Carbothermal synthesis of titanium oxycarbide as electrocatalyst support with high oxygen evolution reaction activity

Carbothermal reduction of semiconducting TiO2into highly conductive titanium oxycarbide (TiOxCy) was investigated. The thermally produced uniform carbon layer on TiO2(Degussa P25) protects the TiO2nanoparticles from sintering and, at the same time, supplies the carbon source for doping TiO2with carbon. At low temperatures (e.g., 700 °C), carbon only substitutes part of the oxide and distorts the TiO2lattice to form TiO2−xCxwith only substitutional carbon. When the carbon-doped TiO2is annealed at a higher temperature (1100 °C), x-ray diffraction and x-ray photoelectron spectroscopy results showed that TiOxCy, a solid solution of TiO and TiC, was formed, which displays different diffraction peaks and binding energies. It was shown that TiOxCyhas much better oxygen revolution reaction activity than TiO2or TiO2−xCx. Further studies showed that the TiOxCyobtained can be used as a support for metal electrocatalyst, leading to a bifunctional catalyst effective for both oxygen reduction and evolution reactions.