Oxygen defect-rich In-doped ZnO nanostructure for enhanced visible light photocatalytic activity

Abstract

Developing high-efficiency photocatalyst for the degradation of environmental pollutants under visible light is ideal. In this study, indium-doped zinc oxide with rich oxygen vacancy defects (In–OV–ZnO) was successfully fabricated by using a facile solution method followed by annealing process. The morphological, structural, and optical properties of the as-synthesized samples were studied. The X-ray diffraction measurements revealed the positions of the main peaks in the synthesized samples with In3+ ions and oxygen vacancies were slightly shifted. The analysis of SEM and TEM showed that the In–OV–ZnO samples were in the nanoscale regime (20-50 nm) with hexagonal crystalline morphology. The UV–vis DRS spectra showed that In–OV–ZnO samples had the band gap value of 3.14 eV. Based on photocurrent analysis and photoluminescence studies, the oxygen vacancy of In–OV–ZnO favored the electron–hole pairs’ separation. Photocatalytic studies revealed that the In–OV–ZnO samples display better photocatalytic activities of methylene blue (MB) and methyl orange (MO) under visible light irradiation, which exhibited maximum degradations of 96.84% and 90.05%, respectively. The enhanced photocatalytic performance can be ascribed to the synergistic effect of the oxygen vacancy defects and the In3+ ions favoring efficient electron–hole separation, which provided several active sites. This work develops a study to enable an efficient and cost-effective design of novel photocatalysts and offers insight into the influence of surface defects in enhancing photocatalytic activity.