In situ preparation of PDA decorated Ag/black mesoporous TiO2 nanocomposites for photocatalytic and antibacterial applications

Driven by clean solar energy, photocatalytic technology can effectively degrade organic pollutants and kills pathogenic bacteria. Researchers are always devoted to developing more economical and efficient photocatalysts. In this work, mesoporous TiO2 nanoparticles (MTN) with controlled diameters (100–200 nm) and large specific surface areas (∼112 m2/g) were prepared via a simple sol–gel method. Then, 10 wt% Ag nanocrystals (∼5 nm) were in situ generated in the MTN via solvothermal process, Ti3+ and oxygen vacancies also been introduced on their surface, thereby leading to a narrowed bandgap (∼2.9 eV) and strong absorption in the visible region. Finally, polydopamine (PDA) was decorated on the surface of Ag/bMTN to further improve their dispersity and photocatalytic activity. The degradation rate of tetracycline and the bactericide rate of E. coli could surpass 90 % and 99 %, which were mainly attributed to the generated O2− and the released Ag ions.