Efficient electrocatalytic reduction of nitric oxide (NO) to ammonia (NH3) on metal-free B4@g-C3N4 nanosheet

• Electrocatalysis of NO to NH 3 has been studied on metal-free B 4 @g-C 3 N 4 . • NO exhibits strong adsorption on B 4 @g-C 3 N 4 in side-on and end-on modes. • Findings reveal that the B 4 @g-C 3 N 4 nanosheet can effectively reduce NO to NH 3 . • B 4 @g-C 3 N 4 shows a remarkably low limiting potential ( U L ) of −0.29 V in gas phase. • Solvent and charge effects further decrease the U L value for NORR. The combustion of fossil fuels releases substantial amounts of nitric oxide (NO), posing serious environmental and health risks. Addressing NO pollution effectively is, therefore, a pressing need. Conversion of NO into valuable chemicals is an appealing strategy with dual benefits, including waste utilization and sustainable energy transformation. In this study, we investigate the metal-free electrocatalytic reduction of NO (NORR) to NH 3 on a B 4 atomic cluster supported by a g-C 3 N 4 nanosheet (B 4 @g-C 3 N 4 ) using density functional theory (DFT). Our findings reveal that NO is efficiently activated on the B 4 @g-C 3 N 4 catalyst, favoring side-on and N end-on adsorption configurations. Significant electron transfer and strong adsorption energies confirm the chemisorption of NO. The NORR exhibits an impressively low limiting potential ( U L ) of −0.29 V in the gas phase, which decreases further under solvent effects and varying charge states (−2e - , −1e - , +1e - , +2e - ). Additionally, the high negative U L values for competing side reactions such as H 2 (−0.42 V), N 2 (−0.29 V), and N 2 O (−0.72 V) underscore the selectivity of B 4 @g-C 3 N 4 for ammonia synthesis. These results highlight the promising potential of B 4 @g-C 3 N 4 nanosheets for eco-friendly ammonia production from NO, providing a theoretical basis for future experimental efforts to combat NO pollution.