共查询到20条相似文献,搜索用时 15 毫秒
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Dr. Yukun Zhu Chunxiao Lv Zhuocheng Yin Prof. Jun Ren Prof. Xianfeng Yang Prof. Chung-Li Dong Prof. Hongwei Liu Dr. Rongsheng Cai Yu-Cheng Huang Prof. Wolfgang Theis Prof. Shaohua Shen Prof. Dongjiang Yang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(2):878-883
Red phosphorus is a promising photocatalyst with wide visible-light absorption up to 700 nm, but the fast charge recombination limits its photocatalytic hydrogen evolution reaction (HER) activity. Now, [001]-oriented Hittorf's phosphorus (HP) nanorods were successfully grown on polymeric carbon nitride (PCN) by a chemical vapor deposition strategy. Compared with the bare PCN and HP, the optimized PCN@HP hybrid exhibited a significantly enhanced photocatalytic activity, with HER rates reaching 33.2 and 17.5 μmol h−1 from pure water under simulated solar light and visible light irradiation, respectively. It was theoretically and experimentally indicated that the strong electronic coupling between PCN and [001]-oriented HP nanorods gave rise to the enhanced visible light absorption and the greatly accelerated photoinduced electron–hole separation and transfer, which benefited the photocatalytic HER performance. 相似文献
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Souvik Roy Erwin Reisner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12308-12312
The integration of molecular catalysts with low‐cost, solid light absorbers presents a promising strategy to construct catalysts for the generation of solar fuels. Here, we report a photocatalyst for CO2 reduction that consists of a polymeric cobalt phthalocyanine catalyst (CoPPc) coupled with mesoporous carbon nitride (mpg‐CNx) as the photosensitizer. This precious‐metal‐free hybrid catalyst selectively converts CO2 to CO in organic solvents under UV/Vis light (AM 1.5G, 100 mW cm?2, λ>300 nm) with a cobalt‐based turnover number of 90 for CO after 60 h. Notably, the photocatalyst retains 60 % CO evolution activity under visible light irradiation (λ>400 nm) and displays moderate water tolerance. The in situ polymerization of the phthalocyanine allows control of catalyst loading and is key for achieving photocatalytic CO2 conversion. 相似文献
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Zhiming Pan Guigang Zhang Xinchen Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(21):7176-7180
The charge transfer between hydrogen evolution photocatalysts (HEPs) and oxygen evolution photocatalysts (OEPs) is the rate‐determining step that controls the overall performance of a Z‐scheme water‐splitting system. Here, we carefully design reduced graphene oxide (RGO) nanosheets for use as solid‐state mediators to accelerate the charge carrier transfer between HEPs (e.g., polymeric carbon nitride (PCN)) and OEPs (e.g., Fe2O3), thus achieving efficient overall water splitting. The important role of RGO could also be further proven in other PCN‐based Z‐systems (BiVO4/RGO/PCN and WO3/RGO/PCN), illustrating the universality of this strategy. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(32):9464-9468
Photocatalytic Diels–Alder (D–A) reactions with electron rich olefins are realized by graphitic carbon nitride (g‐C3N4) under visible‐light irradiation and aerobic conditions. This heterogeneous photoredox reaction system is highly efficient, and the apparent quantum yield reaches a remarkable value of 47 % for the model reaction. Dioxygen plays a critical role as electron mediator, which is distinct from the previous reports in the homogeneous RuII complex photoredox system. Moreover, the reaction intermediate vinylcyclobutane is captured and monitored during the reaction, serving as a direct evidence for the proposed reaction mechanism. The cycloaddition process is thereby determined to be the combination of direct [4+2] cycloaddition and [2+2] cycloaddition followed by photocatalytic rearrangement of the vinylcyclobutane intermediate. 相似文献
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Visible‐Light‐Driven Hydrogen Evolution Using Planarized Conjugated Polymer Photocatalysts
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Dr. Reiner Sebastian Sprick Dr. Baltasar Bonillo Rob Clowes Pierre Guiglion Nick J. Brownbill Dr. Benjamin J. Slater Dr. Frédéric Blanc Dr. Martijn A. Zwijnenburg Prof. Dave J. Adams Prof. Andrew I. Cooper 《Angewandte Chemie (International ed. in English)》2016,55(5):1792-1796
Linear poly(p‐phenylene)s are modestly active UV photocatalysts for hydrogen production in the presence of a sacrificial electron donor. Introduction of planarized fluorene, carbazole, dibenzo[b,d]thiophene or dibenzo[b,d]thiophene sulfone units greatly enhances the H2 evolution rate. The most active dibenzo[b,d]thiophene sulfone co‐polymer has a UV photocatalytic activity that rivals TiO2, but is much more active under visible light. The dibenzo[b,d]thiophene sulfone co‐polymer has an apparent quantum yield of 2.3 % at 420 nm, as compared to 0.1 % for platinized commercial pristine carbon nitride. 相似文献
