Modulation of Reactive Hydrogen Adsorbed on Dual-Active Site NiMoO₄ Nanocubes for Reduction of Nitrate to Ammonia

Development of highly active and selective electrocatalysts for the reduction of nitrate (NO₃^–) to ammonia is critical for the production of green ammonia. Herein, we designed and synthesized NiMoO₄ nanocubes as an efficient electrocatalyst for nitrate reduction using deep eutectic solvents (DESs) as synthesis media. By constructing Mo and Ni dual-active sites, Mo facilitates NO₃^– adsorption/association, and Ni acts as an active hydrogen (*H) donating center. The amount and destination of *H can be regulated, which can effectively enhance the activity of the NO₃^– reduction to NH₃ reaction (NO₃^–RR). The optimized sample possessed excellent NO₃^–RR activity. An NH₃–N selectivity of up to 96.94% and a Faraday efficiency of up to 96.13% can be achieved at −0.4 V in a neutral solution. The catalytic NO₃^–RR mechanism was also investigated by density functional theory (DFT) calculations. This dual-active site electrocatalyst provides an alternative idea for the synthesis and application of high-performance NO₃^–RR catalysts.