Tuning Ni dopant concentration to enable co-deposited superhydrophilic self-standing Mo2C electrode for high-efficient hydrogen evolution reaction

Abstract

Ni doping is an effective way to change the electronic structure of molybdenum carbide (Mo2C) to promote the hydrogen evolution reaction (HER) performance. However, the relationship between the Ni dopant concentration and HER activity remains to be explored. Herein, we prepare self-sanding Mo2C electrodes with different Ni concentrations, and employ density functional theory (DFT) calculations along with electrochemical tests to investigate the effect of the Ni dopant concentration on HER activity. The Mo and C come from the co-deposition of MoO42- and CO32- on a Ni substrate that supplies Ni dopant. The concentration of Ni dopant can be tuned by adjusting the temperature. The HER performance of the Mo2C electrodes with various Ni dopant concentrations is in line with DFT calculations that the optimized Ni-Mo2C-0.67 electrode has a lowest ΔGH* value of − 0.13 eV. Altogether, this work sheds light on controllably designing Ni-doped Mo2C electrodes for splitting water.