Pulsed Laser-Initiated Dual-Catalytic Interfaces for Directed Electroreduction of Nitrite to Ammonia

Abstract

Green and highly selective synthesis of ammonia (NH3) via electrochemical reduction reaction of toxic nitrite (NO2-RR) in a neutral electrolyte is a feasible solution for energy and environmental issues. Dual-nature electrocatalysts combining metal and metal-derived materials are crucial for enhancing the selectivity parameter and efficacy of this reaction. Here, Pd-, Pt-, Ru-, and Ir-decorated Co3(PO4)2 (CoPi) composites with a robust metal-support interaction are obtained via the one-pot pulsed laser ablation in liquid method. Among the designed composites, Ir-CoPi affords approximate to 100% Faradaic efficiency, mass balance, and selectivity toward NH3 product at sufficiently low potentials. Further, it affords the highest NH3 yield rate of 19.13 mg h-1 cm-2 with 78.1% removal of toxic NO2- with a rate constant kapp = 0.31 mm min-1 under -1.6 V versus Ag/AgCl. In situ experiments and theoretical investigations reveal the underlying mechanisms responsible for this outstanding performance of Ir-CoPi, which can be accredited to the generation of specific active sites on the Ir component. Insights derived from the evolving intermediate reactive species provide new opportunities for large-scale NH3 production through electrochemical techniques, density functional theory calculations, and the improvement of the corresponding industrial processes. This study uses pulsed laser ablation in liquid to synthesize Pd-, Pt-, Ru-, and Ir-CoPi composites for green, selective NH3 synthesis via electrochemical nitrite reduction. Ir-CoPi's effectiveness is highlighted, with experimental and theoretical insights supporting its role in reducing thermodynamic barriers, impacting sustainable NH3 production and environmental benefits.image (c) 2024 WILEY-VCH GmbH