Pt4+as an Active Site for Oxygen Evolution Reaction in La1- xSr xCo1- yPt yO3

This study presents an investigation on the role of Pt4+ in Pt-doped La1-xSrxCoO3 (LSPtCO) perovskite for oxygen evolution reaction (OER) activity. LSPtCO with Pt in the +4 oxidation state shows the highest activity for OER in comparison to undoped La1-xSrxCoO3 (LSCO) and Pt metal-supported LSCO (Pt is in the zero oxidation state). These results indicate that a high oxidation state of Pt is favorable for the OER activity. Pt4+ is also shown as the active center for the OER reaction as its reductive treatment decreases the OER activity significantly. Thus, the formation of high-valent Pt is a key factor in fabricating an active OER catalyst. While Pt metal may not be a good catalyst for OER, Pt4+ is significantly superior, especially in LSCO.