Titanium Dioxide/N-Doped Graphene Composites as Non-Noble Bifunctional Oxygen Electrocatalysts.

Bifunctional oxygen electrocatalysts are essential in the development of low-temperature unitized regenerative fuel cells (URFCs), as a promising alternative for storing energy via hydrogen. TiO 2 , as a semiconductor material, is commonly not established as an active electrocatalyst for oxygen reduction and oxygen evolution due to its poor electrical conductivity and low reactivity. Here, we demonstrated that composites composed of TiO 2 and N-doped graphene can be active in oxygen reduction and evolution reactions in an alkaline environment. Combination factors such anatase/rutile interaction, N-doping graphene, and the presence of Ti 3+ /Ti-N species raise the active sites and improve the electrochemical activity. Our results may afford an opportunity to develop a non-noble and promising electrocatalyst in energy storage technology.