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.

Earth-abundant, active and stable water splitting electrocatalysts operating in the same electrolyte at all pH values is important for many renewable energy conversion processes. We report here the first carbon nanomaterials-based metal-free water splitting electrocatalyst. The nitrogen, phosphorus and oxygen tri-doped porous graphite carbon@oxidized carbon cloth (ONPPGC/OCC) electrocatalyst can be prepared by a simple cost-effective method using aniline, phytic acid and OCC as precursors. Being a robust integrated three-dimensional porous bifunctional electrode, ONPPGC/OCC enables a high-performance basic water electrolyzer with 10 mA cm⁻² at a cell voltage of 1.66 V. Additionally, this electrode offers excellent catalytic performance and durability under both neutral and acidic conditions.