Photocatalytic reduction of potassium chromate by Zn-doped TiO2/Ti film catalyst

Abstract: The aim of this work was to investigate the photocatalytic (PC) reduction of potassium chromate by Zn-doped TiO2/Ti film catalysts. The film catalyst was prepared by plasma electrolytic oxidation method in H2SO4 solution with different dosages of ZnSO4. The composition and structure of the film catalysts was studied by XRD, SEM and EPMA. The removal rate of potassium chromate was investigated under the conditions of the different dosages of ZnSO4 and the initial concentration of chromate potassium, and the reductive product during the PC reduction process was analyzed. The results showed that the film catalyst was composed of anatase TiO2 and rutile TiO2 with the porous structure. When the dosage of ZnSO4 was 0.2g/L, the film catalyst presented the highest catalytic activity, which related to the amount and the crystal grain size of anatase TiO2 in the film. The PC reduction of potassium chromate by the film catalyst obeyed the pseudo-first-order kinetic equation. The UV–vis spectrum and XPS analyses proved that chromate Cr(VI) was reduced to Cr(III), which existed in the form of insoluble Cr(OH)3. [Copyright &y& Elsevier]