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Covalent Photosensitizer–Polyoxometalate‐Catalyst Dyads for Visible‐Light‐Driven Hydrogen Evolution
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Joachim Kübel Mathias Micheel Prof. Dr. Benjamin Dietzek Prof. Dr. Sven Rau Prof. Dr. Carsten Streb 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(34):12002-12005
A general concept for the covalent linkage of coordination compounds to bipyridine‐functionalized polyoxometalates is presented. The new route is used to link an iridium photosensitizer to an Anderson‐type hydrogen‐evolution catalyst. This covalent dyad catalyzes the visible‐light‐driven hydrogen evolution reaction (HER) and shows superior HER activity compared with the non‐covalent reference. Hydrogen evolution is observed over periods >1 week. Spectroscopic, photophysical, and electrochemical analyses give initial insight into the stability, electronic structure, and reactivity of the dyad. The results demonstrate that the proposed linkage concept allows synergistic covalent interactions between functional coordination compounds and reactive molecular metal oxides. 相似文献
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Gerardo Algara‐Siller Nikolai Severin Samantha Y. Chong Torbjrn Bjrkman Robert G. Palgrave Andrea Laybourn Markus Antonietti Yaroslav Z. Khimyak Arkady V. Krasheninnikov Jürgen P. Rabe Ute Kaiser Andrew I. Cooper Arne Thomas Michael J. Bojdys 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(29)
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(43):13630-13634
Polymeric or organic semiconductors are promising candidates for photocatalysis but mostly only show moderate activity owing to strongly bound excitons and insufficient optical absorption. Herein, we report a facile bottom‐up strategy to improve the activity of a carbon nitride to a level in which a majority of photons are really used to drive photoredox chemistry. Co‐condensation of urea and oxamide followed by post‐calcination in molten salt is shown to result in highly crystalline species with a maximum π–π layer stacking distance of heptazine units of 0.292 nm, which improves lateral charge transport and interlayer exciton dissociation. The addition of oxamide decreases the optical band gap from 2.74 to 2.56 eV, which enables efficient photochemistry also with green light. The apparent quantum yield (AQY) for H2 evolution of optimal samples reaches 57 % and 10 % at 420 nm and 525 nm, respectively, which is significantly higher than in most previous experiments. 相似文献
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Corrigendum: Visible‐Light‐Driven Hydrogen Evolution Using Planarized Conjugated Polymer Photocatalysts
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Dr. Reiner Sebastian Sprick Dr. Baltasar Bonillo Rob Clowes Pierre Guiglion Nick J. Brownbill Dr. Benjamin J. Slater Dr. Frédéric Blanc Dr. Martijn A. Zwijnenburg Prof. Dave J. Adams Prof. Andrew I. Cooper 《Angewandte Chemie (International ed. in English)》2018,57(10):2520-2520
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Narrow‐Bandgap Chalcogenoviologens for Electrochromism and Visible‐Light‐Driven Hydrogen Evolution
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Guoping Li Letian Xu Weidong Zhang Kun Zhou Yousong Ding Dr. Fenglin Liu Prof. Dr. Xiaoming He Prof. Dr. Gang He 《Angewandte Chemie (International ed. in English)》2018,57(18):4897-4901
A series of electron‐accepting chalcogen‐bridged viologens with narrow HOMO–LUMO bandgaps and low LUMO levels is reported. The optoelectronic properties of chalcogenoviologens can be readily tuned through heavy atom substitution (S, Se and Te). Herein, in situ electrochemical spectroscopy was performed on the proof‐of‐concept electrochromic devices (ECD). E‐BnV2+ (E=Se, Te; BnV2+=benzyl viologen) was used for the visible‐light‐driven hydrogen evolution due to the strong visible‐light absorption. Remarkably, E‐BnV2+ was not only used as a photosensitizer, but also as an electron mediator, providing a new strategy to explore photocatalysts. The higher apparent quantum yield of Se‐BnV2+ could be interpreted in terms of different energy levels, faster electron‐transfer rates and faster formation of radical species. 相似文献
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Phosphorus‐Doped Carbon Nitride Tubes with a Layered Micro‐nanostructure for Enhanced Visible‐Light Photocatalytic Hydrogen Evolution
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Shien Guo Dr. Zhaopeng Deng Dr. Mingxia Li Dr. Baojiang Jiang Prof. Chungui Tian Prof. Qingjiang Pan Prof. Honggang Fu 《Angewandte Chemie (International ed. in English)》2016,55(5):1830-1834
