Oxygen vacancies induced by charge compensation tailoring Ni-doped Co3O4 nanoflakes for efficient hydrogen evolution

The electronic structure modulation of the catalysts shows great significance towards hydrogen evolution reaction (HER). A charge compensation was realized by doping octahedral Ni2+ ions into the Co3O4 lattice, where the oxygen vacancies generate to maintain the electric neutrality. The oxygen vacancies lead to the local lattice distortion of Co3O4, trigger the concomitant electron redistribution, as well as optimize the d-band center of Ni-Co3O4. Then, the accelerated charge transfer and matter conversion boost the HER kinetics of Ni-Co3O4. As expected, the obtained Ni-Co3O4 catalyst exhibits the brilliant HER catalytic performance with a low overpotential of only 47 mV at 10 mA cm−2, and a Tafel slope of 46 mV dec−1. The density function theory calculations verify that this charge compensation strategy could efficiently promote the water dissociation and hydrogen transformation kinetics. Our work paves an effective avenue for rationally contriving high-efficiency catalysts towards HER.