Optimizing\nNitrate Reduction to Ammonia via Modulating\nAdsorption–Desorption Dynamics with High-Entropy CuNiCoZnMn\nAlloy Catalysts

NO<sub>3</sub>RR synthesis of ammonia is a complex eight-electron\nreaction involving multiple steps and intermediates, in which NO<sub>3</sub><sup>–</sup> adsorption and NH<sub>3</sub> desorption\nare crucial. The Cu-based high entropy quinary alloy catalyst has\ngood surface adsorption and desorption ability for the reduction of\nnitric acid to ammonia. Here, the catalytic sites were coordinated\nby constructing CuNiCoZnMn alloys to adjust the electronic structure\nof the catalytic sites to facilitate the reaction of the substrate\nand thus optimize the whole reaction path. Based on the ternary alloy\nCuNiCo, the introduction of the Zn element continues to reduce the\ndesorption energy barrier, and the introduction of the Mn element\ncontinues to enhance the initial adsorption energy so that the target\nproduct can be quickly held and released to accelerate the production\nof ammonia. The NH<sub>3</sub> yield and Faraday efficiency obtained\nfor the quinary CuNiCoZnMn alloy catalyst reached 723.7 μmol\nh<sup>–1</sup> cm<sup>–2</sup> and 96.6%, respectively,\nat −0.35 V vs RHE potential. The density functional theory\ncalculations showed that the quinary CuNiCoZnMn alloy (NO<sub>3</sub><sup>–</sup> to *NO<sub>3</sub><sup>–</sup>) initial\nadsorption-free energy change and (*NH<sub>3</sub> to NH<sub>3</sub>) NH<sub>3</sub> desorption-free energy change are −2.50,\n0.072 eV, respectively, which are significantly better than those\nof the ternary CuNiC and quaternary CuNiCoZn of −2.02, 0.544\neV and −1.97, 0.217 eV.