Quaternary\nMixed Oxides of Non-Noble Metals with Enhanced\nStability during the Oxygen Evolution Reaction

Robust electrocatalysts\nrequired to drive the oxygen evolution\nreaction (OER) during water electrolysis are still a missing component\ntoward the path for sustainable hydrogen production. Here a new family\nof OER active quaternary mixed-oxides based on X–Sn–Mo–Sb\n(X = Mn, Fe, Co, or Ni) is reported. These nonstoichiometric mixed\noxides form a rutile-type crystal structure with a random atomic motif\nand diverse oxidation states, leading to the formation of cation vacancies\nand local disorder. The successful incorporation of all cations into\na rutile structure was achieved using oxidizing agents that facilitates\nthe formation of Sb<sup>5+</sup> required to form the characteristic\noctahedral coordination in rutile. The mixed oxides exhibit enhanced\nstability in both acidic and alkaline environments under anodic potentials\nwith no changes in their crystal structure after extensive electrochemical\nstress. The improved stability of these mixed oxides highlights their\npotential application as scaffolds to host and stabilize OER active\nmetals.