Insights into the Origin of Activity Enhancement via Tuning Electronic Structure of CuO towards Electrocatalytic Ammonia Synthesis.

The insight of the activity phase and reaction mechanism is vital for developing high-performance ammonia synthesis electrocatalysts. In this study, the origin of the electronic-dependent activity for the model CuO catalyst toward ammonia electrosynthesis with nitrate was probed. The modulation of the electronic state and oxygen vacancy content of CuO was realized by doping with halogen elements (Cl, Br, I). The electrocatalytic experiments showed that the activity of the ammonia production depends strongly on the electronic states in CuO. With increased electronic state defects in CuO, the ammonia synthesis performance increased first and then decreased. The CuO/Br with electronic defects in the middle showed the highest ammonia yield of 11.4 g h g at -1.0 V (vs. RHE), indicating that the pattern of change in optimal ammonia activity is consistent with the phenomenon of volcano curves in reaction chemistry. This work highlights a promising route for designing NORR to NH catalysts.