Dirac Nodal Arc Semimetal PtSn₄ : An Ideal Platform for Understanding Surface Properties and Catalysis for Hydrogen...

Conductivity, carrier mobility, and a suitable Gibbs free energy are important criteria that determine the performance of catalysts for a hydrogen evolution reaction (HER). However, it is a challenge to combine these factors into a single compound. Herein, we discover a superior electrocatalyst for a HER in the recently identified Dirac nodal arc semimetal PtSn₄ . The determined turnover frequency (TOF) for each active site of PtSn₄ is 1.54 H₂  s^-1 at 100 mV. This sets a benchmark for HER catalysis on Pt-based noble metals and earth-abundant metal catalysts. We make use of the robust surface states of PtSn₄ as their electrons can be transferred to the adsorbed hydrogen atoms in the catalytic process more efficiently. In addition, PtSn₄ displays excellent chemical and electrochemical stabilities after long-term exposure in air and long-time HER stability tests.