Surface interaction of Ni based electrocatalyst with hydrogen peroxide

Abstract In this study, non-stoichiometric Ni–O thin films were synthesized by magnetron sputtering, enabling precise control over their morphology independently of the chemical composition. X-ray diffraction indicated the presence of crystalline Ni(111) planes, while Raman confirmed amorphous nickel oxide. Samples with the various amount of crystalline Ni were grown. X-ray photoelectron spectroscopy further revealed a mixture of metallic Ni and partially oxidized Ni–O species. Electrochemical analysis demonstrated that the thin films characterized by highly abundant Ni(111) planes exhibit catalytic activity for H 2 O 2 detection, with the current density of − 1.64 × 10 − 4 A/cm 2 . To gain deeper insight into the underlying mechanisms, density functional theory calculations were performed, showing that metallic sites on Ni(111) offer stronger interaction for OH groups than amorphous NiO, with average adsorption energies of − 3.76 and − 1.86 eV, respectively. The simulations also indicated that OH groups from H 2 O 2 preferentially dock onto bridge sites of Ni(111). These findings highlight the significant potential of non-stoichiometric Ni–O systems for electrochemical sensing applications and provide valuable understanding of H 2 O 2 interactions with oxides.