Polyanilines/TiO2 composites as versatile materials for NOx abatement

NOx pollution (NO, NO2) is one of the biggest environmental issues that the world is facing nowadays, due to the dramatic effects on both the environment and human health. NOx pollution is responsible for acid rain, smog, many health concerns and it affects the tropospheric ozone. The scientific and industrial communities are hardly working to reduce NOx emissions into the air and numerous strategies have been developed. Among them, photocatalysis has shown an outstanding potential to fight NOx pollution [1]. TiO2 is one of the most investigated semiconductors in this field, thanks to its chemical stability, wide availability and low cost, [2, 3]. However, even though TiO2 is highly active under UV light irradiation, its activity under sunlight is very low [1] and in the dark it is completely inactive. Polyaniline (PANI), one of the main exponent of the class of conducting polymers, could represent an important alternative. In fact, thanks to its redox properties, related to the presence of imino-quinoid/amino-benzenoid groups, and to its sorption ability, [4] it can contribute to the NOx abatement even in the dark. In the present study, PANI/TiO2 composites were synthesized by an innovative green UV-assisted procedure, properly characterized, and applied to the NOx abatement under both UV/LED light irradiation and in dark conditions. It was demonstrated that the polymeric component acts reducing the toxic NO2 species in the corresponding non-toxic NO and the polymer modification was also investigated. Both the night-time activity and the photocatalytic properties were optimized accurately dosing the amount of PANI in the final composite. References 1. V. H. Nguyen, B. S. Nguyen, C. W. Huang, T. T. Le, C. C. Nguyen, T. T. N. Le, Q. Van Le. J. Clean. Prod. 2020, 121912. 2. C. L. Bianchi, C. Pirola, E. Selli, S. Biella, J. Hazard. Mater. 2012, 211-212, 203. 3. C. L. Bianchi, G. Cerrato, C. Pirola, F. Galli, V. Capucci, Environ. Sci. Pollut. Res. 2019, 26, 36117. 4. C. Della Pina, M. A. De Gregorio, L. Clerici, P. Dellavedova, E. Falletta, J. Hazard. Mater. 2018, 344, 1.