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

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 degrees 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 degrees C consist of sub-stoichiometric WO3-x due to the substitution of W6+ cations with Yb3+ dopants, displaying shorter electron-hole recombination times and higher levels of donor densities.