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71.
Alkaline water electrolysis despite having a variety of choices for anodic oxygen evolution reaction (OER) catalysts out of non-precious metals suffers significantly due to the poor kinetics of cathodic hydrogen evolution reaction (HER) even with the state-of-the-art Pt and equally active Ru. The Volmer-step (water dissociation (WD) coupled proton adsorption) of alkaline HER is mostly the rate-determining step (RDS) and costs most of the work required. In this review, recent developments in improving the HER kinetics of Pt and Ru with Volmer-step promotors and electronic structure modulators have been comprehensively analyzed and critically presented with the challenges and prospects. 相似文献
72.
Haiyang Cui Prof. Dr. Karl-Erich Jaeger Dr. Mehdi D. Davari Prof. Dr. Ulrich Schwaneberg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(8):2789-2797
The CompassR (computer-assisted recombination) rule enables, among beneficial substitutions, the identification of those that can be recombined in directed evolution. Herein, a recombination strategy is systematically investigated to minimize experimental efforts and maximize possible improvements. In total, 15 beneficial substitutions from Bacillus subtilis lipase A (BSLA), which improves resistance to the organic cosolvent 1,4-dioxane (DOX), were studied to compare two recombination strategies, the two-gene recombination process (2GenReP) and the in silico guided recombination process (InSiReP), employing CompassR. Remarkably, both strategies yielded a highly DOX-resistant variant, M4 (I12R/Y49R/E65H/N98R/K122E/L124K), with up to 14.6-fold improvement after screening of about 270 clones. M4 has a remarkably enhanced resistance in 60 % (v/v) acetone (6.0-fold), 30 % (v/v) ethanol (2.1-fold), and 60 % (v/v) methanol (2.4-fold) compared with wild-type BSLA. Molecular dynamics simulations revealed that attracting water molecules by charged surface substitutions is the main driver for increasing the DOX resistance of BSLA M4. Both strategies and obtained molecular knowledge can likely be used to improve the properties of other enzymes with a similar α/β-hydrolase fold. 相似文献
73.
Anna Rabe Julia Büker Dr. Soma Salamon Adarsh Koul Dr. Ulrich Hagemann Dr. Joachim Landers Dr. Klaus Friedel Ortega Dr. Baoxiang Peng Prof. Dr. Martin Muhler Prof. Dr. Heiko Wende Prof. Dr. Wolfgang Schuhmann Prof. Dr. Malte Behrens 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(68):17038-17048
By using the crystalline precursor decomposition approach and direct co-precipitation the composition and mesostructure of cobalt-based spinels can be controlled. A systematic substitution of cobalt with redox-active iron and redox-inactive magnesium and aluminum in a cobalt spinel with anisotropic particle morphology with a preferred 111 surface termination is presented, resulting in a substitution series including Co3O4, MgCo2O4, Co2FeO4, Co2AlO4 and CoFe2O4. The role of redox pairs in the spinels is investigated in chemical water oxidation by using ceric ammonium nitrate (CAN test), electrochemical oxygen evolution reaction (OER) and H2O2 decomposition. Studying the effect of dominant surface termination, isotropic Co3O4 and CoFe2O4 catalysts with more or less spherical particles are compared to their anisotropic analogues. For CAN-test and OER, Co3+ plays the major role for high activity. In H2O2 decomposition, Co2+ reveals itself to be of major importance. Redox active cations in the structure enhance the catalytic activity in all reactions. A benefit of a predominant 111 surface termination depends on the cobalt oxidation state in the as-prepared catalysts and the investigated reaction. 相似文献
74.
石墨相氮化碳(g?C3N4)由于具有对可见光吸收范围较窄和光生载流子分离效率低等缺陷,其光解水产氢活性较差。我们采用简单的一步热共聚法,以尿素和2,4,6?三氨基嘧啶(TAPD)混合物为前驱物,制备碳自掺杂纳米片(CNNS?x,x mg代表掺入TAPD的质量)。X射线衍射(XRD)、元素分析(EA)和X射线光电子能谱(XPS)等测试结果表明,来自TAPD的嘧啶环成功引入g?C3N4共轭体系中,使所得的CNNS?x具有较窄的带隙,较快的光生载流子迁移速率,从而提高其对可见光的吸收效率和光生载流子的分离效率。得益于此,CNNS?x在可见光照射下表现出较好的光解水产氢活性。特别是CNNS?30具有最佳光解水性能,其产氢速率可达57.6μmol·h-1,是g?C3N4纳米片(CNNS)的4倍。 相似文献
75.
Haodong Nie Kaiqiang Wei Yi Li Yan Liu Yajie Zhao Hui Huang Mingwang Shao Yang Liu Zhenhui Kang 《中国化学快报》2021,32(7):2283-2286
Overall water photo-splitting is a prospective ideal pathway to produce ultra-clean H_2 energy by semiconductors.However,the band structure of many semiconductors cannot satisfy the requirement of H_2 and O_2 production at the same time.Herein,we illustrate that carbon dots(CDs)/Bi_2 WO_6 photocatalyst with compensatory photo-electronic effect has enhanced activity for overall water photo-splitting without any sacrificial agent.In this complex photocatalytic system,the photo-potential provided by CDs makes the CDs/Bi_2 WO6(C-BWO) composite could satisfy the band structure conditions for overall water photo-splitting.The C-BWO composite(3 wt% CDs content) exhibits optimized hydrogen evolution(oxygen evolution) of 0.28 μmol/h(0.12 μmol/h) with an approximate 2:1(H_2:O_2) stoichiometry at normal pressure.We further employed the in-situ transient photovoltage(TPV) technique to study the photoelectron extraction and the interface charge transfer kinetics of this composite catalyst. 相似文献
76.
