TiO$_2$ photocatalysts were synthesized by facile sol–gel process with compensation of cetyltrimethylammonium bromide (CTAB). We report the influence of CTAB addition on morphological, electronic properties, stoichiometric and photocatalytic activity of anatase-enriched CTAB–TiO$_2$. Here CTAB acts as a good surface modifier. Observed quenched photoluminescence (PL) intensity signifies high charge separation rate and reduced recombination probability of charge carriers. CTAB takes part in trapping electrons, which hinders the recombination of electron–hole pairs. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses show the formation of oxygen vacancies and Ti$^{3+}$-defect states. These defect states are also confirmed from PL analysis. X-ray diffraction pattern reveals the increase of crystallinity of the catalyst sample on increasing CTAB amount in the TiO$_2$ matrix. The estimated decreasing nature of particle size of the samples claimed that agglomeration of particles was destroyed with addition of CTAB and the surface area increases accordingly. The broadening of XRD patterns for higher CTAB-assisted samples was attributed to the formation of point defects. Here, results show that the bridging oxygen vacancies and other defect states played a crucial role by interacting with water molecules and dissociation of the Ti-O bonds to form titanium ions. Photocatalytic activity of methylene blue degradation in UV light by varying catalyst loading was investigated. Kinetic modelling of degradation has been established in this study. Photodegradation of dye increases at higher amounts of catalysts due to thepresence of more OH. radicals in the active sites.