Designing electrocatalysts with high-performance for both reduction and oxidation reactions faces severe challenges. Here, the uniform and ultrasmall (~3.4 nm) high-entropy alloys (HEAs) Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇ nanoparticles are synthesized by a simple low-temperature oil phase strategy at atmospheric pressure. The Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇/C catalyst exhibits excellent electrocatalytic performance for hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR). The catalyst shows ultrasmall overpotential of 11 mV at the current density of 10 mA cm⁻², excellent activity (10.96 A mg⁻¹_Pt at −0.07 V vs. reversible hydrogen electrode) and stability in the alkaline medium. Furthermore, it is also the efficient catalyst (15.04 A mg⁻¹_Pt) ever reported for MOR in alkaline solution. Periodic DFT calculations confirm the multi-active sites for both HER and MOR on the HEA surface as the key factor for both proton and intermediate transformation. Meanwhile, the construction of HEA surfaces supplies the fast site-to-site electron transfer for both reduction and oxidation processes.

Exploring a simple, fast, solvent-free synthetic method for large-scale preparation of cheap, highly active electrocatalysts for industrial hydrogen evolution reaction is one of the most promising work today. In this work, a simple, fast and solvent-free microwave pyrolysis method is used to synthesize ultra-small (3.5 nm) Ru-Mo₂C@CNT catalyst with heterogeneous structure and strong metal-support interaction in one step. The Ru-Mo₂C@CNT catalyst only exhibits an overpotential of 15 mV at a current density of 10 mA cm⁻², and exhibits a large turnover frequency value up to 21.9 s⁻¹ under an overpotential of 100 mV in 1.0 M KOH. In addition, this catalyst can reach high current densities of 500 mA cm⁻² and 1000 mA cm⁻² at low overpotentials of 56 mV and 78 mV respectively, and it displays high stability of 1000 h. This work provides a feasible way for the reasonable design of other large-scale production catalysts.