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1.
Liming Sun Yuan Zhuang Yusheng Yuan Wenwen Zhan Xiao‐Jun Wang Xiguang Han Yanli Zhao 《Liver Transplantation》2019,9(48)
CuO as a catalyst has shown promising application prospects in photocatalytic splitting of water into hydrogen (H2). However, the instability of CuO in amine aqueous solution limits the applications of CuO‐based photocatalysts in the photocatalytic H2 evolution. In this work, a novel dodecahedral nitrogen (N)‐doped carbon (C) coated CuO‐In2O3 p–n heterojunction (DNCPH) is designed and synthesized by directly pyrolyzing benzimidazole‐modified dodecahedral Cu/In‐based metal‐organic frameworks, showing long‐term stability in triethanolamine (TEOA) aqueous solution and excellent photocatalytic H2 production efficiency. The improved stability of DNCPH in TEOA solution is ascribed to the alleviation of electron deficiency in CuO by forming the p–n heterojunction and the protection with coated N‐doped C layer. Based on detailed theoretical calculations and experimental studies, it is found that the improved separation efficiency of photogenerated electron/hole pairs and the mediated adsorption behavior (|?GH*|→0) by coupling N‐doped C layer with CuO‐In2O3 p–n heterojunction lead to the excellent photocatalytic H2 production efficiency of DNCPH. This work provides a feasible strategy for effectively applying CuO‐based photocatalysts in photocatalytic H2 production. 相似文献
2.
Leaf‐Mosaic‐Inspired Vine‐Like Graphitic Carbon Nitride Showing High Light Absorption and Efficient Photocatalytic Hydrogen Evolution 下载免费PDF全文
Yi Zhang Lanlan Wu Xinyu Zhao Yingnan Zhao Huaqiao Tan Xia Zhao Yuanyuan Ma Zhao Zhao Shuyan Song Yonghui Wang Yangguang Li 《Liver Transplantation》2018,8(25)
Green plants use solar energy efficiently in nature. Simulating the exquisite structure of a natural photosynthesis system may open a new approach for the construction of desirable photocatalysts with high light harvesting efficiency and performance. Herein, inspired by the excellent light utilization of “leaf mosaic” in plants, a novel vine‐like g‐C3N4 (V‐CN) is synthesized for the first time by copolymerizing urea with dicyandiamide‐formaldehyde (DF) resin. The as‐prepared V‐CN exhibits ultrahigh photocatalytic hydrogen production of 13.6 mmol g?1 h?1 under visible light and an apparent quantum yield of 12.7% at 420 nm, which is ≈38 times higher than that of traditional g‐C3N4, representing one of the highest‐activity g‐C3N4‐based photocatalysts. This super photocatalytic performance is derived from the unique leaf mosaic structure of V‐CN, which effectively improves its light utilization and affords a larger specific surface area. In addition, the introduction of DF resin further optimizes the energy band of V‐CN, extends its light absorption, and improves its crystallinity and interfacial charge transport, resulting in high performance. It is an easy and green strategy for the preparation of broad‐spectrum, high‐performance g‐C3N4, which presents significant advancement for the design of other nanophotocatalysts by simulating the fine structure of natural photosynthesis. 相似文献
3.
Urea‐Modified Carbon Nitrides: Enhancing Photocatalytic Hydrogen Evolution by Rational Defect Engineering 下载免费PDF全文
Vincent Wing‐hei Lau Victor Wen‐zhe Yu Florian Ehrat Tiago Botari Igor Moudrakovski Thomas Simon Viola Duppel Elise Medina Jacek K. Stolarczyk Jochen Feldmann Volker Blum Bettina V. Lotsch 《Liver Transplantation》2017,7(12)
The primary amine groups on the heptazine‐based polymer melon, also known as graphitic carbon nitride (g‐C3N4), can be replaced by urea groups using a two‐step postsynthetic functionalization. Under simulated sunlight and optimum Pt loading, this urea‐functionalized carbon nitride has one of the highest activities among organic and polymeric photocatalysts for hydrogen evolution with methanol as sacrificial donor, reaching an apparent quantum efficiency of 18% and nearly 30 times the hydrogen evolution rate compared to the nonfunctionalized counterpart. In the absence of Pt, the urea‐derivatized material evolves hydrogen at a rate over four times that of the nonfunctionalized one. Since “defects” are conventionally accepted to be the active sites in graphitic carbon nitride for photocatalysis, the work here is a demonstrated example of “defect engineering,” where the catalytically relevant defect is inserted rationally for improving the intrinsic, rather than extrinsic, photocatalytic performance. Furthermore, the work provides a retrodictive explanation for the general observation that g‐C3N4 prepared from urea performs better than those prepared from dicyandiamide and melamine. In‐depth analyses of the spent photocatalysts and computational modeling suggest that inserting the urea group causes a metal‐support interaction with the Pt cocatalyst, thus facilitating interfacial charge transfer to the hydrogen evolving centers. 相似文献
4.
