Ordered mesoporous WO3 thin films electrodeposited with surfactant for photocatalytic and electrochromic electrode.

초록

Tungsten oxide (WO3) is an indirect bandgap semiconductor with interesting photoconductive behavior that has potential applications as a low cost material for solar energy devices.[1,2] Because of its distinct photochromic response and intercalation properties (H+,Li+,Na+, and K+),[3] it has also found use in electrochromic devices and chemical sensors. For the hydrogen cations, the electrochromic process of tungsten oxide has been explained on the basis of the double intercalation of a proton and an electron to form a colored tungsten bronze. Furthermore, porous materials have a large specific surface area and pore volume which provide easy contact with the electrolyte, leading to improved catalytic property. In this study, meso-structured lamellar WO3 films have been successfully fabricated by electrodeposition using sodium dodecyl sulfate (SDS) as a templating agent onto indium-tin-oxide-coated (ITO) glasses in a standard three-electrode system using a Pt and Ag/AgCl/KCl (sat’d) electrode as the counter electrode and the reference electrode, respectively. Compared to non-porous WO3 prepared with isopropanol instead of SDS, lamellar phase mesoporous WO3 showed higher photocatalytic activity and greater current density for hydrogen intercalation, probably due to the larger surface area of mesoporous WO3 and more facile charge transport.