Carbothermal Shock Synthesis of High Entropy Oxide Catalysts: Dynamic Structural and Chemical Reconstruction Boosting the Catalytic Activity and Stability toward Oxygen Evolution Reaction

Mixed transition-metals (TM) based catalysts have shown huge promise for water splitting. Conventional synthesis of nanomaterials is strongly constrained by room-temperature equilibria and Ostwald ripening. Ultra-fast temperature cycling enables the metastable metallic phases high entropy alloy nanoparticles, which later transform to oxide/hydroxide nanoparticles upon use in aqueous electrolytes. Herein, an situ non-noble metal oxide (HEO) on carbon fibers rapid Joule heating quenching reported. Different compositions ternary senary (FeNiCoCrMnV) HEO show higher activity towards catalyzing oxygen evolution reaction (OER) compared a noble IrO2 catalyst. The synthesized also two orders magnitude stability than IrO2, due stronger carbide-mediated intimacy with substrate, activated through OER process. Alloying elements Cr, Mn V affect promoting different oxidation states catalytically active TM (Fe, Ni Co). Dissolution less stable (Mn, Cr) leads enhancements activity. Dynamic structural chemical perturbations activate under conditions, leading enlargement ECSA forming mixed single atom ultra-fine oxyhydroxide HEOs.