Lu Ke, Xia Fan, Li Bomin, Liu Yuzi, Abdul Razak Iddrisu B, Gao Siyuan, Kaelin Jacob, Brown Dennis E, Cheng Yingwen
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States.
Center of Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States.
ACS Nano. 2021 Oct 26;15(10):16887-16895. doi: 10.1021/acsnano.1c07771. Epub 2021 Oct 6.
Electrochemical hydrogenation of N under ambient conditions is attractive for sustainable and distributable NH production but is limited by the lack of selective electrocatalysts. Herein, we describe active site motifs based on the Chevrel phase chalcogenide FeMoS that exhibit intrinsic activities for converting N to NH in aqueous electrolytes. Despite having a very low specific surface area of ∼2 m/g, this catalyst exhibited a Faradaic efficiency of 12.5% and an average rate of 70 μg h mg for NH production at -0.20 V vs RHE. Such activities were attributed to the unique composition and structure of FeMoS that provide synergistic multisites for activating and associating key reaction intermediates. Specifically, Fe/Mo sites assist adsorption and activation of N, whereas S sites stabilize hydrogen intermediate H* for N hydrogenation. Fe in FeMoS enhances binding of S with H* and thus inhibits the competing hydrogen evolution reaction. The spatial geometry of Fe, Mo, and S sites in FeMoS promotes conversion of N-H* association intermediates, reaching a turnover frequency of ∼0.23 s for NH production.
在环境条件下对氮气进行电化学氢化反应对于可持续且可分布式的氨生产具有吸引力，但受到缺乏选择性电催化剂的限制。在此，我们描述了基于 Chevrel 相硫族化物 FeMoS 的活性位点基序，其在水性电解质中展现出将氮气转化为氨的固有活性。尽管该催化剂的比表面积非常低，约为 2 m²/g，但在相对于可逆氢电极（RHE）为 -0.20 V 的电位下，该催化剂对氨生产的法拉第效率为 12.5%，平均产率为 70 μg h⁻¹ mg⁻¹。这些活性归因于 FeMoS 的独特组成和结构，其为活化和关联关键反应中间体提供了协同多位点。具体而言，Fe/Mo 位点有助于氮气的吸附和活化，而 S 位点稳定氢中间体 H以用于氮气氢化反应。FeMoS 中的 Fe 增强了 S 与 H的结合，从而抑制了竞争性析氢反应。FeMoS 中 Fe、Mo 和 S 位点的空间几何结构促进了 N-H*缔合中间体的转化，氨生产的周转频率达到约 0.23 s⁻¹。
