MXene负载3d金属单原子高效氮还原电催化剂的理论筛选  

Theoretical screening of single‐atom electrocatalysts of MXene‐supported 3d‐metals for efficient nitrogen reduction

作　　者：胡金念 田玲婵 王海燕[1] 孟洋 梁锦霞 朱纯[1,2] 李隽 Jin-Nian Hu;Ling-Chan Tian;Haiyan Wang;Yang Meng;Jin-Xia Liang;Chun Zhu;Jun Li(School of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,Guizhou,China;Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry,Southern University of Science and Technology,Shenzhen 518055,Guangdong,China;Department of Chemistry and Engineering Research Center of Advanced Rare‐Earth Materials of Ministry of Education,Tsinghua University,Beijing100084,China)

机构地区：[1]贵州大学化学与化工学院,贵州贵阳550025 [2]南方科技大学化学系,广东省催化化学重点实验室,广东深圳518055 [3]清华大学化学系,稀土新材料教育部工程研究中心,北京100084

出　　处：《Chinese Journal of Catalysis》2023年第9期252-262,共11页催化学报（英文）

基　　金：国家重点研发计划项目(2022YFA1503900,2022YFA1503000);国家自然科学基金(22033005,21963005);贵州大学自然科学专项基金(202140);广东省催化重点实验室(2020B121201002).

摘　　要：氨是现代农业和工业不可缺少的化工原料,传统的Haber-Bosch合成氨生产工艺需要高温(~400℃)和高压(约10-15MPa)等苛刻条件,从而导致大量的CO_(2)排放和全球年1%-2%的能源消耗.因此,开发低温/低压和环境友好的新型合成氨催化剂对于可持续发展是非常重要的.近年来,单原子催化剂(SAC)作为一类新型的环境友好的催化材料在能源有效利用和环境保护中发挥了重要作用.MXenes是一类新型过渡金属碳化物/氮化物/碳氮化物二维纳米材料,因其具有类金属的导电性、亲水性、良好的柔性、可调节的多原子类型和原子层厚度以及表面端基修饰等物理化学特性,是较好的负载单原子催化剂的载体.MXenes负载的金属单原子催化剂(SAC)因其具有高稳定性、独特的电子结构和最高的原子利用率而成为潜在的低成本、高效环保的合成氨电催化剂.本文基于密度泛函理论(DFT)计算,系统研究了Ti_(2)CO_(2)的Ti缺陷位点被3d过渡金属M(Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu和Zn)原子占据所形成的SAC(记为M_1@Ti_(2)CO_(2))的电子结构、稳定性及电子性质.通过对3d过渡金属的筛选,考虑了可能的N_(2)还原生成NH_(3)(NRR)的电催化反应机理,发现了一种具有高稳定性的单原子催化剂V_1@Ti_(2)CO_(2),该催化剂对NRR具有较好的电催化性能.结果表明,V_1@Ti_(2)CO_(2)不仅具有较强的N_(2)吸附和活化能力,而且具有较好的NRR催化活性和选择性.随着吸附在V_1@Ti_(2)CO_(2)上活化的N_(2)分子电催化加氢,最优的混合路径中*NH*N,*NH_(2)~*N,*N,*NH,*NH_(2)和*NH_(3)中间体逐渐生成,直至两个NH_(3)分子从单原子催化剂V_1@Ti_(2)CO_(2)表面脱附.在最优的混合路径中,电势决定步骤是*NH_(2)→*NH_(3),其催化NRR反应的极限电位仅为-0.20 V.相对于NRR的竞争反应析氢反应(HER),计算结果表明单原子催化剂V_1@Ti_(2)CO_(2)上HER反应的极限电位为-0.73 V,远高于NRR反应的-0.20 V,说明V_1@Ti_(2Single-atom catalysts(SACs)with metal atoms embedded in MXenes are potentially low-cost,highly efficient,and environment-friendly electrocatalysts for ammonia production due to their high stability,unique electronic structure,and the highest atom utilization.Here,density functional theory calculations are carried out to systematically investigate the geometries,stability,electronic properties of SACs with the 3d-transition metal M(Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn)atoms embedded in the Ti defect sites of Ti_(2)CO_(2)(denoted as M1@Ti_(2)CO_(2)).A highly stable V1@Ti_(2)CO_(2)catalyst has been found to show excellent catalytic performance for N2 reduction reaction to produce NH_(3)after screening the 3d transition metals.The results show that V1@Ti_(2)CO_(2)can not only strongly adsorb N2,but also exhibits an excellent Nitrogen reduction reaction(NRR)catalytic activity with a limiting potential of only−0.20 V and a high ability to suppress the competing hydrogen evolution reaction.The excellent NRR catalytic activity of V1@Ti_(2)CO_(2)is attributed to the strong covalent metal-support interaction that leads to superb N2 adsorption ability of V atom.Furthermore,the embedded V single atoms facilitate electron transfer,thus improving the catalytic performance for NRR.These results demonstrate that V1@Ti_(2)CO_(2)is a potentially promising 2D material for building robust electrocatalyst for NRR.

关 键 词：单原子催化剂 密度泛函理论 N_(2)还原 缺陷Ti_(2)CO_(2) 电催化 

分 类 号：O64[理学—物理化学]