PtSe2/Pt heterointerface with reduced coordination for boosted hydrogen evolution reaction.

PtSe 2 is a typical noble metal dichalcogenide (NMD) that holds promising possibility for next-generation electronics and photonics. However, when applied in hydrogen evolution reaction (HER), it exhibits sluggish kinetics due to the insufficient capability of absorbing active species. Here, we construct PtSe 2 /Pt heterointerface to boost the reaction dynamics of PtSe 2 , enabled by an in-situ electrochemical method. It is found that Se vacancies are induced around the heterointerface, reducing the coordination environment. Correspondingly, the exposed Pt atoms at the very vicinity of Se vacancies are activated, with enhanced overlap with H 1s orbital. The adsorption of H • intermediate is thus strengthened, achieving near thermoneutral free energy change. Consequently, the as-prepared PtSe 2 /Pt exhibits extraordinary HER activity even superior to Pt/C, with an overpotential of 42 mV at 10 mA/cm 2 and a Tafel slope of 53 mV/dec. This work raises attention on NMDs toward HER and provides insights for the rational construction of novel heterointerfaces.