Enhanced photo-catalytic efficiency through dual-functional ZIF based materials: Fabrication and application as a degradation of organic dyes

Abstract

Photocatalytic technology is considered the most promising green technology for the degradation and removal of organic pollutants. In this paper, an innovative multifunctional photocatalytic material has been successfully prepared. The zeolitic-imidazolate-framework-67 (ZIF-67) was first synthesized by an easy and green approach. Then, a polydopamine (PDA) mid-layer was incorporated on its surface via dopamine self-polymerization, which not only serves as a stable linking agent, but also increases the amount of visible light captured and reduces the recombination of photogenerated electron-hole pairs. After the hydrolysis and hydrothermal process of tetrabutyl orthotitanate, the TiO2 nanoparticles were uniformly grafted on the surface, and finally, the hollow ZIF-67@PDA@TiO2 was successfully obtained. The prepared H-ZIF-67@PDA@TiO2 photocatalyst was characterized by various techniques, and further used for the photo degradation of a variety of dyes in wastewater in the presence of visible light. A degradation rate of almost 100% was achieved for Acid Fuchsin and Congo Red within 40 min, followed by Erythrosine B and Rose Bengal with a 99% degradation rate within 150 min. Moreover, the ZIF-67-based photocatalyst exhibited high stability and recyclability and maintained an excellent photocatalytic performance during continued cycling. Furthermore, the superoxide radical (•O2−) and the hydroxyl radical (•OH) were the primary and secondary reactive species during photodegradation. Overall, the excellent performance of this simple photocatalyst was clearly demonstrated, and its numerous advantages, such as low energy consumption, low cost, non-toxicity, and environmental friendliness, showing promising potential for its practical implementation.