Exceptional Visible‐Light‐Driven Cocatalyst‐Free Photocatalytic Activity of g‐C3N4 by Well Designed Nanocomposites with Plasmonic Au and SnO2
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Amir Zada Muhammad Humayun Fazal Raziq Xuliang Zhang Yang Qu Linlu Bai Chuanli Qin Liqiang Jing Honggang Fu 《Liver Transplantation》2016,6(21)
In this work, plasmonic Au/SnO2/g‐C3N4 (Au/SO/CN) nanocomposites have been successfully synthesized and applied in the H2 evolution as photocatalysts, which exhibit superior photocatalytic activities and favorable stability without any cocatalyst under visible‐light irradiation. The amount‐optimized 2Au/6SO/CN nanocomposite capable of producing approximately 770 μmol g?1 h?1 H2 gas under λ > 400 nm light illumination far surpasses the H2 gas output of SO/CN (130 μmol g?1), Au/CN (112 μmol g?1 h?1), and CN (11 μmol g?1 h?1) as a contrast. In addition, the photocatalytic activity of 2Au/6SO/CN maintains unchanged for 5 runs in 5 h. The enhanced photoactivity for H2 evolution is attributed to the prominently promoted photogenerated charge separation via the excited electron transfer from plasmonic Au (≈520 nm) and CN (470 nm > λ > 400 nm) to SO, as indicated by the surface photovoltage spectra, photoelectrochemical I–V curves, electrochemical impedance spectra, examination of formed hydroxyl radicals, and photocurrent action spectra. Moreover, the Kelvin probe test indicates that the newly aligned conduction band of SO in the fabricated 2Au/6SO/CN is indispensable to assist developing a proper energy platform for the photocatalytic H2 evolution. This work distinctly provides a feasible strategy to synthesize highly efficient plasmonic‐assisted CN‐based photocatalysts utilized for solar fuel production. 相似文献
5.
Self‐Assembled BiFeO3‐ε‐Fe2O3 Vertical Heteroepitaxy for Visible Light Photoelectrochemistry 下载免费PDF全文
Le Thi Quynh Chien Nguyen Van Yugandhar Bitla Jhih‐Wei Chen Thi Hien Do Wen‐Yen Tzeng Sheng‐Chieh Liao Kai‐An Tsai Yi‐Chun Chen Chun‐Lin Wu Chih‐Huang Lai Chih‐Wei Luo Yung‐Jung Hsu Ying‐Hao Chu 《Liver Transplantation》2016,6(18)
Self‐assembled vertical heterostructure with a high interface‐to‐volume ratio offers tremendous opportunities to realize intriguing properties and advanced modulation of functionalities. Here, a heterostructure composed of two visible‐light photocatalysts, BiFeO3 (BFO) and ε‐Fe2O3 (ε‐FO), is designed to investigate its photoelectrochemical performance. The structural characterization of the BFO‐FO heterostructures confirms the phase separation with BFO nanopillars embedded in the ε‐FO matrix. The investigation of band structure of the heterojunction suggests the assistance of photoexcited carrier separation, leading to an enhanced photoelectrochemical performance. The insights into the charge separation are further revealed by means of ultrafast dynamics and electrochemical impedance spectroscopies. This work shows a delicate design of the self‐assembled vertical heteroepitaxy by taking advantage of the intimate contact between two phases that can lead to a tunable charge interaction, providing a new configuration for the optimization of photoelectrochemical cell. 相似文献
6.
