In Situ Reconstructed Cu/Cu ₂₊₁ O/ZnO Inverse Opals Accelerate Electrocatalytic Nitrate Reduction Kinetics for High Power Zn‐NO ₃ ⁻ Battery

Abstract

Abstract The electroreduction of NO 3 − to NH 3 (NO 3 RR) using renewable energy presents a promising strategy to mitigate environmental pollution and produce high‐value chemicals. However, the practical application of NO 3 RR is hindered by limited active sites and sluggish reaction kinetics, stemming from the complex eight‐electron process. Herein, a novel Cu/Cu 2+1 O/ZnO‐2.5 inverse opals (CCZ‐IOs‐2.5) catalyst featuring a 3D porous network is designed, which provides abundant active sites and an optimized electronic structure to accelerate the NO 3 RR kinetics for efficient NH 3 production. Experimental and theoretical calculations reveal that the introduction of ZnO facilitates electron transfer to Cu active sites, increasing charge density and lowering the reaction energy barrier of the rate‐determining step (*NO to *NOH). As a result, CCZ‐IOs‐2.5 exhibits a notable enhancement in NH 3 yield (from 0.255 to 0.313 mmol h −1 cm −2 ) and Faradaic efficiency (from 85.7% to 95.5%) compared to the Cu/Cu 2+1 O catalyst. Thanks to its excellent NO 3 RR activity, the Zn‐NO 3 − battery with the CCZ‐IOs‐2.5 cathode achieves a max power density of 11.93 mW cm −2 . This study adopts a multi‐dimensional strategy encompassing morphology regulation, electronic structure optimization, and surface/interface engineering, offering new insights into efficient electrocatalyst development and realizing integrated NH 3 synthesis and energy output in a Zn‐NO 3 − battery.