Beneficial effect of Nb doping on the photoelectrochemical properties of TiO2 and TiO2-polyheptazine hybrids

Nb-doped TiO2 in pure anatase form prepared by spray drying exhibits enhanced photoelectrochemical performance both in its bare form (under UV irradiation) and when used as an electron collector in TiO2-polyheptazine hybrid photoanodes for water photooxidation under visible (λ>420 nm) light. The optimum Nb-doping concentration was 0.1 at%, and the enhancement of photocurrents was found to be chiefly due to enhanced mobility of electrons in Nb-doped TiO2. Accordingly, the beneficial effect of Nb doping on photocurrent generation in hybrid photoanodes was pronounced particularly at longer irradiation wavelengths and lower bias potentials.