CuOx-TiO2 junction: what is the active component for photocatalytic H2 production?

CuOx based junctions e.g. CuOx-TiO2 have been demonstrated to be very effective in photocatalytic H2 production, but the active component at the junction is less understood. We herein report that an as-prepared CuOx-TiO2 photocatalyst undergoes an in situ restructuring process during photocatalytic H2 production under solar light irradiation to form the active Cu2O-TiO2 interfacial structure on the surface. These results unambiguously demonstrate that Cu2O is the active copper species in CuOx-TiO2 photocatalysts.