Studies into the Yb-doping effects on photoelectrochemical properties of WO3 photocatalysts

Abstract

Yb-doped WO₃ photocatalysts were prepared by co-sputtering Yb and WO₃ on FTO glass and then sintering at elevated temperatures in air. At sintering temperatures between 450 and 550 °C, the photocurrent densities of Yb-doped WO₃ photocatalysts were higher and more stable than those of pristine WO₃ photocatalysts. The Yb-doping effects on the photoelectrochemical properties were investigated using Raman, transient absorption and electrochemical impedance spectroscopies. Compared to pristine WO₃ photocatalysts, Yb-doped photocatalysts sintered at up to 550 °C consist of sub-stoichiometric WO_3−x due to the substitution of W⁶⁺ cations with Yb³⁺ dopants, displaying shorter electron–hole recombination times and higher levels of donor densities.