Band Engineering of Mesoporous TiO2 with Turnable Defects for Visible-Light Hydrogen Generation
Limited light absorption range and low electron transfer efficiency have always been a major problem in semiconductor photocatalysis. here, a defect-rich heterophase junctions TiO2 porous nanostructure was designed and synthesized to improve the low-utilization rate of photoexcited carriers in photocatalysis. Defects are first introduced into titanium dioxide, and co-doping is used to obtain defect-rich materials. At the same time, heterophase junctions TiO2 with anatase and rutile phases was obtained under temperature control, TiO2 phase junction can well improve the interface charge recombination phenomenon. The two synergistically regulate the favorable direction of hydrogen production, improve the carrier separation efficiency, and reduce the band gap from ultraviolet to visible, thereby constructing the most effective defect. Theoretical prediction and empirical characterization indicate that the TiO2 with defects introduced presents a porous structure, and the doped phase exposes the internal defects of the bulk phase of the material to the surface and adjusts the defect position. Experimental results confirmed that the synergistic effect of B and Rh co-doping increases the photocatalytic hydrogen production yield of TiO2 by 10 times. This study provided new insights into photocatalyst defect regulation.