MetP@PC composites exhibit superior electrocatalytic activity for the hydrogen evolution reaction (HER) under acidic conditions. In particular, MoP@PC with a low loading of 0.24 mg cm−2 (on a glass carbon electrode) affords an iR-corrected (where i is current and R is resistance) current density of up to 10 mA cm−2 at 51 mV versus the reversible hydrogen electrode and a very low Tafel slope of 45 mV dec−1, in rotating disk measurements under saturated N2 conditions.
Co-reporter:Wuxue Zhao, Sheng Han, Xiaodong Zhuang, Fan Zhang, Yiyong Mai and Xinliang Feng
Journal of Materials Chemistry A 2015 vol. 3(Issue 46) pp:23352-23359
Publication Date(Web):09 Oct 2015
DOI:10.1039/C5TA06702B
A new series of B, N-containing cross-linked polymers (PPs-BN) were achieved via Sonogashira cross coupling. These polymers exhibit very high carbon yields of around 70–80% even at 800 °C, which allow them to be efficiently converted to B/N co-doped porous carbons after pyrolysis at high temperature under an inert atmosphere. The materials have been fully characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analyses, nitrogen sorption measurements and X-ray photoelectron spectroscopy, revealing their high contents of boron and nitrogen up to ∼3.21% and ∼5.72%, respectively, as well as porous structures with the largest specific surface area of 291 m2 g−1. Their CO2 capacities reached 3.25 mmol g−1 at 273 K under 1 atm. In addition, the very high selectivity for CO2/CH4 with a ratio of more than 5:1 at 298 K renders them applicable for gas separation and purification.
Co-reporter:Wuxue Zhao, Zongsheng Hou, Zhaoquan Yao, Xiaodong Zhuang, Fan Zhang and Xinliang Feng
Polymer Chemistry 2015 vol. 6(Issue 40) pp:7171-7178
Publication Date(Web):26 Aug 2015
DOI:10.1039/C5PY01194A
Two-dimensional hyper-cross-linked microporous polymers (2D HCPs) have been readily synthesized by emulsion polymerization using trithiocarbonate functionalized graphene oxide as a 2D reversible addition–fragmentation chain transfer (RAFT) agent. After a gel-type and permanently porous poly(vinylbenzyl chloride-co-divinylbenzene) precursor resin was grafted to the graphene surface, an FeCl3-promoted Friedel–Crafts reaction was carried out for benzyl chloride groups to construct a porous structure confined within 2D nanosheets. The resulting HCPs exhibited superhydrophobic behavior, and had a predominance of micropores with a specific surface area of up to 1224 m2 g−1. Moreover, they showed improved thermal stability in comparison with unadorned HCPs obtained without using the graphene template. Their H2 and CO2 capacities at 77 and 273 K reached 1.27 and 9.74 wt%, respectively, at a relative pressure of 0.99. In addition, the as-synthesized 2D HCPs were used as carbon precursors to generate 2D porous carbons with a high specific surface area (871 m2 g−1) and high-performance electrochemical energy storage (144 F g−1 at 0.5 A g−1).
Co-reporter:Sai Sun, Xiaodong Zhuang, Luxin Wang, Bo Liu, Bin Zhang, Yu Chen
Carbon (May 2017) Volume 116() pp:
Publication Date(Web):May 2017
DOI:10.1016/j.carbon.2017.02.034
The data storage performance, stability and reliability of the graphene memories have advanced significantly towards practical information storage applications. Using highly dispersed 4-bromobenzene functionalized RGO (BB-RGO) as two dimensional template, a new poly[(1,4-diethynylbenzene)-alt-boron dipyrro-methene]-grafted reduced graphene oxide (PDBD-g-RGO) was synthesized via Sonogashira coupling reaction. Covalent grafting of PDBD onto BB-RGO gives rise to a 34-cm−1 blue shift of the D band and a 7-cm−1 red shift of the G band when compared to the Raman spectrum of BB-RGO. A transparent and flexible nonvolatile memory device with configuration of Al/PDBD-g-RGO/ITO-coated poly(ethylene terephthalate) (PET) exhibited typical storage performance of rewritable memory that can be electrically erased and reprogrammed, with turn-on and turn-off voltages of 1.55 and −1.80 V, and an ON/OFF current ratio exceeding 105. The memory behaviors of the flexible device were almost unchanged under the bending test.A new poly[(1,4-diethynylbenzene)-alt-boron dipyrromethene]-grafted RGO (PDBD-g-RGO) was synthesized. This material-based memory device exhibited typical storage performance of rewritable memory, with turn-on and turn-off voltages of 1.55 and −1.80 V, and an ON/OFF current ratio of more than 105.