In Situ Phase‐Induced Spatial Charge Separation in Core–Shell Oxynitride Nanocube Heterojunctions Realizing Robust Solar Water Splitting 下载免费PDF全文
Jungang Hou Yunzhen Wu Shuyan Cao Fei Liang Zheshuai Lin Zhanming Gao Licheng Sun 《Liver Transplantation》2017,7(17)
Efficient spatial charge separation is critical for solar energy conversion over solid photocatalysts. The development of efficient visible‐light photocatalysts has been of immense interest, but with limited success. Here, multiband core–shell oxynitride nanocube heterojunctions composed of a tantalum nitride (Ta3N5) core and nitrogen‐doped sodium tantalate (NaTaON) shell have been constructed via an in situ phase‐induced etching chemical strategy. The photocatalytic water splitting performance of sub‐20‐nm Ta3N5@NaTaON junctions exhibits an extraordinarily high photocatalytic activity toward oxygen and hydrogen evolution. Most importantly, the combined experimental results and theoretical calculations reveal that the strong interfacial Ta? O? N bonding connection as a touchstone among Ta3N5@NaTaON junctions provides a continuous charge transport pathway rather than a random charge accumulation. The prolonged photoexcited charge carrier lifetime and suitable band matching between the Ta3N5 core and NaTaON shell facilitate the separation of photoinduced electron–hole pairs, accounting for the highly efficient photocatalytic performance. This work establishes the use of (oxy)nitride heterojunctions as viable photocatalysts for the conversion of solar energy into fuels. 相似文献
7.
Ying‐Ying Han Xiu‐Li Lu Shang‐Feng Tang Xue‐Peng Yin Zhen‐Wei Wei Tong‐Bu Lu 《Liver Transplantation》2018,8(16)
The design and synthesis of efficient metal‐free photoelectrocatalysts for water splitting are of great significance, as nonmetal elements are generally earth abundant and environment friendly. As a typical metal‐free semiconductor, g‐C3N4 has received much attention in the field of photocatalytic water splitting. However, the poor photoinduced hole mobility of g‐C3N4 restrains its catalytic performance. Herein, for the first time, graphdiyne (GDY) is used to interact with g‐C3N4 to construct a metal‐free 2D/2D heterojunction of g‐C3N4/GDY as an efficient photoelectrocatalyst for water splitting. The g‐C3N4/GDY photocathode exhibits enhanced photocarriers separation due to excellent hole transfer nature of graphdiyne and the structure of 2D/2D heterojunction of g‐C3N4/GDY, realizing a sevenfold increase in electron life time (610 μs) compared to that of g‐C3N4 (88 μs), and a threefold increase in photocurrent density (?98 μA cm?2) compared to that of g‐C3N4 photocathode (?32 μA cm?2) at a potential of 0 V versus normal hydrogen electrode (NHE) in neutral aqueous solution. The photoelectrocatalytic performance can be further improved by fabricating Pt@g‐C3N4/GDY, which displays an photocurrent of ?133 μA cm?2 at a potential of 0 V versus NHE in neutral aqueous solution. This work provides a new strategy for the design of efficient metal‐free photoelectrocatalysts for water splitting. 相似文献
8.
Xiaojie She Jingjie Wu Hui Xu Jun Zhong Yan Wang Yanhua Song Kaiqi Nie Yang Liu Yingchao Yang Marco‐Tulio F. Rodrigues Robert Vajtai Jun Lou Daolin Du Huaming Li Pulickel M. Ajayan 《Liver Transplantation》2017,7(17)
Photocatalysis is the most promising method for achieving artificial photosynthesis, but a bottleneck is encountered in finding materials that could efficiently promote the water splitting reaction. The nontoxicity, low cost, and versatility of photocatalysts make them especially attractive for this application. This study demonstrates that small amounts of α‐Fe2O3 nanosheets can actively promote exfoliation of g‐C3N4, producing 2D hybrid that exhibits tight interfaces and an all‐solid‐state Z‐scheme junction. These nanostructured hybrids present a high H2 evolution rate >3 × 104 µmol g‐1 h‐1 and external quantum efficiency of 44.35% at λ = 420 nm, the highest value so far reported among the family of g‐C3N4 photocatalysts. Besides effectively suppressing the recombination of electron–hole pairs, this Z‐scheme junction also exhibits activity toward overall water splitting without any sacrificial donor. The proposed synthetic route for controlled production of 2D g‐C3N4‐based structures provides a scalable alternative toward the development of highly efficient and active photocatalysts. 相似文献
9.
