Research On The Synthesis And Applications Of Black TiO₂

Titanium dioxide (TiO2), one of the most studied semiconductors, has been widely used for energy and environment applications due to its low cost, environmental friendliness and high efficiency. However, the practical applications of TiO2 suffer from the huge electronic bandgap and low electrical conductivity. Introducing defects to cause lattice disorder to synthesize black TiO2 with the core/shell structure proves to be effective to improve its electrochemical performance. Traditional methods to synthesize black TiO2 are mostly based on the hydrogenation thermal treatment under high pressure and high temperature condition to transfer white TiO2 to black TiO2. However, this hydrogen method is expensive, which hinders its mass production. Hence, it’s significant to synthesize black TiO2 facilely and inexpensively to expand its practical applications. Here, we have investigated the synthesis of black TiO2 through the solvothermal method and have achieved the tuning of Ti3+defects according to our requirement in electrochemical applications. And the main research contents are as follows:(1)The synthesis of black TiO2 through the F-assisted solvothermal method.Black TiO2 nanocrystals have been successfully synthesized through a facile one-step solvothermal process. Experimentally, TBOT is used as the precursor, n-propanol as the solvent, and HF as the surfactant. The synthesized black TiO2 has a typical crystalline core/disordered shell structure similar to reported black TiO2. In addition, there exists surface and sub-surface Ti3+ simultaneously in black TiO2.(2)Controllable distribution of Ti3+ defects in black TiO2.We have achieved the controllable tuning of Ti3+ defects by adjusting the reaction condition. Hence, we can synthesize defective TiO2 according to our needs in electrochemical applications facilely and economically.(3)The applications of black TiO2 in energy and environment. Based on the controllable tuning of the distribution of Ti3+ defects, we have investigated the effects of different Ti3+ on the photocatalyst and Li-ion batteries and have given out the optimal distribution.