In-situ creating elastic lattice OO bonds over semicrystalline yellow TiO2 nanoparticles for significantly enhanced photocatalytic H2 production

Atomic defects (e.g., Ti 3+ , oxygen vacancies) have been intenstively investigated for modifying TiO 2 in order to reach visible light active photocatalytic H 2 production. However, the atomic defects within TiO 2 could easily act as photo-generated charge-carrier recombination centers, resulting in relatively low H 2 conversion efficiency. In this paper, semicrystalline yellow TiO 2 nanoparticles rich of superoxide ions are new synthesized by a simple aqueous solution method. Instead of introducing atomic defects, we show for the first time that catalytic performance can also be significantly improved via in-situ creating lattice O O bonds within metastable semicrystalline TiO 2 . The synthesized semicrystalline yellow TiO 2 exhibits significantly enhanced photocatalytic activity for H 2 production after cycle tests. The formaldehyde in aqueous solution is used as target pollutant to simulate industrial wastewater. In-situ created elastic lattice O O bonds are proposed to improve catalytic performance through facilitating the breakage of C H bonds of HCHO. A series of internally consistent reaction equations is proposed that describes the role of in-situ created lattice O O bonds for improving the catalytic performance. This is strongly supported by that the H 2 production rate at the end of the fourth cycle test is significantly more than that of the beginning of the first cycle test.