Fabrication of Zn-Ti layered double oxide nanosheets with ZnO/ZnTiO3 heterojunction for enhanced photocatalytic degradation of MO, RhB and MB

Abstract

Zn-Ti layered double oxide (LDO) nanosheets were synthesized by a simple co-precipitation-calcination process for the enhanced photocatalytic degradation of methyl orange (MO), rhodamine B (RhB) and methylene blue (MB). ZnTi-LDOs nanosheets present higher photocatalytic efficiency for MO, RhB and MB removal, which is 5.4, 4.4 and 6.7 times of that of Zn-Ti layered double hydroxide (LDH), respectively. The photocatalytic activity of synthesized ZnTi-LDOs is greatly affected by the mole ratio of Zn/Ti, calcination temperature and pH value. It is found that the formation of ZnO/ZnTiO3 heterojunction in ZnTi-LDOs could effectively accelerate the rapid separation of charge carriers, and thus enhance the photocatalytic activity via enlarging the photoresponse range. The possible charge transfer mechanism for photocatalytic degradation of organic dyes by ZnTi-LDOs was proposed based on the active species test and UV–Vis diffuse reflectance spectra. The results of active species trapping experiments showed that ‧OH, ‧O2−, h+, e− all had effect on the degradation of RhB, and ‧OH played a major role. This study provides a new insight for the photocatalytic degradation of organic pollutants from wastewater by ZnTi-LDOs.