Influence of tunable pore size on photocatalytic and photoelectrochemical performances of hierarchical porous TiO2/C nanocomposites synthesized via dual-Templating

TiO 2 /C nanocomposites with hierarchical porous framework were synthesized by the dual-templation method with ice and silica as the hard template. Silica of different dimensions was used as the knob to modify the TiO 2 /C pore structure and to control anatase-rutile transformation. The prepared TiO 2 /C nanocomposites with pores at three different scales with micro-, meso - and macro-pores not only prohibited aggregation of nanoparticles but also shortened the transportation distance of charge carriers. TiO 2 /C fabricated with 22   nm colloid silica as the template showed superior photocatalytic performances of 4.0 and 10.7 times of the commercial benchmark P25 under UV and visible light irradiation, respectively. The TiO 2 /C composites also showed excellent photoelectrochemical (PEC) performances with the photocurrent density of 6.3   mA/cm 2 that is 11.2 times of the control sample. The results demonstrated that the silica dimension serves a significant role for optimization of the TiO 2 /C microstructure including particle size, phase composition, surface area and thus improvement in photoelectrochemical and photocatalytic properties.