[Abstract]

The electrochemical nitrate reduction reaction (NO3RR) is of significance in regards of environmentally friendly issue and green ammonia production. However, relatively low performance with a competitive hydrogen evolution reaction (HER) is a challenge to overcome for the NO3RR. In this study, oxygen vacancy-controlled copper oxide (CuO_x) catalysts through a plasma treatment were successfully prepared and supported on high surface area porous carbon that were co-doped with N, Se species for its enhanced electrochemical properties. The oxygen vacancy-increased CuO_x catalyst supported on the N,Se co-doped porous carbon (CuO_x-H/NSePC) exhibited the highest NO₃RR performance with faradaic efficiency (FE) of 87.2% and yield of 7.9 mg cm^-2 h^-1 for the ammonia production, representing significant enhancements of FE and ammonia yield as compared to the un-doped or the oxygen vacancy-decreased catalysts. This high performance should be attributed to a significant increase in the catalytic active sites with facilitated energetics from strategies of doping the catalytic materials and weakening the N-O bonding strength for the adsorption of NO₃^- ions on the modulated oxygen vacancies. Our results show a promise that co-doping of heteroatoms and regulating of oxygen vacancies can be key factors for the performance enhancement, suggesting new guidelines for effective catalyst design of NO₃RR.

DOI: 10.1002/smll.202403253

Link: https://onlinelibrary.wiley.com/doi/10.1002/smll.202403253