Display omitted •Microwave-assisted hydrothermal method is used to prepare phase pure anatase TiO2.•TiO2 particles are nanosized and mesoporous in nature.•TiO2 particles exhibited very high N2 adsorption capacity.•Photodegradation efficiency of 98% was achieved in degrading methylene blue dye using TiO2 particles. Among the different polymorphs of TiO2, the anatase form has the highest photocatalytic activity. However, preparing anatase TiO2 typically requires long reaction times, high pressures, or both. Therefore, it is important to develop easy and quick methods to prepare anatase TiO2. In these lines, an easy microwave-assisted hydrothermal method is used in this work to prepare mesoporous and phase pure anatase TiO2 nanospheres (ATNS) with an average crystallite size of ∼ 10 nm. Titanium butoxide and methanol are used as the precursor and solvent, respectively, to prepare ATNS. Due to its moderate loss tangent value of ∼ 0.659, methanol aids in the efficient absorption of microwaves and rapid local heating for the reaction to complete quickly, leading to the formation of TiO2 nanospheres with mesoporosity, a high specific surface area of 60.46 m2/g, and a high N2 adsorption capacity. ANTS photodegrade methylene blue dye with an efficiency as high as 98 %. The enhanced intrinsic photocatalytic activity of ATNS is attributed to the combined effect of mesoporosity, high specific surface area, and high N2 adsorption capacity.