Mohamad Haqzim Ayob, Wai Loon Leaw, Desmilia Putri Ramadhani, Dewi Mariyam, Hadi Nur
Photocatalytic degradation offers a sustainable solution for removing harmful dyes from wastewater, but the development of efficient and reusable catalysts remains a challenge. Cobalt oxide supported on silica-coated magnetite was synthesized and its performance as a photocatalyst for methylene blue degradation without a sacrificial agent was investigated. Cobalt oxide (Co3O4/SiO2@Fe3O4) was produced by the calcination of cobalt complex/SiO2@Fe3O4 at the temperature of 550 °C. The cobalt-based photocatalysts were characterized by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL), diffuse reflectance ultraviolet-visible (DRUV-vis) spectroscopy, and Brunauer–Emmett–Teller (BET) surface area analysis. In this study, Co3O4/SiO2@Fe3O4 was synthesized and evaluated as a photocatalyst for the degradation of methylene blue (MB) under UV and visible light irradiation. The composite exhibited significant photocatalytic activity, achieving 92% dye degradation within 150 min under UV light without the use of sacrificial agents. As demonstrated by photoluminescence spectroscopy, a low electron-hole recombination rate, which is correlated with a high content of surface oxygen vacancies and defects, is the key feature for achieving high photocatalytic activity of the cobalt oxide-based photocatalyst. © 2025 Wiley-VCH GmbH.
Centre for Sustainable Nanomaterials, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, UTM Johor Bahru, Johor, 81310, Malaysia; Department of Chemistry, Faculty of Mathematics and Natural Science, State University of Malang, Jl. Semarang 5, Malang, 65145, Indonesia
