Activating HfX2 (X = S, Se and Te) for the hydrogen evolution reaction by introducing defects: a first-principles study

An ideal catalyst should have a relative hydrogen adsorption Gibbs free energy (DGH) close to zero [J. K. Norskov, et al., J. Electrochem. Soc., 2005, 152, J23]. However, most of the known catalysts cannot reach this standard. Based on first-principles calculations, we studied the hydrogen evolution reaction (HER) catalytic performance of pristine and defect (including vacancy and heteroatom doping) structures in terms of its DGH. We found that the DGH values of Co-doped HfS2 and P-doped HfSe2 are extremely close to zero, even closer than that of Pt (111), indicating that they are excellent catalysts. Moreover, we found that the source of the HER catalytic performance of Co-doped HfS2 is the reduction of electron accumulation of the active site S atom. Our work provides two potential ideal catalysts and provides guidance for the experimental group to search for suitable catalysts.

Automated summary

In this study, we investigated the catalytic performance of defect structures in the hydrogen evolution reaction (HER) using first-principles calculations. We found that Co-doped HfS2 and P-doped HfSe2 have DGH values extremely close to zero, indicating their excellent catalytic activity. The reduction of electron accumulation at the active site S atom was identified as the source of the HER catalytic performance of Co-doped HfS2.