Synthesis of Porous ZnO Photocatalyst Using Carbon Microsphere Template for Methylene Blue Degradation

Abstract

Porous zinc oxide photocatalysts were successfully synthesized using carbon microsphere templating method. This study investigated the effect of carbon microsphere templates on the physicochemical properties and photocatalytic performance of ZnO in methylene blue degradation. Carbon microspheres were prepared via hydrothermal method and subsequently used as templates to obtain porous ZnO through wet impregnation route. The carbon templates exhibited a uniform spherical morphology with an average diameter of less than 1 µm and an amorphous structure, while the resulting ZnO showed a highly porous structure with good crystallinity, surface area of 9 m² g⁻¹, total pore volume of 0.034 cm³ g⁻¹, pore size of 5.9 nm and a band gap of 3.17 eV. Photocatalytic tests revealed that ZnO degradation efficiency increased with UV irradiation time, reaching the highest value of 39.3 ± 0.2% at 150 min, and the reaction followed first-order kinetics with a rate constant of 0.0032 ± 0.0001 min⁻¹. These results explained that carbon template-assisted synthesis is a powerful, tunable approach for tailoring ZnO structure and provides a basis for developing a photocatalyst for environmental applications.