Optimizing Nitrate Electroreduction\ntoward Nearly\n100% Ammonia Selectivity through Synergistic RuCu Catalysts and Integrated\nCoupled Anodic Reaction for High-Value Products

Copper-based catalysts have been\nwidely used in the field of the\nnitrate reduction reaction (NO<sub>3</sub>RR) to ammonia, demonstrating\nhigh nitrate reduction rates. However, their low selectivity for ammonia\nproduction poses significant limitations in practical applications.\nIn this study, we present that the incorporation of Ru into the Cu@Ni\nfoam can achieve nearly 100% selectivity for NH<sub>3</sub> and a\nhigh faradaic efficiency of 96.8% in the NO<sub>3</sub>RR. Ru not\nonly facilitates the generation of adsorbed hydrogen but also suppresses\nthe HER reaction. This can be attributed to the unique electron distribution\nexhibited by Ru atoms when surrounded by Cu, leading to a decreased\nelectron-accepting capability. Consequently, this reduction results\nin a diminished Lewis acidity and a decreased H* adsorption. Importantly,\nit was confirmed that the incorporation of Cu with Ru serves as “anchor”\nfor atomic H* generated from Ru, inhibiting HER and ensuring the availability\nof H* for subsequent ammonia production. The synergistic effect between\nRu and Cu enhanced the efficiency and selectivity of reduction of\nnitrate to NH<sub>3</sub>. Remarkably, substituting oxygen evolution\nreaction (OER) with a coupled anodic reaction for the oxidation of\nbenzyl alcohol to benzaldehyde can significantly accelerate the nitrate\nreduction rate by 1.7 times and achieves a 90% benzaldehyde conversion\nrate. This research not only introduces innovative strategies for\ndesigning high-performance ammonia-selective electrocatalysts but\nalso highlights the potential industrial applications for the synthesis\nof high-value products.