Co-reporter:Wenbei Zhang, Tianlu Cui, Lingyun Yang, Chao Zhang, Ming Cai, Sai Sun, Yefeng Yao, Xiaodong Zhuang, Fan Zhang
Journal of Colloid and Interface Science (1 July 2017) Volume 497() pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.jcis.2017.02.061
•Conjugated porous polymer spheres with hollow structure (HCMP-Fe) were prepared.•A series of Fe/N-doped hierarchical porous carbons derived from HCMP-Fe were prepared.•The as-prepared catalyst exhibited promising electrochemical performance for ORR.Iron and nitrogen (Fe/N) co-doped porous carbons have already shown great potential as electrocatalysts for oxygen reduction reaction in alkaline media. However, it still remains a great challenge to finely integrate a hierarchical porous structure and Fe/N co-doping effect into one material at the same time. In this work, a rational design toward Fe/N-codoped hierarchical porous carbon spheres was developed by the formation of an iron-porphyrin-containing conjugated microporous polymer sphere with hollow structure (HCMP) through a silica sphere template directed condensation of pyrrole and 1,4-phthalaldehyde, then etched with NaOH, and treated with FeCl2. The resulting HCMP-Fe polymer was readily converted to a series of Fe/N co-doped hierarchical porous carbons (HPC-Fe/N-X, X = 700–900) upon pyrolysis at different temperatures and etching treatment. These porous carbons exhibit the high specific surface areas up to 518 m2 g−1 and the contents of N and Fe up to 3.28 at.% and 0.85 wt.%, respectively. Benefiting from the high surface area, Fe/N co-doping character, HPC-Fe/N-700 exhibited excellent electrochemical catalytic performance for oxygen reduction reaction under alkaline condition (0.1 M KOH) with a low half-wave potential (0.84 V), a dominant four-electron transfer mechanism (n = 3.89 at 0.65 V), as well as a high diffusion limiting current density (JL = 5.19 mA cm−2), comparable to those porous carbon-based ORR catalysts with excellent electrochemical performance.A rational design toward Fe/N-codoped hierarchical porous carbon spheres with hollow structure was developed by using conjugated microporous polymer and silica sphere as precursor and template respectively.
Co-reporter:Sai Sun, Xiaodong Zhuang, Luxin Wang, Bin Zhang, Junjie Ding, Fan Zhang and Yu Chen
Journal of Materials Chemistry A 2017 - vol. 5(Issue 9) pp:NaN2229-2229
Publication Date(Web):2017/01/30
DOI:10.1039/C6TC05362A
Although many molecular-level diodes have exhibited proof-of-concept rectification effect, realization of practical molecular rectifiers still remains a challenge because of unstable and sensitive molecular layers, complicated fabrication methods and not easily accessible measurement techniques. Thus, development of robust and easy procedures for molecular diodes with stable rectification effect is the top priority for the community in this field. Herein, we report a new home-made quasi-molecular rectifier based on a coordinated framework thin film prepared by a layer-by-layer dip-coating method. The as-fabricated rectifier exhibits an average rectification ratio as high as 5.7 and excellent cycle stability over 300 cycles, rendering it a very promising candidate for practical application in comparison with previously reported molecular rectifiers. Besides, such a diode fabrication process can be easily achieved without the aid of expensive scanning tunneling microscopes, precise electrodes approaching operations at an Ångström scale, and other complex techniques. All these results not only demonstrate coordinated frameworks could be good candidates for molecular rectifiers, but also provide a new strategy for fabrication of home-made molecular rectifiers without employing complicated procedures and expensive equipment.
Co-reporter:Ruizhi Tang, Xinyang Wang, Wanzheng Zhang, Xiaodong Zhuang, Shuai Bi, Wenbei Zhang and Fan Zhang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 32) pp:NaN7648-7648
Publication Date(Web):2016/07/18
DOI:10.1039/C6TC02591A
A series of luminogens comprising one pyridine, 1,3-diazine, 1,4-diazine, 1,2-diazine and phthalazine moiety as the central core and two AIE-active tetraphenylethene units in lateral positions have been readily synthesized by Suzuki cross-coupling. They exhibited remarkably different photophysical and electrochemical properties, as well as solid packing and fine controllability via the number and position of the nitrogen atoms in the aromatic azaheterocycle core. Among them, the pyridine, 1,3-diazine and 1,4-diazine-cored luminogens displayed strong AIE activities, whereas the 1,2-diazine and phthalazine-cored luminogens exhibited almost no AIE effect. The intrinsic Lewis basicity of the as-prepared luminogens endowed them with the ability to fluorometrically detect acids with different pKa values. When protonated by a strong acid such as trifluoroacetic acid, the pyridine, 1,3-diazine and 1,4-diazine-cored luminogens displayed relatively weak AIE effects. In contrast, the 1,2-diazine and phthalazine-cored luminogens exhibited highly sensitive responses to strong acids within a precise pKa range by displaying turn-on fluorescence emissions in the low-energy region, which was probably owing to the synergetic effect of AIE and the constraint of the intersystem crossing effect upon protonation of the 1,2-diazine segment. They displayed reversible acidochromism in response to protonation and deprotonation in the solid state. Such unique properties of the as-prepared luminogens could be used for the selective discrimination of some organic acids, which is highly valuable in the study of biological metabolism.
