Effect of some operational parameters on the hydrogen generation efficiency of Ni-ZnO/PANI composite under visible-light irradiation

Abstract Ni x Zn 1− x O/Polyaniline hybrid photocatalysts are synthesized and used for the experiments of hydrogen production from water-splitting under visible irradiation. XRD, UV–vis DRS and SEM are used to characterize the prepared materials. It is shown that the Ni 2+ amount doped into ZnO controls its morphology and enhances its photoactivity for H 2 generation. Polyaniline (PANI) is shown to sensitize ZnO and to extend its light absorption toward the visible region. The hybrid photocatalyst with 10 mol% Ni 2+ and 10 wt.% PANI shows the maximum photocatalytic H 2 production for one hour of visible irradiation: ∼558 μmol while only ∼178 μmol in the presence of pure ZnO. Additives like sacrificial electron donors and carbonate salts are found to play a key role in the improvement of H 2 evolution. Thus, the hydrogen photoproduction efficiency increases in the order: thiosulfate > sulfide > propanol and HCO 3 −  > CO 3 2− .