WO3/TiO2 core–shell nanostructure for high performance energy-saving smart windows

Abstract

The electrochromic, photodegradation, and photoinduced hydrophilicity properties of the WO3/TiO2 core–shell nanostructure as a smart building material for energy-saving are investigated. The core–shell nanostructure exhibits a highly reduced ion intercalation capacity with good reversible electrochemical cycling of intercalation–deintercalation, and shows a higher coloration efficiency (110.8cm2C−1), faster switching speed (0.7s and 2.9s) and better cycling performance than as-deposited WO3 nanowires (NWs). The TiO2 shell layer greatly enhanced the photocatalytic oxidation activity of WO3 NWs, increasing the photoinduced hydrophilic conversion. The enhanced photocatalytic reaction by the core–shell structure was attributed to the multi-electron reduction in the interlayer, caused by the electrons injected from the conduction band of the WO3 NWs. These results suggest that the WO3/TiO2 core–shell nanostructure enhances the electrochromic, photodegradation, and photoinduced hydrophilicity properties due to the increased density of charge separated electron–hole pairs aided by the TiO2 and WO3 interlayer. The WO3/TiO2 core–shell structure was found to possess superior properties giving it good potential for use in energy-saving smart windows.