Improved photoelectrochemical performance of Ti-doped alpha-Fe2O3 thin films by surface modification with fluoride.

CoF(3) aqueous solution was used to modify the surface of Ti-doped iron oxide thin film photoanodes to negatively shift the flat-band potential and allow photogenerated electrons to directly reduce water to hydrogen without an external bias; the zero bias performance was further improved by the use of glucose (a biomass analog) to bypass the relatively slow oxygen evolution reaction to provide a source of electrons to rapidly consume photogenerated holes.