Efficient dual functionality of highly porous nanocomposites based on TiO2 and noble metal particles

Porous nanocomposites based on TiO2 aerogels and Au and, respectively, Ag particles were synthesized and their dual functionality to decontaminate water, via photocatalysis, and to detect low concentrations of pollutants from water, via SERS technique, was evaluated using model pollutants. The apparent photodegradation rate constants of a standard pollutant molecule revealed a considerable improvement of the composites photocatalytic performances (even better than one order of magnitude) in comparison with the commercial product Degussa P25. The essential role of the contact between TiO2 and Au nanoparticles was demonstrated and the potential of all synthesized porous composites for photocatalytic experiments with visible light was pointed out. The lowest concentrations of contaminants adsorbed on the noble metal particles detectable by SERS were found to depend on the composite and pollutant species type and were determined to be between 10−3 and 5 × 10−6 M, and 10−8 and 10−10 M for off and under resonant excitation, respectively. The morphological (BET, pore size distribution, TEM) and structural (Raman, XRD, diffuse reflectance) particularities of the obtained porous composites were also discussed.

Research highlights▶ Synthesis of highly porous composites based on TiO2 and Au and, respectively, Ag particles. ▶ Decontaminate water, via photocatalysis, and detect low concentrations of pollutants from water, via SERS. ▶ The apparent photodegradation rate constants are even better than one order of magnitude in comparison with Degussa P25. ▶ The lowest contaminant concentrations detected by SERS are 10−3 M for thioacetamide and 10−4 M for acrylamide, and between 5 × 10−6 and 10−10 M for dye molecules off and under resonant excitation.