Constructing Ru single-atomic sites through potential-induced self-reconstruction to accelerate electrocatalytic nitrate reduction for ammonia production

Abstract

Conversion of NO3−-to-NH3 via the electrocatalytic nitrate reduction reaction (NO3-RR) is an emerging strategy for ammonia production and storage of “green hydrogen”, but is limited by the dissatisfactory activity and selectivity. In this study, we discovered that cobalt carbonate hydroxide (Co2(OH)2CO3) underwent a potential-induced self-reconstruction to cobalt hydroxide (Co(OH)2) during NO3-RR. The incorporation of Ru into Co2(OH)2CO3 expedited the aforementioned self-reconstruction process and resulted in the formation of Ru single-atomic sites (Ru SASs) anchored on Co(OH)2 nanosheets. This structure is reported as a highly efficient electrocatalyst for NO3−-to-NH3 conversion and exhibits exceptional electrochemical performance in zinc-NO3− batteries. Theoretical analysis revealed that the conversion of NO3−-to-NH3 occurred on Ru SASs through an N-end pathway with *NO as a characteristic intermediate. Furthermore, Ru SASs facilitated the thermodynamic-determining step of *NH2-to-*NH3, thus promoting the overall NO3−-to-NH3 conversion process.