Long‐Lived,Visible‐Light‐Excited Charge Carriers of TiO2/BiVO4 Nanocomposites and their Unexpected Photoactivity for Water Splitting 下载免费PDF全文
Mingzheng Xie Xuedong Fu Liqiang Jing Peng Luan Yujie Feng Honggang Fu 《Liver Transplantation》2014,4(5)
Different mole ratios of TiO2/BiVO4 nanocomposites with effective contacts have are fabricated by putting BiVO4 nanoparticles into the TiO2 sol, followed by thermal treatment at 450 °C. Based on the transient‐state surface photovoltage responses and the atmosphere‐controlled steady‐state surface photovoltage spectra, it is concluded that the photogenerated charge carriers in the TiO2/BiVO4 nanocomposite with a proper mole ratio (5%) display much longer lifetime and higher separation than those in the BiVO4 alone. This is responsible for the unexpected activity for photoelectrochemical oxidation of water, for photocatalytic production of H2, and for photocatalytic degradation of phenol as a model pollutant under visible irradiation. Moreover, it is suggested that the prolonged lifetime and increased separation of photogenerated charges in the fabricated TiO2/BiVO4 nanocomposite is attributed to the unusual spatial transfer of visible‐excited high‐energy electrons of BiVO4 to TiO2. This work will provide feasible routes to synthesize visible‐light responsive nanomaterials for efficient solar utilization. 相似文献
10.
Yangang Wang Tian Li Yonggang Yao Xi Li Xia Bai Chaochuang Yin Nicholas Williams Shifei Kang Lifeng Cui Liangbing Hu 《Liver Transplantation》2018,8(16)
Photocatalytic reduction of CO2 with H2O vapor is gaining increased interest because it is a promising “green chemistry” route for the direct conversion of CO2 to value‐added chemicals driven by solar energy. To increase the efficiency of photocatalytic conversion, most efforts are made by exploring various photocatalysts while little effort on advanced light management. For the first time, it is demonstrated that bio‐degradable transparent paper with excellent light diffusivity can effectively enhance the light utilization of photocatalytic reactions when attached on the device surface, and thus greatly increase the conversion efficiency. As a proof‐of‐concept, a graphitic carbon nitride (g‐C3N4) photocatalyst with transparent paper attached, exhibited 1.5 times higher photocatalytic activity than bare g‐C3N4 in the reduction of CO2 under visible light irradiation. The improved catalytic performance can be ascribed to the (1) refractive index matching and (2) enhanced light absorption via prolonged light traveling path in transparent paper, which decreases the light reflection at surface and traps the absorbed light inside, leading to an increased light absorption at the active layer of the device. The transparent paper with a controllable light management behavior has an unprecedented potential for applications in photocatalysis as a general method for improved light utilization. 相似文献
11.
Shangcong Sun Guoqiang Shen Jiawei Jiang Wenbo Mi Xianlong Liu Lun Pan Xiangwen Zhang Ji‐Jun Zou 《Liver Transplantation》2019,9(30)
Solar‐driven water splitting is in urgent need for sustainable energy research, for which accelerating oxygen evolution kinetics along with charge migration is the key issue. Herein, Mn3+ within π‐conjugated carbon nitride (C3N4) in form of Mn–N–C motifs is coordinated. The spin state (eg orbital filling) of Mn centers is regulated by controlling the bond strength of Mn–N. It is demonstrated that Mn serves as intrinsic oxygen evolution reaction (OER) site and the kinetics is dependent on its spin state with an optimized eg occupancy of ≈0.95. Specifically, the governing role of eg occupancy originates from the varied binding strength between Mn and OER intermediates. Benefiting from the rapid spin state‐mediated OER kinetics, as well as extended optical absorption (to 600 nm) and accelerated charge separation by intercalated metal‐to‐ligand state, Mn–C3N4 stoichiometrically splits pure water with H2 production rate up to 695.1 µmol g?1 h?1 under simulated sunlight irradiation (AM1.5), and achieves an apparent quantum efficiency of 4.0% at 420 nm, superior to most solid‐state based photocatalysts to date. This work for the first time correlates photocatalytic redox kinetics with the spin state of active sites, and suggests a nexus between photocatalysis and spin theory. 相似文献
12.
