Investigation of Strain and Transition-Metal Doping Effect on Hydrogen Evolution Reaction Catalysts of Mo<sub>2</sub>C, MoP, and Ni<sub>2</sub>P
Feng Zhang, Lei He, Sen Lian, Mingyue Wang, Xue Chen, Jikang Yin, Huaqing Pan, Junfeng Ren, Meina Chen
Abstract
For hydrogen evolution reaction (HER) catalysts, compared with experimental research, theoretical research, especially that based on strain, is scarce, and even some of the results are contradictory. In this paper, strain and transition-metal doping effects on high-performance HER catalysts Mo2C, MoP, and Ni2P were calculated. We found that applying a certain amount of strain (1 and 3% tensile strain for Mo2C, 3% compressive and 1 and 3% tensile strain for MoP, and 1% compressive and 1% tensile strain for Ni2P) can enhance the HER catalytic performance. H coverage can affect the HER catalytic performance, especially that of the P-terminated surface of MoP, the ΔG of which is very close to 0 with 7/9 H coverage. Compared with the experimental data, we inferred that the actual catalytic sites in the experiment may not be the sites where the Gibbs free energy is closest to 0. This may be attributed to the weak adsorption ability of the latter. We have also found that for Mo2C and MoP certain doping (Fe > Mn > Co > Ni for Mo2C, Fe > Mn for MoP) can enhance the HER catalytic performance; however, for Ni2P, these improvements are not obvious. Our article reveals the performance changes of HER catalysts from the perspective of strain and doping and would be helpful for the further development of HER catalysts.