In summary, we have demonstrated a facile hydrothermal synthesis of mesoporous anatase TiO2, and Ag–TiO2 by the impregnation method using water-dispersible Ag obtained from green carambola extract at room temperature. BETsurface area, pore volume and pore size of TiO2 decreased with Ag doping. The HR-TEM of the TiO2samples show dspacing of 0.35 nm corresponding to the (101) lattice planes of
anatase TiO2planes, while in Ag–TiO2samples, the d-spacing of 0.23 nm corresponding to (111) plane of Ag confirmed the presence of Ag nanoparticles. The initial higher efficiency of photocatalytic degradation of MB in the presence of Ag–TiO2 was due to electron trapping of Ag to enhance electron–hole separation, followed by decrease of its efficiency after a certain period of time caused due to lower surface area and pore size compared to pure anatase TiO2. Therefore, dual properties i.e., electron trapping efficiency of Ag in Ag–TiO2 , and higher surface area and pore size of undoped anatase TiO2 played a significant role to increase the efficiency for MB degradation.