The synergetic effect of grafted hetero bimetallic ions/sulfated-TiO2 on the conversion of greenhouse gases under UV–vis irradiation

Abstract

Grafted hetero bimetallic ions (Fe3+ and Zn2+ ions) / sulfated - TiO2 was synthesized by impregnation method. The effect of the cation loading, as well as the synergistic effects of the cation and anion loading on TiO2 were investigated on the photocatalytic reduction of greenhouse gases (CO2 and CH4) under UV–vis irradiation. XRD, BET, nitrogen adsorption–desorption isotherms, SEM, EDX, elemental mapping, FT-IR, UV–vis DRS analyses were applied to characterize the prepared catalysts. The results represented the excellent dispersion and successful incorporation of the elements on the catalyst surface. The XRD results confirmed that the ions have not entered the crystalline lattice of TiO2, and have remained only on the surface of the crystal. As depicted by UV–vis analysis, the band gap of catalysts decreased after the ions loading, and SO42−/Fe3+-Zn2+/ TiO2, by a band gap of about 2.1 eV, represented the most visible light photocatalytic activity among the others. The photo-activity tests revealed that the addition of SO42- to Fe3+-Zn2+/TiO2 increased the photocatalytic conversion of CO2 and CH4 from 7 % to 12 % and 10 %–15 %, respectively. Finally, the growth mechanism for the formation of the ions grafted TiO2 was clarified in detail on the chemistry concept. In addition, the possible mechanism of the catalyst performance, as well as the reaction pathways were investigated in order to better understand the removal process.