Tuning oxygen vacancies on LaFeO3 perovskite as efficient electrocatalysts for oxygen evolution reaction

The oxygen vacancies in lanthanum-iron oxide perovskite were produced by plasma. The vacancy concentration was facilely tuned by plasma forming-gas following the order of Ar > O2 > H2/Ar. The oxygen vacancies obviously promoted oxygen evolution reaction (OER) performance. O2-plasma produced a moderate concentration of oxygen vacancy in LaFeO3 which exhibited the highest OER activity. DFT calculations confirmed that the weak hydroxyl adsorption was improved by oxygen vacancy, but excessive oxygen vacancies reduced the OER activity with strong hydroxyl adsorption energy.