Mitrofanovite, Layered Platinum Telluride, for Active Hydrogen Evolution.

Two-dimensional (2D) layered catalysts have been considered as a class of ideal catalysts for hydrogen evolution reaction (HER) because of their abundant active sites with almost zero Gibbs energy change for hydrogen adsorption. Despite the promising performance, the design of stable and economic electrochemical catalyst based on 2D materials remains to be resolved for industrial-scale hydrogen production. Here, we report layered platinum tellurides, mitrofanovite PtTe, which serves as an efficient and stable catalyst for HER with an overpotential of 39.6 mV and a Tafel slope of 32.7 mV/dec together with a high current density exceeding 7000 mA/cm. PtTe was synthesized as nanocrystals on a metallic molybdenum ditelluride (MoTe) template by a rapid electrochemical method. X-ray diffraction and high-resolution transmission microscopy revealed that the PtTe nanocrystals have a unique layered structure with repeated monolayer units of PtTe and PtTe. Theoretical calculations exhibit that PtTe with numerous edges shows near-zero Gibbs free-energy change of hydrogen adsorption, which shows the excellent HER performance as well as the extremely large exchange current density for massive hydrogen production.