Regulating the Electrochemical Nitrate Reduction Performance with Controllable Distribution of Unconventional Phase Copper on Alloy Nanostructures
Yuecheng Xiong, Yunhao Wang, Mingzi Sun, Jing Chen, Jingwen Zhou, Fengkun Hao, Fu Liu, Pengyi Lu, Xiang Meng, Liang Guo, Yuqian Liu, Shibo Xi, Qinghua Zhang, Bolong Huang, Zhanxi Fan
Abstract
Abstract Electrochemical nitrate reduction reaction (NO 3 RR) is emerging as a promising strategy for nitrate removal and ammonia (NH 3 ) production using renewable electricity. Although great progresses have been achieved, the crystal phase effect of electrocatalysts on NO 3 RR remains rarely explored. Here, the epitaxial growth of unconventional 2H Cu on hexagonal close‐packed ( hcp ) IrNi template, resulting in the formation of three IrNiCu@Cu nanostructures, is reported. IrNiCu@Cu‐20 shows superior catalytic performance, with NH 3 Faradaic efficiency (FE) of 86% at −0.1 (vs reversible hydrogen electrode [RHE]) and NH 3 yield rate of 687.3 mmol g Cu −1 h −1 , far better than common face‐centered cubic Cu. In sharp contrast, IrNiCu@Cu‐30 and IrNiCu@Cu‐50 covered by hcp Cu shell display high selectivity toward nitrite (NO 2 − ), with NO 2 − FE above 60% at 0.1 (vs RHE). Theoretical calculations have demonstrated that the IrNiCu@Cu‐20 has the optimal electronic structures for NO 3 RR due to the highest d‐band center and strongest reaction trend with the lowest energy barriers. The high electroactivity of IrNiCu@Cu‐20 originates from the abundant low coordination of Cu sites on the surface, which guarantees the fast electron transfer to accelerate the intermediate conversions. This work provides a feasible tactic to regulate the product distribution of NO 3 RR by crystal phase engineering of electrocatalysts.