One-stone-for-two-birds strategy to achieve effective electrochemical nitrate reduction towards ammonia synthesis with Ru doped cobalt tungstate

Electrochemical nitrate reduction reaction (eNO3RR) 3 RR) offers a promising method for transforming nitrate pollutants into valuable ammonia (NH3). 3 ). Nevertheless, the sluggish kinetics of multiple reaction processes hinder NO3-conversion 3 - conversion efficiency and NH3 3 selectivity. In this study, we reported a one-stone-for-two-birds strategy where Ru-doped cobalt tungstate (Ru/CoWO4) 4 ) nanoparticles were synthesized via a one-pot solvothermal method, for regulating the efficiency and selectivity of eNO3RR 3 RR towards NH3 3 synthesis. The Ru/CoWO4 4 catalyst exhibits a high NH3 3 yield of 27.01mg/h mg cat-1 and a significant faradaic efficiency of 95.94 % at-0.7 V vs the reversible hydrogen electrode under basic condition. Notably, Ru/CoWO4 4 displays exceptional structural stability and electrochemical durability. Additionally, under varying anions in actual environment, Ru/CoWO4 4 maintains its catalytic activity without impeding eNO3RR. 3 RR. Density functional theory (DFT) calculations indicate that the incorporation of Ru decreases the surface charge, enhances the adsorption energy of nitrate on the catalyst surface, and reduces the Coulomb repulsion between the Ru atom and H+, + , which collectively improving the catalytic performance. Additionally, electron paramagnetic resonance tests reveals that the active hydrogen (Hads) ads ) produced from water electrolysis enhances the interaction with nitrogen-containing intermediates from eNO3RR, 3 RR, thereby suppressing the hydrogen evolution reaction and improving catalytic efficiency. This study provides a simple method for fabricating highly effective catalysts for the conversion of nitrate to valuable NH3. 3 .