ABSTRACT Graphene‐supported titania (TiO 2 ) nanopowder is widely studied for photocatalytic contaminant degradation; however, the effect of graphene on tuning the internal mesoporous network of TiO 2 remains underexplored. This study provides a deeper understanding of the enhanced photocatalytic performance of graphene‐supported titania by uncovering the architectural modifications in the mesoporous structure of the original nanopowder. Specifically, exfoliated–reduced graphene oxide (Ex‐rGO) was synthesized using a physicochemical method. The Ex‐rGO nanosheets, in varying concentrations (0.1%, 0.2%, and 0.4%), were added to the titania precursor as hard templates for the growth of TiO 2 nanoparticles. The resulting graphene‐supported titania nanocomposites, TiO 2 /Ex‐rGO (0.1%–0.4%), were characterized to evaluate their physical, chemical, crystallographic, and optical properties. The photocatalytic performance of the reference TiO 2 , TiO 2 /Ex‐rGO (0.1%), TiO 2 /Ex‐rGO (0.2%), and TiO 2 /Ex‐rGO (0.4%), measured by determining degradation of methylene blue (MB) dye, was found to be 72.62%, 79.58%, 94.63%, and 82%, respectively, in 2 h of UV exposure. Although TiO 2 /Ex‐rGO (0.4%) exhibited the lowest electron–hole recombination among all synthesized titania nanopowders, the highest photocatalytic degradation rate was achieved with an optimal Ex‐rGO concentration of 0.2% in the TiO 2 nanoparticles. This unexpected response was attributed to the rapid diffusion of dye molecules into the internal porous networks, facilitated by the relatively large average pore diameter of 13.78 nm and the widely open porous structure observed in TiO 2 /Ex‐rGO (0.2%). This study, for the first time, revealed that incorporating graphene nanosheets within the titania matrix can favorably tailor the mesoporous architecture of the parent nanopowder, enhancing pore accessibility and thereby boosting photocatalytic performance.
Singh et al. (Fri,) studied this question.