Photohole Induced Corrosion of Titanium Dioxide: Mechanism and Solutions

• DOI: 10.1021/acs.nanolett.5b03114
• Publication Date: 2015-10-01T21:04:19Z
• Authors: Yi Yang; Yichuan Ling; Gongming Wang; Tianyu Liu; Fuxin Wang; Teng Zhai; Yexiang Tong; Yat Li
• Keywords: Titanium Dioxide

Titanium dioxide (TiO2) has been extensively investigated as photoanode for water oxidation, it is believed to be one of the most stable materials. Yet, we surprisingly found that TiO2 photoanodes (rutile nanowire, anatase nanotube, and P25 nanoparticle film) suffered from substantial photocurrent decay in neutral (Na2SO4) well basic (KOH) electrolyte solution. Photoelectrochemical measurements togehter with electron microscopy studies performed on rutile nanowire show due photohole induced corrosion, which competes oxidation reaction. Further reveal profile solutions are fundamentally different. Notably, structural reconstruction surface occurs simultaneously corrosion KOH solution resulting formation an amorphous layer titanium hydroxide, slows down photocorrosion. Based this discovery, demonstrate photoelectrochemical stability can significantly improved by intentionally coating hydroxide surface. The pretreated photaonode exhibits excellent retention rate 97% after testing 72 h, while comparison untreated sample lost 10-20% 12 h under same measurement conditions. This work provides new insights understanding bare photoanodes.