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.