Co-reporter:Jinhui Zhu, Jun Yang, Rongrong Miao, Zhaoquan Yao, Xiaodong Zhuang and Xinliang Feng
Journal of Materials Chemistry A 2016 - vol. 4(Issue 6) pp:NaN2292-2292
Publication Date(Web):2016/01/11
DOI:10.1039/C5TA09073C
Nitrogen-doped (N-doped) porous carbons have drawn increasing attention due to their high activity for electrochemical catalysis, and high capacity for lithium-ion (Li-ion) batteries and supercapacitors. So far, the controlled synthesis of N-enriched ordered mesoporous carbons (N-OMCs) for Li-ion batteries is rarely reported due to the lack of a reliable nitrogen-doping protocol that maintains the ordered mesoporous structure. In order to realize this, in this work, ordered mesoporous carbons with controllable N contents were successfully prepared by using melamine, F127 and phenolic resin as the N-source, template and carbon-source respectively via a solvent-free ball-milling method. The as-prepared N-OMCs which showed a high N content up to 31.7 wt% were used as anodes for Li-ion batteries. Remarkably, the N-OMCs with an N content of 24.4 wt% exhibit the highest reversible capacity (506 mA h g−1) even after 300 cycles at 300 mA g−1 and a capacity retention of 103.3%. N-OMCs were also used as electrode materials in supercapacitors and a capacity of 150 F g−1 at 0.2 A g−1 with stable cycling up to 2500 times at 1 A g−1 was achieved. These attractive results encourage the design and synthesis of high heteroatom content ordered porous carbons for applications in the field of energy storage and conversion.
Co-reporter:Wuxue Zhao, Sheng Han, Xiaodong Zhuang, Fan Zhang, Yiyong Mai and Xinliang Feng
Journal of Materials Chemistry A 2015 - vol. 3(Issue 46) pp:NaN23359-23359
Publication Date(Web):2015/10/09
DOI:10.1039/C5TA06702B
A new series of B, N-containing cross-linked polymers (PPs-BN) were achieved via Sonogashira cross coupling. These polymers exhibit very high carbon yields of around 70–80% even at 800 °C, which allow them to be efficiently converted to B/N co-doped porous carbons after pyrolysis at high temperature under an inert atmosphere. The materials have been fully characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analyses, nitrogen sorption measurements and X-ray photoelectron spectroscopy, revealing their high contents of boron and nitrogen up to ∼3.21% and ∼5.72%, respectively, as well as porous structures with the largest specific surface area of 291 m2 g−1. Their CO2 capacities reached 3.25 mmol g−1 at 273 K under 1 atm. In addition, the very high selectivity for CO2/CH4 with a ratio of more than 5:1 at 298 K renders them applicable for gas separation and purification.
Co-reporter:Chenbao Lu, Shaohua Liu, Fan Zhang, Yuezeng Su, Xiaoxin Zou, Zhan Shi, Guodong Li and Xiaodong Zhuang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 4) pp:NaN1574-1574
Publication Date(Web):2016/12/05
DOI:10.1039/C6TA09278K
In order to improve the performance and fundamental understanding of conducting polymers, development of new nanotechnologies for engineering aggregated states and morphologies is one of the central focuses for conducting polymers. In this work, we demonstrated an interfacial engineering method for the rational synthesis of a two-dimensional (2D) polyaniline (PANI) nano-array and its corresponding nitrogen-doped porous carbon nanosheets. Not only was it easy to produce a sandwich-like 2D morphology, but also the thickness, anchored ions and produced various metal phosphides were easily and rationally engineered by controlling the composition of the aqueous layer. The novel structural features of these hybrids enabled outstanding electrochemical capacitor performance. The specific capacitance of the as-produced diiron phosphide embedded nitrogen-doped porous carbon nanosheets was calculated to be as high as 1098 F g−1 at 1 A g−1 and an extremely high specific capacitance of 611 F g−1 at 10 A g−1, outperforming state-of-the-art performance among porous carbon and metal-phosphide-based supercapacitors. We believe that this interfacial approach can be extended to the controllable synthesis of various 2D material coupled sandwich-like hybrid materials with potential applications in a wide range of areas.
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