Insights into Electrocatalytic Nitrate Reduction to Ammonia via Cu-Based Bimetallic Catalysts
Jing Zhao, Lijuan Liu, Ya Yang, Dan Liŭ, Xiaobo Peng, Shijing Liang, Lilong Jiang
Abstract
Cu-based bimetallic catalysts have been studied in the electrocatalytic nitrate (NO 3 – ) reduction reaction (NO 3 – RR) for a long time. However, few studies have focused on horizontal comparison of CuNi, CuCo, and CuFe (abbreviated as CuM) bimetallic catalysts in electrocatalytic NO 3 – RR for ammonia synthesis. Herein, we prepare the three series of Cu-based bimetallic catalysts, with different atom ratios of Cu/M (Cu/M = 7/3, 5/5, or 3/7) and ordered mesoporous carbon (OMC) as support (denoted as CuM/OMC). The characterization results reveal that the metallic particles of Cu and M components possess an intimate relationship on the CuM/OMC catalysts. The electrocatalytic NO 3 – RR performance uncovers that the optimal NH 3 yield rates of CuM/OMC catalysts at −0.8 V (vs reversible hydrogen electrode (RHE)) follow this order: Cu 5 Fe 5 /OMC > Cu 5 Co 5 /OMC > Cu 7 Ni 3 /OMC > Cu/OMC > Fe/OMC > Co/OMC > Ni/OMC > OMC. The bimetallic CuM/OMC catalysts exhibit higher NH 3 yield rates than the monometallic catalysts. This is attributed to strong synergistic effects between the Cu and M components. We expect that these insights can stimulate new developments of bimetallic catalysts in electrocatalysis.