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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 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.

We report the observation of a magnetic-field-assisted transient superconducting state in the two-dimensional electron gas existing at the interface of LaAlO 3 /SrTiO 3 heterostructures. This metastable state depends critically on the density of charge carriers in the system. It appears concomitantly with a Lifshitz transition as a consequence of the interplay between ferromagnetism and superconductivity and the finite relaxation time of the in-plane magnetization. Our results clearly demonstrate the inherently metastable nature of the superconducting state competing with a magnetic order in these systems. The coexistence of superconductivity and ferromagnetism in the conducting electronic layer formed at the interface of insulating oxides has thrown up several intriguing and as yet unanswered questions. An open question in this field is the energetics of the interplay between these two competing orders and the present observation goes a long way in understanding the underlying mechanism.

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