Co-catalysis: Role of Organic Cations in Oxygen Evolution Reaction on Oxide Electrodes

Co-catalysis is promising approach towards enhancing activity of heterogeneous and homogeneous electrocatalysts. We report such synergic catalysis involving organic xanthylium-based catalyst, Xan2+, and oxides formed on the electrode surface. The oxygen evolution reaction (OER) was observed on working electrodes such as gold, platinum, glassy carbon, and boron-doped diamond, while some electrodes (titanium and fluorine-doped tinoxide) exhibited no OER activity. Based on experimental data supported by previously reported calculations, we propose a mechanism in which oxidized Xan2+ activates electrode surfacetowards the rate-determining O-O bond formation. In light of our findings, efficient OER electrocatalysis can be achieved using materials that strongly bind oxygen species and electron-deficient organic cations. This work has implications for energy storage systems that utilize OER.