《中国化学快报》2021,32(9):2597-2616
Electrochemical overall water splitting is attracting a broad focus as a promising strategy for converting the electrical output of renewable resources into chemical fuels, specifically oxygen and hydrogen. However, the urgent challenge in water electrolysis is to search for low-cost, high-efficiency catalysts based on earth-abundant elements as an alternative to the high-cost but effective noble metal-based catalysts. The transition metal-based catalysts are more appealing than the noble metal catalysts because of its low cost, high performance and long stability. Some recent advances for the development in overall water splitting are reviewed in terms of transition metal-based oxides, carbides, phosphides, sulfides, and hybrids of their mixtures as hybrid bifunctional electrocatalysts. Concentrating on different catalytic mechanisms, recent advances in their structural design, controllable synthesis, mechanistic insight, and performance-enhancing strategies are proposed. The challenges and prospects for the future development of transition metal-based bifunctional electrocatalysts are also addressed. 相似文献
77.
《中国化学快报》2021,32(11):3579-3583
Surface oxidized iron-nickel nanorods coupling with reduced graphene architectures (FeNi-O-rGA) are successfully constructed via hydrothermal, freeze-drying, and thermal activation approaches. The hierarchical structure can provide lots of pathways for fast ion diffusion and charge transfer, and expose abundant catalytic sites. Meanwhile, the activity of FeNi-O-rGA is boosted by the optimized metal-oxygen bond strength in FeNi3 alloys. Partial oxidized FeNi nanorods are strongly coupled with rGA by the formation of metal-O-C bonds, which can impede the aggregation of FeNi3 alloys and increase the utilization of active sites. The special structure and partially oxidized FeNi nanorods for FeNi-O-rGA can result in excellent OER activity and catalytic stability. Only 215 mV of overpotential is required to drive the current density of 10 mA/cm2 as well as the Tafel slope of 50.9 mV/dec in 1 mol/L KOH. The change of surface chemistry of FeNi-O-rGA is confirmed by XPS after the OER test, which indicates the highly catalytic stability of FeNi-O-rGA due to the formation of intermediate metal oxyhydroxide. 相似文献
78.
Yupeng Xing Xiaoke Wang Shuhua Hao Xueli Zhang Xiao Wang Wenxuan Ma Gang Zhao Xijin Xu 《中国化学快报》2021,32(1):13-20
g-C3N4 have been widely used in the fields of photocatalytic hydrogen production,photocatalytic degradation of dyes and oxidative degradation of toxic gases due to their excellent performance.It has attracted extensive attention in recent years due to its highly efficient photocatalytic capacity of hydrogen generation,water oxidation,carbon dioxide reduction and degradation of organic pollutants.Because of the abundant carbon and nitrogen composition of the earth,large-scale production and industrial applications of this material are possible.The modification of this material makes its performance more excellent so that this new material can obtain a steady stream of vitality.These outstanding works have become important materials and milestones on the road to mankind's photocatalytic hydrogen production.This review will begin with the basic idea of designing,synthesizing and improving g-C3N4 based photocatalytic materials,and introduce the latest development of g-C3N4 photocatalysts in hydrogen production from four aspects of controlling the carbon/nitrogen ratio,morphology,element doping and heterojunction structure of g-C3N4 materials. 相似文献
79.
Yunqie Deng Linjing Yang Yakun Wang Lili Zeng Jiayuan Yu Bo Chen Xiaoli Zhang Weijia Zhou 《中国化学快报》2021,32(1):511-515
Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co2P HMs).The obtained Ru NCs/Co2P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm2 in 0.5 mol/L H2SO4 and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co2P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm2 in 0.5 mol/L H2SO4,which is below that of the commercial RuO2 electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm2 at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V). 相似文献
80.
《中国化学快报》2021,32(11):3613-3618
Spatial isolation of different functional sites at the nanoscale in multifunctional catalysts for steering reaction sequence and paths remains a major challenge. Herein, we reported the spatial separation of dual-site Au and RuO2 on the nanosurface of TiO2 (Au/TiO2/RuO2) through the strong metal-support interaction (SMSI) and the lattice matching (LM) for robust photocatalytic hydrogen evolution. The SMSI between Au and TiO2 induced the encapsulation of Au nanoparticles by an impermeable TiOx overlayer, which can function as a physical separation barrier to the permeation of the second precursor. The LM between RuO2 and rutile-TiO2 can increase the stability of RuO2/TiO2 interface and thus prevent the aggregation of dual-site Au and RuO2 in the calcination process of removing TiOx overlayer of Au. The photocatalytic hydrogen production is used as a model reaction to evaluate the performance of spatially separated dual-site Au/TiO2/RuO2 catalysts. The rate of hydrogen production of the Au/TiO2/RuO2 is as high as 84 μmol h−1 g−1 under solar light irradiation without sacrificial agents, which is 2.5 times higher than the reference Au/TiO2 and non-separated Au/RuO2/TiO2 samples. Systematic characterizations verify that the spatially separated dual-site Au and RuO2 on the nanosurface of TiO2 can effectively separate the photo-generated carriers and lower the height of the Schottky barrier, respectively, under UV and visible light irradiation. This study provides new inspiration for the precise construction of different sites in multifunctional catalysts. 相似文献