Coupling Cu with Au for enhanced electrocatalytic activity of nitrogen reduction reaction†
The electrochemical nitrogen reduction reaction (NRR) under ambient conditions is currently attracting intense attention, but it still remains a great challenge to develop highly selective and active NRR electrocatalysts. Inspired by the intrinsic NRR activity of Au, we systematically studied the synergistic enhanced effect of incorporating other transition metals into Au on its NRR activity. A general strategy was used to synthesize a series of Au-based bimetallic nanocatalysts (AuCu, AuAg, AuPd and AuRu), and the NRR catalytic performance of the as-obtained electrocatalysts was investigated in detail. The experimental results indicate that the positive effect of Cu on NRR was the most remarkable in comparison with that of Ag, Ru and Pd, which can be ascribed to the synergy of the Au and Cu components via modulating the electronic structure and further changing the binding affinity of adsorbed N atoms on the catalyst. Finally, the optimized nanocatalyst with the atom ratio of Au1Cu1 achieved the highest faradaic efficiency (54.96%) and ammonia yield rate (154.91 μg h−1 mgcat−1) at −0.2 V vs. RHE, exceeding those of the previously reported Au nanocatalysts.