Electroreduction of nitrate (NO3-) has emerged as a promising strategy for producing ammonia (NH3) at room temperature in recent years. However, the formation of less electron-consuming H2 byproduct seriously limits the conversion efficiency of NO3- to NH3. In this study, we identify that N-doped Co3O4 can effectively convert NO3- to NH3 with a high performance (NH3 yield rate: 7.18 ± 0.59 mg h‒1 cm‒2, Faradaic efficiency: 96.7 ± 0.88 %), which is significantly higher than that pure Co3O4 (NH3 yield rate: 4.95 ± 0.54 mg h‒1 cm‒2) and most reported Co-based catalysts (Table S1). Density function theory (DFT) calculations coupled with X-ray absorption near-edge structure (XANES) experiments reveal that N-doping in Co3O4 releases more positive charge on Co atom site due to charge compensation. This oxidized Co atom site enhances the adsorption of NO3- while weakening the adsorption of H+ through Coulombic interactions, thus improving NO3RR activity. Overall, our study not only provide efficient electrocatalyst to avoid the formation of H2 byproduct to facilitate the conversion of NO3- to NH3, and opens new avenues towards achieving green ammonia production by controlling Coulombic interactions.

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