Single‐Crystalline Nanomesh Tantalum Nitride Photocatalyst with Improved Hydrogen‐Evolving Performance 下载免费PDF全文
Tantalum nitride (Ta3N5) with a suitable bandgap (≈2 eV) is regarded as one of the most promising photocatalysts for efficient solar energy harvesting and conversion. However, Ta3N5 suffers from low hydrogen production activity due to the low carrier mobility and fast carrier recombination. Thus, the design of Ta3N5 nanostructures to facilitate charge carrier transport and improve photocatalytic performance remains a challenge. This study reports a new type of ultrathin (≈2 nm) Ta3N5 nanomesh with high specific surface area (284.6 m2 g?1) and excellent crystallinity by an innovative bottom‐up graphene oxide templated strategy. The resulting Ta3N5 nanomeshes demonstrate drastically improved electron transport ability and prolonged lifetime of charge carriers, due to the nature of high surface area and excellent crystallinity. As a result, when used as photocatalysts, the Ta3N5 nanomeshes exhibit a greater than tenfold improvement in solar hydrogen production compared to bulk counterparts. This work provides an effective and generic strategy for designing 2D ultrathin nanomesh structures for nonlayered materials with improved catalytic activity. 相似文献
13.
Synthesis of Large Surface‐Area g‐C3N4 Comodified with MnOx and Au‐TiO2 as Efficient Visible‐Light Photocatalysts for Fuel Production 下载免费PDF全文
Fazal Raziq Liqun Sun Yuying Wang Xuliang Zhang Muhammad Humayun Sharafat Ali Linlu Bai Yang Qu Haitao Yu Liqiang Jing 《Liver Transplantation》2018,8(3)
Herein, this study successfully fabricates porous g‐C3N4‐based nanocomposites by decorating sheet‐like nanostructured MnOx and subsequently coupling Au‐modified nanocrystalline TiO2. It is clearly demonstrated that the as‐prepared amount‐optimized nanocomposite exhibits exceptional visible‐light photocatalytic activities for CO2 conversion to CH4 and for H2 evolution, respectively by ≈28‐time (140 µmol g?1 h?1) and ≈31‐time (313 µmol g?1 h?1) enhancement compared to the widely accepted outstanding g‐C3N4 prepared with urea as the raw material, along with the calculated quantum efficiencies of ≈4.92% and 2.78% at 420 nm wavelength. It is confirmed mainly based on the steady‐state surface photovoltage spectra, transient‐state surface photovoltage responses, fluorescence spectra related to the produced ?OH amount, and electrochemical reduction curves that the exceptional photoactivities are comprehensively attributed to the large surface area (85.5 m2 g?1) due to the porous structure, to the greatly enhanced charge separation and to the introduced catalytic functions to the carrier‐related redox reactions by decorating MnOx and coupling Au‐TiO2, respectively, to modulate holes and electrons. Moreover, it is suggested mainly based on the photocatalytic experiments of CO2 reduction with isotope 13CO2 and D2O that the produced ?CO2 and ?H as active radicals would be dominant to initiate the conversion of CO2 to CH4. 相似文献
14.
Bandgap Engineering of Organic Semiconductors for Highly Efficient Photocatalytic Water Splitting 下载免费PDF全文
Yiou Wang Fabrizio Silveri Mustafa K. Bayazit Qiushi Ruan Yaomin Li Jijia Xie C. Richard A. Catlow Junwang Tang 《Liver Transplantation》2018,8(24)
The bandgap engineering of semiconductors, in particular low‐cost organic/polymeric photocatalysts could directly influence their behavior in visible photon harvesting. However, an effective and rational pathway to stepwise change of the bandgap of an organic/polymeric photocatalyst is still very challenging. An efficient strategy is demonstrated to tailor the bandgap from 2.7 eV to 1.9 eV of organic photocatalysts by carefully manipulating the linker/terminal atoms in the chains via innovatively designed polymerization. These polymers work in a stable and efficient manner for both H2 and O2 evolution at ambient conditions (420 nm < λ < 710 nm), exhibiting up to 18 times higher hydrogen evolution rate (HER) than a reference photocatalyst g‐C3N4 and leading to high apparent quantum yields (AQYs) of 8.6%/2.5% at 420/500 nm, respectively. For the oxygen evolution rate (OER), the optimal polymer shows 19 times higher activity compared to g‐C3N4 with excellent AQYs of 4.3%/1.0% at 420/500 nm. Both theoretical modeling and spectroscopic results indicate that such remarkable enhancement is due to the increased light harvesting and improved charge separation. This strategy thus paves a novel avenue to fabricate highly efficient organic/polymeric photocatalysts with precisely tunable operation windows and enhanced charge separation. 相似文献
15.
