Multi-Site CuZn Alloy Boosts Nitrate Reduction to Ammonia via Optimized Intermediate Adsorption.

Electrocatalytic nitrate reduction reaction (NORR) is an effective way to solve nitrate pollution and a promising strategy for ammonia (NH) synthesis under ambient temperature and pressure. However, NORR is still hindered by the lack of efficient catalysts and an understanding of mechanisms that enhance the catalytic performance. In this study, we propose intermetallic alloying as a promising strategy to optimize the NORR reaction pathway by tuning the adsorption energies and configurations of intermediates, as demonstrated by density functional theory (DFT) calculations comparing NORR performance of Cu (111) and CuZn (110) surfaces. In CuZn alloy, the electron-donating property of Cu weakens the adsorption of NO (x = 1, 2, and 3) intermediates, whereas the electron-accepting property of Zn strengthens the binding of NOH intermediates, thus lowering the protonation reaction energy. Zn sites preferentially promote the removal of O species, whereas Cu sites dominate the protonation of N species. This synergistic effect enables CuZn (110) surface to successfully break the undesirable scaling relationship in traditional metal catalysts, resulting in excellent catalytic activity for NORR, with an ultra-low limiting potential of -0.28 V. This work provides valuable insights and theoretical guidance for NORR.