Isostructural Oxides Sr3Ti2−xMxO7−δ (M = Mn, Fe, Co; x = 0, 1) as Electrocatalysts for Water Splitting

The correlation of the electrocatalytic activity with electrical conductivity, oxygen-vacancies, and electronegativity have been studied in a series isostructural oxides, having so-called Ruddlesden-Popper structure. structures these materials comprise transition metals that are octahedrally coordinated to form network bilayer stacks. These catalytically active for both half-reactions water-splitting, namely oxygen-evolution reaction (OER) hydrogen-evolution (HER). They show systematic increase progression from Sr3Ti2O7 Sr3TiMnO7, Sr3TiFeO7−δ, Sr3TiCoO7−δ. kinetic studies using Tafel method indicate same trend across series, where best catalyst also has fastest kinetics HER OER. In addition, is observed concentration as well conductivity wide range temperatures, 25 °C–800 °C. material shows activity, i.e., Sr3TiCoO7−δ, highest greatest oxygen vacancies series. correlations this work trends performance may be related electronegativity, electron occupancy eg orbitals, which can affect strength sigma interactions between intermediates.