Efficient Fe-N4 site activated by Te doping with polarity engineering for enhanced nitrate electroreduction reaction

Abstract

Enhancing the polarity of conventional metal-N₄ catalytic sites can effectively modulate the adsorption behavior of reaction intermediates, thereby improving electrocatalytic performance. Herein, the polarity of the Fe-N₄ active center was regulated by doping Te atoms in its vicinity, resulting in enhanced catalytic activity for nitrate reduction to ammonia (NH₃) (NRA). The NH₃ faradaic efficiency (FE) of Fe-N₄/Te-CN reaches up to 99.9%, which is greatly superior to that of the undoped Fe-N₄/CN (60%). Density functional theory (DFT) calculations indicate that Te doping polarizes the Fe-N₄ site and upshifts its d-band center, enabling spontaneous nitrate adsorption and lowering the barrier of the rate-determining step, thereby promoting electrocatalytic NRA.