Electrocatalytic reduction of nitrate to ammonia on CoMoO4 microspheres: A comparative study with Co3O4

Electrocatalytic nitrate reduction, as an emerging sustainable process for ammonia production, has garnered significant attention in recent years. In this study, mixed metal oxides CoMoO 4 microspheres was obtained by adding Mo 5+ to the preparation process of Co 3 O 4 . The obtained CoMoO 4 can effectively convert NO 3 – to NH 3 in neutral electrolytes (with a yield of up to 1481.49 μg h −1 mg -1 cat and a Faraday efficiency (FE) of 91.17 %), much better than Co 3 O 4 (with a yield of 785.56 μg h −1 mg -1 cat and a FE of 81.3 %). Subsequent characterization showed that compared to Co 3 O 4 , owing to the introduction of Mo, CoMoO 4 could increase production as well as consumption of *H, and showed enhanced adsorption capacity for reactants and intermediates. More interestingly, multiple characterizations and theoretical computations confirm that after adsorption key *NO intermediates on each catalyst, the change in electron aggregation position led to a different subsequent reaction pathway from *NO→*NOH→*N of Co 3 O 4 to *NO→*NHO of CoMoO 4 , the latter exhibits a lower reaction energy barrier, better facilitating the hydrogenation of *NO and ultimately improving NH 3 yield and selectivity.