Dual effect of the coordination field and sulphuric acid on the properties of a single-atom catalyst in the electrosynthesis of HO.

Electrocatalytic synthesis of hydrogen peroxide (HO) the two-electron oxygen reduction reaction (2e ORR) is the ideal solution for on-site HO production. Herein, we propose a new strategy for creating new 2e ORR catalysts by introducing electron-deficient B atoms and electron-rich N atoms to regulate the coordination field of metal ions on a graphene substrate. Through the first-principles density functional theory (DFT) calculations, NiNB-h was screened out as it had a low overpotential (0.12 V) for 2e ORR. The Bader charge analysis revealed that B atoms increased the charge density of Ni atoms, leading to moderate binding of O. Furthermore, the combination of molecular dynamic (AIMD) calculations and DFT calculations in an HSO environment revealed a new reaction mechanism of HO synthesis, involving proton-transfer between activated O and HSO. Moreover, the rate-determining step (0.63 eV) of HO desorption in the presence of HSO was different from that of OOH* protonation (0.45 eV) under the gas phase. This difference is attributed to the hydrogen-bond network in the acid solution.