Siti Lailatul N. Zulmajdi¹, Nur Izzah I. Zamri¹, Abdul Hanif Mahadi², Mohd Yameany H. Rosli³, Fairuzeta Ja’afar¹, Hartini M. Yasin¹, Eny Kusrini⁴, Jonathan Hobley^{1, 5}, Anwar Usman^1,

This paper describes the photocatalytic degradation of methylene blue (MB) in aqueous solution in the presence of TiO₂ nanoparticles (NPs) in different compositions of anatase and rutile phases under UV light irradiation. The different compositions of crystalline phases of TiO₂ NPs were synthesized using sol-gel method at the same temperature for various calcination times. The TiO₂ NPs were subjected to crystal phase, vibrational, size, and morphological characterizations. The photocatalytic degradation of MB revealed that anatase TiO₂ NPs have a superior catalytic activity in the front of rutile phase. This finding further suggested that low charge resistance and low electron-hole recombination probability lead to the acceleration of the OH• formation on the surface of anatase TiO₂ NPs.