The TiO2 nanoparticles were synthesized by using the similar method. Firstly, the precursor materials were prepared by using electrospray and the PVP amount used was 0.7 g; secondly, the sprayed materials were mixed with ethanol, water, and acetic acid to undergo a strong stirring for more than 2 h; thirdly, the sample was put in an autoclave for hydrothermal reaction at 160◦C for 24 h.