Surface galvanic formation of Co-OH on Birnessite and its catalytic activity for the oxygen evolution reaction

Low-cost, high-efficient catalysts for water splitting can be potentially fulfilled by developing earth-abundant metal oxides. In this work, surface galvanic formation of Co-OH on K0.45MnO2 (KMO) was achieved via the redox reaction hydrated Co2+ with crystalline Mn4+. The synthesis method takes place at ambient temperature without using any surfactant agent or organic solvent, providing a clean, green route design highly efficient catalysts. resulted in ultrathin nanoflakes high electrochemical area. X-ray absorption spectroscopy (XAS) and photoelectron (XPS) analysis confirmed changes oxidation state bulk species supported KMO. effect anions, such as chloride, nitrate sulfate, preparation catalyst evaluated spectrochemical means. XPS Time flight secondary ion mass spectrometry (ToF-SIMS) demonstrated that layer CoOxHy deposited KMO its electronic structure strongly depend anion precursor used during catalyst. particular, it found Cl- favors Co-OH, changing rate-determining step reaction, which enhances catalytic activity towards OER, producing most active OER alkaline media.