Rapid Plasma Preparation of Cuo Nanowires for Efficient Ammonia Synthesis

Abstract

The conversion of nitrate into high-value ammonia (NH3) by electrochemical means can significantly reduce environmental pollution and alleviate the energy crisis. The development of easily prepared, high-performance electrocatalysts and understanding the origins of their catalytic activity are crucial. In this study, we rapidly prepared an electrocatalyst (P-CuO-10/CF) using plasma technology, subsequently employed under neutral and low nitrate concentration conditions for electrochemical ammonia synthesis. In situ Raman spectroscopy revealed that the as-prepared material underwent an in situ phase transformation to CuO/Cu, its actual active phase. The transformed CuO exists in an amorphous structure, which mitigates the direct adsorption of Cu with the intermediates, thus avoiding the passivation phenomenon. This heterogeneous structure demonstrated superior nitrate conversion performance, achieving an ammonia yield of 3.57 mg h-1 cm-2 at -0.6 V vs RHE and a Faradaic efficiency of 95.7%. This strategy expands the application scope of copper-based materials in electrocatalysis and highlights the promising uses of plasma-prepared materials for electrocatalytic nitrate reduction to generate NH3.

Keywords: CuO, plasma, Surface reconstruction, Electrocatalytic nitrate reduction, Ammonia production