Fabrication of Bi3+-doped ZnO with enhanced photocatalytic performance

ZnO and Bi3+-doped ZnO photocatalysts with different molar ratio of Bi/Zn were prepared by a parallel flaw precipitation method. The photocatalysts prepared were characterized by BET surface area, X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopic techniques (XPS), UV/Vis diffuse reflectance spectroscopy (DRS) and surface photovoltage spectroscopy (SPS), respectively. The results show that doping Bi into ZnO increases the BET surface area. The XRD spectra of the Bi3+-doped ZnO photocatalysts calcined at 573 K show only the characteristic peaks of wurtzite-type. Doping Bi3+ into ZnO influences the response to the light and the photoinduced charge separation rate, changes the morphology of ZnO and induces binding energy value of Zn2p3/2 shift. The photocatalytic activity of Bi3+-doped ZnO photocatalysts for decolorization of methyl orange (MO) solution was evaluated, of all the photocatalysts prepared, the Bi3+-doped ZnO with 5%Bi possesses the best photocatalytic activity among the experimented compositions and the possible reason was discussed.

In general, the strong SPS response corresponds to the high separation rate of photoinduced charge carriers on the basis of the SPS principle. The photovoltage of Bi3+-doped ZnO is higher than that of ZnO, thus, it can be confirmed that the Bi3+-doped ZnO has a higher charge separation rate than the ZnO sample. Among these samples, 5%Bi has the highest charge separation rate.Highlights► Bi3+ increases the BET surface area and changes the morphology of ZnO. ► Bi3+ induces binding energy value of Zn 2p3/2 shift. ► The photoinduced charge separation rate has been changed. ► The photocatalytic activity has been greatly influenced.