Realizing the Excellent HER Performance of Pt3Pb2S2 by d-Orbital Electronic Modulation.

Exploring new excellent electrocatalysts for the hydrogen evolution reaction (HER) is of significance for the development of hydrogen energy. Herein, a ternary chalcogenide (Pt3Pb2S2) is successfully designed and synthesized using layered PtS2 as a matrix. The energy level of the Pt 5d orbital is upshifted to the Fermi surface after replacing S atoms by Pb atoms, which results in the high conductivity of Pt3Pb2S2. In addition, the low-coordinated Pt atoms inserted in the voids of [Pt2Pb2S2] layers have a lower free energy of H* adsorption than do metallic Pt atoms, which endows Pt3Pb2S2 with excellent HER performance. The overpotential and Tafel slope of Pt3Pb2S2 toward HER activity are measured to be 43 mV at 10 mA cm-2 and 43 mV dec-1, respectively. More importantly, Pt3Pb2S2 shows high intrinsic HER catalytic activity and long-term stability. This work provides a promising strategy for designing novel excellent transition-metal chalcogenide electrocatalysts.