Photoactivity Enhancement of TiO2 Nanoparticle-decorated ZnO as a Photocatalyst in Methylene Blue Degradation

Abstract

Zinc Oxide (ZnO) and Titanium Dioxide (TiO2) are metal oxides that are commonly used as photocatalysts material due to photoactivity characteristics. ZnO has a better reduction potential, and high electron mobility, but has a lower contact surface area than TiO2. On the other side, TiO2 has a better photoactivity to degrade pollutants referring to high surface area but has lower electron mobility compared to that ZnO. The combination of these two metal oxides is estimated can produce a better photocatalytic activity due to the advantages of each characteristic. Therefore, in this research, the ZnO-TiO2 (1:1) was prepared and investigated. ZnO nanoparticle was synthesized by the sol-gel method using zinc acetate dihydrate as a precursor, before calcining process, anatase TiO2 powder was added to form the composite. Structural, morphological, and optical characteristics of composite powders were analyzed by using XRD, TEM, UV-Vis Spectroscopy, and PL Spectroscopy. The concentration degradation of methylene blue in a solution containing composite material was observed to determine the photocatalytic activity under UV light irradiation for 30 minutes. The XRD spectrum shows the anatase phase of TiO2 and hexagonal wurtzite of ZnO crystal structure. Based on TEM imaging ZnO nanoparticles were attaching to TiO2 surfaces estimated due to van der walls bond. The ZnO/TiO2 shows a better photoactivity up to 20 minutes reaction with a higher degradation constant rate that indicates faster methylene blue degradation.