Photoelectrochemical application of mesoporous TiO2/WO3 nanohoneycomb prepared by sol–gel method

• Mesoporous TiO2/WO3 nanohoneycomb was prepared by sol–gel method.
• Optical absorption of TiO2/WO3 revealed a red shift and smaller band gap energy.
• It showed a better photoelectrochemical efficiency of water splitting.
• TiO2/WO3 has higher reactive surface area and better separation efficiency.

A mesoporous TiO2/WO3 nanohoneycomb at a molar ratio of 3:1 was prepared by sol–gel method for photoelectrochemical splitting of water. In order to create a highly porous structure, the composite TiO2/WO3 with a block copolymer internal template was deposited on the substrate covered with polystyrene (PS) nanospheres. A mesoporous TiO2/WO3 composite nanohoneycomb was obtained after removing the PS spheres and copolymer by thermal treatment. It exhibited a lower band gap energy than TiO2 so that the optical absorption edge was shifted toward the visible light region. It also showed a better photoelectrochemical efficiency of water splitting and higher production of hydrogen due to lower energy gap, higher reactive surface area, and better charge separation efficiency.