Atomic defects (e.g., Ti3+, oxygen vacancies) have been intenstively investigated for modifying TiO2 in order to reach visible light active photocatalytic H-2 production. However, the atomic defects within TiO2 could easily act as photo-generated charge-carrier recombination centers, resulting in relatively low H-2 conversion efficiency. In this paper, semicrystalline yellow TiO2 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 TiO2 . The synthesized semicrystalline yellow TiO2 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.