Phosphorus‐doped hexagonal tubular carbon nitride (P‐TCN) with the layered stacking structure was obtained from a hexagonal rod‐like single crystal supramolecular precursor (monoclinic, C2/m). The production process of P‐TCN involves two steps: 1) the precursor was prepared by self‐assembly of melamine with cyanuric acid from in situ hydrolysis of melamine under phosphorous acid‐assisted hydrothermal conditions; 2) the pyrolysis was initiated at the center of precursor under heating, thus giving the hexagonal P‐TCN. The tubular structure favors the enhancement of light scattering and active sites. Meanwhile, the introduction of phosphorus leads to a narrow band gap and increased electric conductivity. Thus, the P‐TCN exhibited a high hydrogen evolution rate of 67 μmol h?1 (0.1 g catalyst, λ >420 nm) in the presence of sacrificial agents, and an apparent quantum efficiency of 5.68 % at 420 nm, which is better than most of bulk g‐C3N4 reported. 相似文献
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Visible‐Light‐Driven CO2 Reduction with Carbon Nitride: Enhancing the Activity of Ruthenium Catalysts
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Ryo Kuriki Dr. Keita Sekizawa Prof. Dr. Osamu Ishitani Prof. Dr. Kazuhiko Maeda 《Angewandte Chemie (International ed. in English)》2015,54(8):2406-2409
A heterogeneous photocatalyst system that consists of a ruthenium complex and carbon nitride (C3N4), which act as the catalytic and light‐harvesting units, respectively, was developed for the reduction of CO2 into formic acid. Promoting the injection of electrons from C3N4 into the ruthenium unit as well as strengthening the electronic interactions between the two units enhanced its activity. The use of a suitable solvent further improved the performance, resulting in a turnover number of greater than 1000 and an apparent quantum yield of 5.7 % at 400 nm. These are the best values that have been reported for heterogeneous photocatalysts for CO2 reduction under visible‐light irradiation to date. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(31):9938-9942
Photocatalytic water splitting for hydrogen production using sustainable sunlight is a promising alternative to industrial hydrogen production. However, the scarcity of highly active, recyclable, inexpensive photocatalysts impedes the development of photocatalytic hydrogen evolution reaction (HER) schemes. Herein, a metal–organic framework (MOF)‐template strategy was developed to prepare non‐noble metal co‐catalyst/solid solution heterojunction NiS/ZnxCd1−xS with superior photocatalytic HER activity. By adjusting the doping metal concentration in MOFs, the chemical compositions and band gaps of the heterojunctions can be fine‐tuned, and the light absorption capacity and photocatalytic activity were further optimized. NiS/Zn0.5Cd0.5S exhibits an optimal HER rate of 16.78 mmol g−1 h−1 and high stability and recyclability under visible‐light irradiation (λ>420 nm). Detailed characterizations and in‐depth DFT calculations reveal the relationship between the heterojunction and photocatalytic activity and confirm the importance of NiS in accelerating the water dissociation kinetics, which is a crucial factor for photocatalytic HER. 相似文献
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Yu Noda Christoph Merschjann Jn Tarbek Patrick Amsalem Norbert Koch Michael J. Bojdys 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(28):9494-9498
Triazine‐based graphitic carbon nitride (TGCN) is the most recent addition to the family of graphene‐type, two‐dimensional, and metal‐free materials. Although hailed as a promising low‐band‐gap semiconductor for electronic applications, so far, only its structure and optical properties have been known. Here, we combine direction‐dependent electrical measurements and time‐resolved optical spectroscopy to determine the macroscopic conductivity and microscopic charge‐carrier mobilities in this layered material “beyond graphene”. Electrical conductivity along the basal plane of TGCN is 65 times lower than through the stacked layers, as opposed to graphite. Furthermore, we develop a model for this charge‐transport behavior based on observed carrier dynamics and random‐walk simulations. Our combined methods provide a path towards intrinsic charge transport in a direction‐dependent layered semiconductor for applications in field‐effect transistors (FETs) and sensors. 相似文献
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Weikang Wang Haimin Zhang Shengbo Zhang Yanyan Liu Guozhong Wang Chenghua Sun Huijun Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(46):16797-16803
As a metal‐free nitrogen reduction reaction (NRR) photocatalyst, g‐C3N4 is available from a scalable synthesis at low cost. Importantly, it can be readily functionalized to enhance photocatalytic activities. However, the use of g‐C3N4‐based photocatalysts for the NRR has been questioned because of the elusive mechanism and the involvement of N defects. This work reports the synthesis of a g‐C3N4 photocatalyst modified with cyano groups and intercalated K+ (mCNN), possessing extended visible‐light harvesting capacity and superior photocatalytic NRR activity (NH3 yield: 3.42 mmol g?1 h?1). Experimental and theoretical studies suggest that the ‐C≡N in mCNN can be regenerated through a pathway analogous to Mars van Krevelen process with the aid of the intercalated K+. The results confirm that the regeneration of the cyano group not only enhances photocatalytic activity and sustains the catalytic cycle, but also stabilizes the photocatalyst. 相似文献