催化学报 ›› 2023, Vol. 52: 252-262.DOI: 10.1016/S1872-2067(23)64501-2

• 论文 • 上一篇    下一篇

MXene负载3d金属单原子高效氮还原电催化剂的理论筛选

胡金念a, 田玲婵a, 王海燕a, 孟洋a, 梁锦霞a,*(), 朱纯a,b,*(), 李隽b,c,*()   

  1. a贵州大学化学与化工学院, 贵州贵阳550025
    b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
    c清华大学化学系, 稀土新材料教育部工程研究中心, 北京100084
  • 收稿日期:2023-06-16 接受日期:2023-08-10 出版日期:2023-09-18 发布日期:2023-09-25
  • 通讯作者: *电子信箱: liangjx2009@163.com (梁锦霞),czhu2014@163.com (朱纯),junli@tsinghua.edu.cn (李隽).
  • 基金资助:
    国家重点研发计划项目(2022YFA1503900);国家重点研发计划项目(2022YFA1503000);国家自然科学基金(22033005);国家自然科学基金(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)

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

Jin-Nian Hua, Ling-Chan Tiana, Haiyan Wanga, Yang Menga, Jin-Xia Lianga,*(), Chun Zhua,b,*(), Jun Lib,c,*()   

  1. aSchool of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, Guizhou, China
    bDepartment of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
    cDepartment of Chemistry and Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education, Tsinghua University, Beijing 100084, China
  • Received:2023-06-16 Accepted:2023-08-10 Online:2023-09-18 Published:2023-09-25
  • Contact: *E-mail: liangjx2009@163.com (J. Liang),czhu2014@163.com (C. Zhu),junli@tsinghua.edu.cn (J. Li).
  • Supported by:
    National Key R&D Project(2022YFA1503900);National Key R&D Project(2022YFA1503000);National Natural Science Foundation of China(22033005);National Natural Science Foundation of China(21963005);Natural Science Special Foundation of Guizhou University(202140);Guangdong Provincial Key Laboratory of Catalysis(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 °C)和高压(约10‒15 MPa)等苛刻条件, 从而导致大量的CO2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Ti2CO2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M1@Ti2CO2)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N2还原生成NH3 (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V1@Ti2CO2, 该催化剂对NRR具有较好的电催化性能. 结果表明, V1@Ti2CO2不仅具有较强的N2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V1@Ti2CO2上活化的N2分子电催化加氢, 最优的混合路径中*NH*N, *NH2*N, *N, *NH, *NH2和*NH3中间体逐渐生成, 直至两个NH3分子从单原子催化剂V1@Ti2CO2表面脱附. 在最优的混合路径中, 电势决定步骤是*NH2 → *NH3, 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V1@Ti2CO2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V1@Ti2CO2对HER表现出较强的抑制能力. V1@Ti2CO2较好的NRR催化活性主要归因于催化剂负载的金属单原子和载体之间形成了强的金属-载体共价相互作用(CMSI), 从而使V的单原子催化剂具有高度稳定性且V原子具有较好的N2吸附和活化能力. 此外, Bader电荷分析、电子密度差分、PDOS以及ICOHP分析结果表明, 嵌入的V单原子作为电荷传递的通道促进电子在载体和吸附质之间转移, 从而提高了单原子催化剂V1@Ti2CO2对NRR的电催化性能. 进一步研究了溶剂化效应和不同pH(pH = 0, 3, 5, 7, 9, 11和14)条件对单原子催化剂V1@Ti2CO2电催化性能的影响, 发现水溶剂对V1@Ti2CO2电催化性能有一定的促进作用, 并且在pH = 0的酸性条件下V1@Ti2CO2电催化活性最好.

综上, 本研究从理论上预测得到一种对NRR具有高的电催化活性和选择性的MXene负载的单原子催化剂V1@Ti2CO2, 在溶剂以及酸性条件下, 有利于提高V1@Ti2CO2的NRR电催化活性. 本文为MXene负载金属单原子或单团簇的计算筛选实现相对温和条件下的NRR转化提供了一定的理论参考.

关键词: 单原子催化剂, 密度泛函理论, N2还原, 缺陷Ti2CO2, 电催化

Abstract:

Single-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 Ti2CO2 (denoted as M1@Ti2CO2). A highly stable V1@Ti2CO2 catalyst has been found to show excellent catalytic performance for N2 reduction reaction to produce NH3 after screening the 3d transition metals. The results show that V1@Ti2CO2 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@Ti2CO2 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@Ti2CO2 is a potentially promising 2D material for building robust electrocatalyst for NRR.

Key words: Single-atom catalyst, Density functional theory, N2 reduction, Defective Ti2CO2, Electrocatalysis