Abstract

Electrocatalytic conversion of nitrate to ammonia via the nitrate reduction reaction (NO 3RR) is a sustainable method for ammonia production with simultaneous electricity generation. The electrocatalytic NO 3RR is not only a versatile and scalable method but also a strategic option for next-generation electric vehicles. Herein, we report the development of palladium-decorated copper (Pd@Cu) composite microspheres via pulsed laser irradiation in liquid, and their application as electrocatalysts for the NO 3RR. The Pd@Cu composite electrocatalyst achieved a maximum NH 3 yield rate of 13100 µg h −1 cm −2 and a Faradaic efficiency of 92.5% at −0.4 V vs.

the reversible hydrogen electrode. In-depth analysis of the NO 3RR kinetics using in situ microRaman, ex situ XRD, and ex situ Fourier transform infrared spectroscopy revealed information on reaction intermediates and confirmed the excellent electrochemical stability of the Pd@Cu-3 composite electrocatalyst for the electrocatalytic NO 3RR, supported by density functional theory calculations. A Zn–nitrate battery assembled with a Pd@Cu-3 composite as the cathode and a zinc plate as the anode exhibits an open-circuit voltage of 1.33 V and an ultralong cycling stability of 100 h at 10 mA cm −2 . The high NH 3 yield rate and excellent stability of the Pd@Cu-3 composite demonstrate its potential for real-world applications.