Boosting the Hydrogen Evolution Reaction Performance of P-Doped PtTe Nanocages via Spontaneous Defects Formation.

PtTe , a member of the noble metal dichalcogenides (NMDs), has aroused great interest in exploring its behavior in the hydrogen evolution reaction (HER) due to the unique type-II topological semimetallic nature. In this work, a simple template-free hydrothermal method to obtain the phosphorus-doped (P-doped) PtTe nanocages with abundant amorphous and crystalline interface (A/C-P-PtTe ) is developed. Revealed by density functional theory calculations, the atomic Te vacancies can spontaneously form on the basal planes of PtTe by the P doping, which results in the unsaturated Pt atoms exposed as the active sites in the amorphous layer for HER. Owing to the defective structure, the A/C-P-PtTe catalysts have the fast Tafel step determined kinetics in HER, which contributes to an ultralow overpotential (η = 28 mV at 10 mA cm ) and a small Tafel slope of 37 mV dec . More importantly, benefiting from the inner stable crystalline P-PtTe nanosheets, limited decay of the performance is observed after chronopotentiometry test. This work reveals the important role of the inherent relationship between structure and activity in PtTe for HER, which may bring another enlightenment for the design of efficient catalysts based on NMDs in the near future.