d-Band center modulation in CuNi alloy/graphene oxide catalysts for enhanced electrocatalytic ammonia synthesis from nitrate

Abstract

Industrial ammonia (NH₃) production is predominantly achieved by the Haber–Bosch process, which consumes substantial energy and emits significant CO₂. The electrochemical nitrate reduction reaction (NO₃RR) presents a promising alternative to the Haber–Bosch process due to its environmentally benign nature. Developing highly active, selective, and stable electrocatalysts for the NO₃RR remains a focal point of contemporary research. In this work, the d-band center of the Cu₁Ni₁@GO catalyst was strategically modulated via an alloying approach, endowing it with balanced adsorption and desorption capabilities for reaction intermediates. This optimization resulted in exceptional performance, achieving an ammonia yield of 3.47 mg h⁻¹ cm⁻² and a Faraday efficiency (FE) of 85.2% at an overpotential of −0.5 V vs. RHE. Theoretical calculations confirmed the d-band center shift in Cu₁Ni₁@GO and its profound influence on intermediate adsorption dynamics and NO₃RR activity, offering crucial insights for the rational design of advanced alloy catalysts. By elucidating the synergistic effect in CuNi @GO composites, this study offers insights for designing efficient catalysts for nitrate reduction to ammonia, with promising applications in sustainable energy and environmental protection.