Optimized Intermediates Adsorption Configuration on Co‐Doped Fe₂P@NiP₂ Heterojunction Interface for Enhanced Electrocatalytic Nitrate‐To‐Ammonia Conversion

AbstractThe extraction of ammonia (NH3) through electrocatalytic nitrate reduction reaction (NO3−RR) represents a sustainable avenue in NH3 generation and utilization. However, the catalytic efficiency of the NO3−RR is hindered by the sluggish kinetics. This study first theoretically found that phosphide‐based heterostructure can alter the adsorption structure of intermediates in the nitrate‐to‐ammonia process, thereby achieving precise regulation of the energy barrier in the rate‐determining step. Based on theoretical design, a novel Co‐doped Fe2P@NiP2 heterojunction catalyst is successfully synthesized, which deliver a notable NH3 yield rate of 0.395 mmol h−1 cm−2 at −0.7 V versus RHE, as well as a remarkable ammonia Faraday efficiency of 97.2% at −0.6 V versus RHE. Experimental and theoretical results further confirm that redistributing electrons and shifting the center of the d‐band upwards through interfacial doping modulate intermediates adsorption strength and inhibition of hydrogen evolution, leading to excellent performance in NO3−‐to‐NH3. Further integrating the Co‐Fe2P@NiP2 catalyst into a Zn‐nitrate battery exhibits a substantial voltage output of 1.49 V and a commendable power density of 13.2 mW cm−2. The heteroatom‐doped heterojunction strategy provides a versatile route for developing advanced catalysts, thereby broadening the horizons of electrocatalytic methodologies for nitrate reduction and ammonia synthesis.