Silver‐doped graphite carbon nitride nanosheets as fluorescent probe for the detection of curcumin 下载免费PDF全文
Haifen Yang Xuebing Li Xinxv Wang Wenfang Chen Wei Bian Martin M. F. Choi 《Luminescence》2018,33(6):1062-1069
Green fluorescent silver (Ag)‐doped graphite carbon nitride (Ag‐g‐C3N4) nanosheets have been fabricated by an ultrasonic exfoliating method. The fluorescence of the Ag‐g‐C3N4 nanosheets is quenched by curcumin. The fluorescence intensity decreases with the increase in the concentration of curcumin, indicating that the Ag‐g‐C3N4 nanosheets can function as a non‐toxic and facile fluorescence probe to detect curcumin. The fluorescence intensity of Ag‐g‐C3N4 nanosheets shows a linear relationship to curcumin in the concentration range 0.01–2.00 μM with a low detection limit of 38 nM. The fluorescence quenching process between curcumin and Ag‐g‐C3N4 nanosheets mainly is based on static quenching. The fluorescent probe has been successfully applied to analyse curcumin in human urine and serum samples with satisfactory results. 相似文献
16.
Ziyang Lu Qinghua Liang Bo Wang Ying Tao Yufeng Zhao Wei Lv Donghai Liu Chen Zhang Zhe Weng Jiachen Liang Huan Li Quan‐Hong Yang 《Liver Transplantation》2019,9(7)
Uncontrolled dendrites resulting from nonuniform lithium (Li) nucleation/growth and Li volume expansion during charging cause serious safety problems for Li anode‐based batteries. Here the coating of nickel foam with graphitic carbon nitride (g‐C3N4) to have a 3D current collector (g‐C3N4@Ni foam) for dendrite‐free Li metal anodes is reported. The lithiophilic g‐C3N4 coupled with the 3D framework is demonstrated to be highly effective for promoting the uniform deposition of Li and suppressing the formation of dendrites. Both density functional theory calculations and experimental studies indicate the formation of a micro‐electric field resulting from the tri‐s‐triazine units of g‐C3N4, which induces numerous Li nuclei during the initial nucleation stage, effectively guiding the following Li growth on the 3D Ni foam to be well distributed. Furthermore, the 3D porous framework is favorable for absorbing any volume change and stabilizing the solid–electrolyte interphase layer during repeated Li plating/stripping. As such, a Li metal anode based on the g‐C3N4@Ni foam has a remarkable electrochemical performance with a high Coulombic efficiency (98% retention after 300 cycles), an ultralong lifespan up to 900 h, as well as a low overpotential (<15 mV at 1.0 mA cm?2) at a Li deposition of 9.0 mA h cm?2. 相似文献
17.
Shuai Zhang Yunxuan Zhao Run Shi Chao Zhou Geoffrey I. N. Waterhouse Li‐Zhu Wu Chen‐Ho Tung Tierui Zhang 《Liver Transplantation》2020,10(8)
The photocatalytic reduction of nitrogen (N2) with water (H2O) as the reducing agent holds great promise as a sustainable future technology for the synthesis of ammonia (NH3). Herein, the effect of oxygen vacancies and electron‐rich Cuδ+ on the performance of zinc‐aluminium layered double hydroxide (ZnAl‐LDH) nanosheet photocatalysts for N2 reduction to NH3 under UV–vis excitation is systematically explored. Results show that a 0.5%‐ZnAl‐LDH nanosheet photocatalyst (containing 0.5 mol% Cu by metal basis) affords a remarkable NH3 production rate of 110 µmol g?1 h?1 and excellent stability in pure water. The X‐ray absorption spectroscopy, electron paramagnetic resonance, and density functional theory calculations reveal that Cu addition imparts oxygen vacancies and coordinatively unsaturated Cuδ+ (δ < 2) with electron‐rich property in the ZnAl‐LDH nanosheets, both of which readily contribute to efficient separation and transfer of photogenerated electrons and holes and promote N2 adsorption, thereby both activating N2 and facilitating its multielectrons reduction to NH3. 相似文献
18.
