Unveiling the Mechanisms Ruling the Efficient Hydrogen Evolution Reaction with Mitrofanovite Pt(3)Te(4)

[Image: see text] By means of electrocatalytic tests, surface-science techniques and density functional theory, we unveil the physicochemical mechanisms ruling the electrocatalytic activity of recently discovered mitrofanovite (Pt(3)Te(4)) mineral. Mitrofanovite represents a very promising electrocatalyst candidate for energy-related applications, with a reduction of costs by 47% compared to pure Pt and superior robustness to CO poisoning. We show that Pt(3)Te(4) is a weak topological metal with the [Image: see text] invariant, exhibiting electrical conductivity (∼4 × 10(6) S/m) comparable with pure Pt. In hydrogen evolution reaction (HER), the electrode based on bulk Pt(3)Te(4) shows a very small overpotential of 46 mV at 10 mA cm(–2) and a Tafel slope of 36–49 mV dec(–1) associated with the Volmer–Heyrovsky mechanism. The outstanding ambient stability of Pt(3)Te(4) also provides durability of the electrode and long-term stability of its efficient catalytic performances.