Synergistic dual doping of B and Ni: unraveling electronic modulation in Co3O4 for high-selectivity ammonia synthesis with enhanced yield via electrocatalysis

Electrocatalytic nitrate reduction reaction (NO 3 RR) represents a promising approach for regulating the global nitrogen cycle and serves as a crucial complementary method for ammonia synthesis. However, NO 3 RR is a complex reduction process involving the transfer of eight electrons and nine protons. Therefore, it is difficult for catalysts with a single catalytic site to maintain an advantage throughout the NO 3 RR process. Consequently, the fabrication of catalysts with synergistic effects to achieve both high efficiency and selectivity remains a formidable challenge. Herein, a simple precipitation-calcination process was employed to successfully introduce boron (B) and nickel (Ni) elements into Co 3 O 4 (B/Ni-Co 3 O 4 ) simultaneously. Impressively, the as-prepared B/Ni-Co 3 O 4 catalyst exhibited a remarkable NH 3 yield of 17.2 mg·h −1 ·mg cat −1 and a high FE of 97.2 % at −0.5 V relative to the reversible hydrogen electrode (RHE). Density functional theory (DFT) computations uncovered a cooperative effect between B and Ni dopants, specifically: B doping exhibited appreciable efficacy in NO 3 – adsorption, and the Ni dopant showed notable activity in promoting the conversion of NO 2 − . Further DFT calculations identified the *NO → *NOH step as rate-determining and revealed that B-Ni co-doping diminishes its thermodynamic energy barrier. Concurrently, experimental measurements showed that such co-doping lowers the onset potential to −0.06 V vs. RHE. This dual doping strategy significantly accelerates the electroreduction of NO 3 − to NH 3 .