Dirac Nodal Arc Semimetal PtSn(4): An Ideal Platform for Understanding Surface Properties and Catalysis for Hydrogen Evolution

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 PtSn(4). The determined turnover frequency (TOF) for each active site of PtSn(4) is 1.54 H(2) 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 PtSn(4) as their electrons can be transferred to the adsorbed hydrogen atoms in the catalytic process more efficiently. In addition, PtSn(4) displays excellent chemical and electrochemical stabilities after long‐term exposure in air and long‐time HER stability tests.