Enhancement of Nitrate‐to‐Ammonia Over La(OH)3@CuCo Alloy Heterostructures via the Integration of Interface Engineering and Co Alloying

Abstract Cu‐based catalysts have shown promising results for the electrocatalytic nitrate reduction reaction (NO 3 RR) owing to their favorable ability to bind and activate NO 3 ⁻ , whereas the improvement in the catalytic NO 3 RR performance for NH 3 production is significantly limited by the strong adsorption of *NO 2 , which hinders the subsequent hydrogenation steps. Herein, a facile in situ exsolution strategy is proposed to prepare a series of La(OH) 3 @CuCo alloy heterostructures. The optimal La(OH) 3 /CuCo alloy heterostructures exhibit better catalytic NO 3 RR performance than La(OH) 3 /Cu under neutral condition, with high NH 3 yield rate of 8.80 mg h −1 mg cat −1 and Faradaic efficiency of 76.6% at −0.9 V. Ex situ x‐ray photoelectron spectroscopy and in situ electrochemical Fourier transform infrared spectroscopy in combination with theoretical calculation results have demonstrated that alloying of Cu with Co and heterostructure construction with La(OH) 3 can effectively modulate the electronic structure of Cu and optimize the adsorption strength of the reaction intermediates during the NO 3 RR process, promote the hydrogenation of *NO to form *NOH and the desorption of *NH 3 on the catalyst surface, which ultimately results in the enhanced NO 3 RR performance.