Surface‐Plasmon‐Assisted Photoelectrochemical Reduction of CO2 and NO3− on Nanostructured Silver Electrodes 下载免费PDF全文
Youngsang Kim Erin B. Creel Elizabeth R. Corson Bryan D. McCloskey Jeffrey J. Urban Robert Kostecki 《Liver Transplantation》2018,8(22)
Electrochemical reduction of carbon dioxide (CO2) typically suffers from low selectivity and poor reaction rates that necessitate high overpotentials, which impede its possible application for CO2 capture, sequestration, or carbon‐based fuel production. New strategies to address these issues include the utilization of photoexcited charge carriers to overcome activation barriers for reactions that produce desirable products. This study demonstrates surface‐plasmon‐enhanced photoelectrochemical reduction of CO2 and nitrate (NO3?) on silver nanostructured electrodes. The observed photocurrent likely originates from a resonant charge transfer between the photogenerated plasmonic hot electrons and the lowest unoccupied molecular orbital (MO) acceptor energy levels of adsorbed CO2, NO3?, or their reductive intermediates. The observed differences in the resonant effects at the Ag electrode with respect to electrode potential and photon energy for CO2 versus NO3? reduction suggest that plasmonic hot‐carriers interact selectively with specific MO acceptor energy levels of adsorbed surface species such as CO2, NO3?, or their reductive intermediates. This unique plasmon‐assisted charge generation and transfer mechanism can be used to increase yield, efficiency, and selectivity of various photoelectrochemical processes. 相似文献
19.
Huanhuan Li Huiqin Chen Yan Xue Yuting Zhang Mengjie Zhang Wenqi Yu Guangyue Bai Kelei Zhuo Yanping Zheng 《Liver Transplantation》2020,10(35)
The main challenge in developing foldable Li–S batteries (LSB) lies in developing an electrode that is ultraflexible, conductive, and catalytic for dissolved lithium polysulfides (LiPSs). In this paper, lightweight macromolecule graphitic carbon nitride (g‐C3N4) film and a conductive polymer (CP) of poly(3,4‐ethylenedioxythiophene) shell are introduced into flexible LSBs by compositing with carbon cloth (CC). In the designed hybrid of CP/g‐C3N4@CC, 2D g‐C3N4 is used in the form of an effective trapper and functions as a continuous catalytic layer for LiPSs via the formation of pyridinic‐N‐Li bonds. This is revealed by both experimental investigations and theoretical analysis. The sandwich‐like CC and CP simultaneously bring an omnidirectional conductive network for fast interfacial reaction kinetics. With these benefits, the self‐supported CP/g‐C3N4@CC forms a powerful interaction system to fully in situ “lock” LiPSs in the commercial CC matrix. Thus, a substantially enhanced electrochemical performance is obtained at a high sulfur loading (4.7 mg cm–2) even operating in a pouch cell. This work may provide a potential avenue for practical use of high‐performance LSBs toward flexible energy‐storage devices. 相似文献
20.
Graphene Layers‐Wrapped Fe/Fe5C2 Nanoparticles Supported on N‐doped Graphene Nanosheets for Highly Efficient Oxygen Reduction 下载免费PDF全文
Synthesis of highly efficient nonprecious metal electrocatalysts for the oxygen reduction reaction (ORR) superior to platinum (Pt) is still a big challenge. Herein, a new highly active ORR electrocatalyst is reported based on graphene layers‐wrapped Fe/Fe5C2 nanoparticles supported on N‐doped graphene nanosheets (GL‐Fe/Fe5C2/NG) through simply annealing a mixture of bulk graphitic carbon nitride (g‐C3N4) and ferrocene. An interesting exfoliation–denitrogen mechanism underlying the conversion of bulk g‐C3N4 into N‐doped graphene nanosheets is revealed. Owing to the high graphitic degree, optimum N‐doping level and sufficient active sites from the graphene layers‐wrapped Fe/Fe5C2 nanoparticles, the as‐prepared GL‐Fe/Fe5C2/NG electrocatalyst obtained at 800 °C exhibits outstanding ORR activity with a 20 mV more positive half‐wave potential than the commercial Pt/C catalyst in 0.1 m KOH solution and a comparable onset potential of 0.98 V. This makes GL‐Fe/Fe5C2/NG an outstanding electrocatalyst for ORR in alkaline solution. 相似文献