Regulation of the electronic structure of perovskites to improve the electrocatalytic performance for the nitrogen-reduction reaction

Abstract

Ammonia has received widespread attention as an indispensable chemical for humans and a potential energy source for a future low-carbon society. To meet the urgent requirements for a high output of synthetic ammonia by the electrocatalytic nitrogen reduction reaction (ENRR), the design of robust catalysts has become particularly important. Adjusting the charge and spin configuration of catalysts is a novel and effective way to optimize the ENRR barrier. We found that, through doping Co atoms, there was a correlation between the effective spin magnetic moment of the Co-LNO (Co-doped LaNiO₃) catalyst and its catalytic performance for the ENRR. Uniquely, LaNi_0.995Co_0.005O_3−δ with a high spin configuration was endowed with an excellent ENRR performance, including a high ammonia yield rate of 14.57 μg h⁻¹ mg⁻¹, an outstanding faradaic efficiency of 26.44%, and a remarkable energy efficiency of 21.35% (−0.1 V vs. the reversible hydrogen electrode). According to density functional theory calculations, we infer that Co-LNO provides Co with catalytically active sites and the accompanying oxygen vacancies to adjust the electronic structure and promote N₂ adsorption and the first protonation to form *NNH.