Photocatalytic degradation of methyl orange on ZnO-TiO2/SO42- heterojunction composites

ZnO-TiO2/SO42- (ZTOS) heterojunction composites were prepared by an inorganic precipitation-peptization method. It is found that the molar ratios of Zn : Ti have obvious influence on the ultraviolet (UV) light ab-sorption and morphology of ZTOS. The results of photocatalytic characterizations indicate that the degradation rate of methyl orange on ZTOS (90.34%) is significantly higher than that of on the pure TiO2 (43.58%). In addition, the ZTOS can holds 97% photocatalytic activity after cyclic stability measurements. The remarkable improved performance obtained on ZTOS is attributed to the stronger UV light absorption, large specific surface area and effective charges separation caused by the heterojunction structure of ZnO-TiO2. Furthermore, the active species for the decomposition of methyl orange on ZTOS are proposed to be the photo-generated holes and radicals of .O-2(-), .OH and SO4-. formed during photo-induced reactions.

Automated summary

ZnO-TiO2/SO42- (ZTOS) heterojunction composites were prepared using an inorganic precipitation-peptization method, exhibiting enhanced photocatalytic activity and stability. The molar ratios of Zn : Ti were found to significantly influence the performance. The heterojunction structure of ZnO-TiO2 provided stronger light absorption and efficient charge separation.