Synthesis, characterization and optimization of photocatalytic activity of TiO2/ZrO2 nanocomposite heterostructures

•TiO2/ZrO2 nanocomposite was synthesized via hybrid sol–gel method.•Photocatalytic efficiency was found to be higher than Degussa P25.•The optimum loading amount of ZrO2 on TiO2 was found to be 6.0molar%.•The synthesized nanocomposite showed enhanced stability. Titanium dioxide/zirconium dioxide nanocomposites were synthesized using a simple and modified sol–gel method. The synthesized particles were characterized through SEM, TEM, XRD, and DTA/TGA. SEM analysis shows micrographs with irregular and sharp edged particles. TEM analysis shows spherical particles of average diameter 10.5nm. Tetragonal structure of TiO2/ZrO2 nanocomposite particles with stabilized anatase phase was confirmed by XRD studies. The average crystallite size was calculated from XRD, using Scherrer's formula. Band gap was calculated from the DRS spectra using Kubelka-Munk function and Photoluminescence (PL) was done to study the recombination rate of charge carriers. Results showed a considerable increase in band gap on ZrO2 addition and subsequent decrease in recombination rate. Impedance study showed a significant decrease in dielectric characteristics on ZrO2 addition. Photocatalytic activity of the synthesized catalysts was studied by degradation of an azo-dye, Ponceau BS, using ultra-violet source of light. Optimum activity was observed on 6.0% ZrO2 loading.