非金属掺杂石墨烯异核双原子催化剂氮还原特性研究  

Theoretical insights into heteronuclear dual metals on non‐metal doped graphene for nitrogen reduction reaction

作　　者：张季 俞爱民 孙成华 Ji Zhang;Aimin Yu;Chenghua Sun(Department of Electronical Engineering,Tongling University,Tongling 244061,Anhui,China;Department of Chemistry and Biotechnology,Swinburne University of Technology,Hawthorn,VIC 3122,Australia)

机构地区：[1]铜陵学院电气工程学院,安徽铜陵244061 [2]斯威本科技大学化学与生物技术系,澳大利亚

出　　处：《Chinese Journal of Catalysis》2023年第9期263-270,共8页催化学报（英文）

摘　　要：氨是化肥、涂料等领域中重要的化工原料,是产量第二高的商用化学品.目前,90%以上的氨均来自Haber-Bosch法,该工艺需要高温高压,能耗高,且依赖化石燃料的使用,排放大量CO_(2),在倡导节能环保的新时代,该工艺面临严重的能耗及环保问题.电催化氮还原合成氨(e NRR)是一种在常温常压条件下,采用电能作为驱动,以水和大气中的氮作为原料的新型绿色环保的合成氨方法,有望替代传统合成氨工艺.在eNRR过程中,电催化剂的催化活性和选择性是提高电催化合成氨的关键.目前,单原子催化剂(SAC)因其高原子利用率、高选择性等优点,在氧还原反应(ORR)、二氧化碳还原反应(CO_(2)RR)等方面得到广泛研究,但其在eNRR反应中表现不佳,因为单个金属原子位不能贡献足够多的电荷来活化惰性极强的N≡N键.据此,本文利用第一性原理计算,通过高通量筛选,系统研究了以非金属掺杂石墨烯为基质,以异核金属原子为反应位的双原子催化剂的氮还原特性及其微观催化机理.本文以B,S,P和N四种非金属元素与Fe,Co,Mo,W和Ru五种金属元素随机组成的40种催化剂M1M2-X做为催化剂模型,根据两步筛选,得到FeMo-S,RuMo-B,RuMo-P,RuMo-S和Ru W-S五种双原子催化剂,表现出优良的氮还原特性.与现有研究相比,五种双原子催化剂不但具有高催化活性(过电位为:FeMo-S(–0.18 V),RuMo-B(–0.25 V),RuMo-P(–0.27 V),RuMo-S(–0.29 V)和RuW-S(–0.24 V)),较高的热力学稳定性,而且可以有效抑制析氢(HER)反应.为了进一步与相应的单原子催化剂做比较,将单个金属原子键合于非金属元素掺杂的石墨烯基质上,形成17种M-X单原子催化剂.在同样的筛选机制下,只有Mo-P催化剂具有好的催化活性,但与HER的竞争劣势使其无法成为良好的催化剂.非金属原子调制的异核双原子催化剂对氮还原表现出良好的催化特性有其本质的原因.对双原子催化剂的电子特�Electrochemical nitrogen reduction reaction (eNRR) is a promising strategy for sustainable ammoniaproduction. To achieve high yield and energy efficiency, single-atom dispersion on nitrogen-doped graphene nanosheets has been extensively explored as an electrocatalyst for eNRR.However, challenges remain owing to the high overpotentials arising from unitary active sites andunabundant ligands. In this study, heteronuclear dual-metal catalysts with different non-metalsdoped in a graphene frame were computationally designed. After a two-step scanning based ondensity functional theory calculations, five candidates, namely FeMo-S, RuMo-B, RuMo-P, RuMo-S,and RuW-S, were identified as promising catalysts with calculated onset potentials of –0.18, –0.25,–0.27, –0.29, and –0.24 V, respectively. These catalysts can also effectively suppress the competitivehydrogen evolution reaction during NRR. Such excellent catalytic performance origins from twosynergetic effects: (1) the cooperation of heteronuclear metals contribute to the electron transferfrom active sites to the anti-bonding orbitals of N2 molecules adsorbed on catalysts to effectivelyactivate N≡N bonds;(2) metal-ligands (non-metals) interactions moderate the binding strength ofintermediates to slab, which is one of reasons for low NRR onset potential and high NH3 selectivity.The present study provides a theoretical understanding of the NRR mechanism of dual-metal catalysts,offering useful guidance for the rational design of catalysts with high selectivity and activityfor NRR.

关 键 词：电催化 双原子催化剂 石墨烯 氮还原反应 第一性原理 

分 类 号：O64[理学—物理化学]