物理化学学报2023，Vol.39Issue(2)：1-7,7.DOI:10.3866/PKU.WHXB202205028
钴钒水滑石纳米片用于电催化尿素氧化
Cobalt-Vanadium Layered Double Hydroxides Nanosheets as High-Performance Electrocatalysts for Urea Oxidation Reaction
摘要
Abstract
Hydrogen is considered as a desirable clean energy source for supporting human life in the future.Electrochemical water splitting is a promising method for generating carbon-free hydrogen.However,the relatively high overpotential of anodic oxygen evolution reaction(OER)is the main obstacle hindering the widespread popularity of water electrocatalysis technology.Recently,urea oxidation reaction(UOR)has gained significant attention as a potential alternative to OER for hydrogen production since the equilibrium potential of UOR is 0.86 V lower than that of OER.Transition metal-based layered double hydroxides(TM-LDHs)have been explored as promising UOR electrocatalysts,with the advantages of diversified metal species,stable two-dimensional layered structure and exchangeability of interlayer anions.To date,most studies have focused on TM-LDHs of late transition metals(e.g.,Ni,Co,and Fe).In this work,by combining early and late transition metals,CoV-LDHs nanosheets were fabricated via a simple one-step coprecipitation method as high-performance UOR electrocatalysts.Additionally,cobalt hydroxide(Co(OH)2),with a similar lamellar structure,was synthesized via the same method.When compared with Co(OH)2,CoV-LDHs nanosheets exhibited better UOR performance owing to the following advantages:1)The nanosheet structure of the as-fabricated CoV-LDHs electrocatalyst exposed a high number of active sites for the electrocatalytic conversion of urea.2)The introduction of V enhanced the wettability of the CoV-LDHs electrocatalyst;thus,increasing its intrinsic electrocatalytic kinetics.3)The d-electron compensation effect between Co(3d74s2)and V(3d34s2)was conducive to promoting the adsorption of urea.Therefore,the CoV-LDHs electrocatalyst exhibited a low electrochemical potential(1.52 V vs.the reversible hydrogen electrode,RHE)to achieve a current density of 10 mA·cm-2 in 1 mol·L-1 of potassium hydroxide containing 0.33 mol·L-1 urea,which was 70 mV less than that of Co(OH)2.The Tafel slope value of the CoV-LDHs electrocatalyst(99.9 mV·dec-1)was lower than that of Co(OH)2(115.9 mV·dec-1),indicating faster UOR kinetics over the CoV-LDHs electrocatalyst.Furthermore,the CoV-LDHs electrocatalyst displayed high stability,with a negligible potential increase after a 10-h chronopotentiometry test by maintaining the current density of 10 mA·cm-2.In conclusion,the present work not only shows that the d-electron compensation effect between early and late transition metals could adjust the local electronic structure of TM-LDHs to improve the UOR efficiency,but also provides a feasible route to design dedicated nanostructured TM-LDHs as high-performance UOR electrocatalysts.关键词
尿素氧化/水滑石/纳米片/d-电子补偿/润湿性Key words
Urea oxidation/Layered double hydroxide/Nanosheet/d-Electron compensation/Wettability分类
化学化工引用本文复制引用
刘瑶钰,王宇辰,刘碧莹,Mahmoud Amer,严凯..钴钒水滑石纳米片用于电催化尿素氧化[J].物理化学学报,2023,39(2):1-7,7.基金项目
The project was supported by the National Natural Science Foundation of China(22078374),the National Key R&D Program of China(2020YFC1807600),the National Ten Thousand Talent Plan,the Key-Area Research and Development Program of Guangdong Province(2019B110209003),the Guangdong Basic and Applied Basic Research Foundation(2019B1515120058),and the Scientific and Technological Planning Project of Guangzhou(202206010145).国家自然科学基金(22078374),国家重点研发计划(2020YFC1807600),国家万人计划,广东省重点领域研究发展计划(2019B110209003),广东省基础与应用基础研究基金(2019B1515120058)和广州市科技计划项目(202206010145)资助 （22078374）
