Electronic Structure Engineering of Pt Species over Pt/WO 3 toward Highly Efficient Electrocatalytic Hydrogen Evolution.

Pt-based supported materials, a widely used electrocatalyst for hydrogen evolution reaction (HER), often experience unavoidable electron loss, resulting in a mismatching of electronic structure and HER behavior. Here, a Pt/WO 3 catalyst consisting of Pt species strongly coupled with defective WO 3 polycrystalline nanorods is rationally designed. The electronic structure engineering of Pt sites on WO 3 can be systematically regulated, and so that the optimal electron-rich Pt sites on Pt/WO 3 -600 present an excellent HER activity with only 8 mV overpotential at 10 mA cm -2 . Particularly, the mass activity reaches 7015 mA mg -1 at the overpotential of 50 mV, up to 26-fold higher than that of the commercial Pt/C. The combination of experimental and theoretical results demonstrates that the O vacancies of WO 3 effectively mitigate the tendency of electron transfer from Pt sites to WO 3 , so that the d-band center could reach an appropriate level relative to Fermi level, endowing it with a suitable Δ G H ∗ $\Delta {G_{{{\rm{H}}^ * }}}$ . This work identifies the influence of the electronic structure on catalytic activity.