Origin of Enhanced Ammonia Synthesis on Ru-Co Catalysts Unraveled by Density Functional Theory

被引:33
作者
Banisalman, Mosab Jaser [1 ]
Kim, Min-Cheol [1 ]
Han, Sang Soo [1 ]
机构
[1] Korea Inst Sci & Technol KIST, Computat Sci Res Ctr, Seoul 02792, South Korea
基金
新加坡国家研究基金会;
关键词
ammonia synthesis; bimetallic catalysts; Ru-Co; density functional theory; microkinetic modeling; DECOMPOSITION; ADSORPTION; ALLOY; N-2; NI;
D O I
10.1021/acscatal.1c05023
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Bimetallic Ru-Co catalysts have been reported as promising NH3 production catalysts that are better than various Ru-X alloys, including RuFe and pure Ru, under mild conditions; however, a systematic understanding of their superior activity is still lacking. Here, we report a comprehensive theoretical study on NH3 synthesis of Ru-Co catalysts using density functional theory and microkinetic modeling. Indeed, the RuCo surface enables more facile N-2 dissociation than the Ru surface, which results from the manifested Co-induced spin symmetry breaking of Ru. We also investigated the surface phase diagram of RuCo(0001) with partial pressures of H-2 and N-2 gases and found that the most stable phase of the RuCo surface consists of a fraction of both N and H atoms under experimental Haber-Bosch pressure conditions; however, NH3 can be readily produced on the surfaces without severe surface poisoning issues. Furthermore, this study shows that the spin-symmetry breaking of nonmagnetic surfaces can enhance the catalytic activity for NH3 synthesis, which provides an alternative strategy to catalyst design.
引用
收藏
页码:1090 / 1097
页数:8
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