One-pot synthesis of Au/N-TiO2 photocatalysts for environmental applications: Enhancement of dyes and NOx photodegradation

Abstract

Au/N-TiO2 photocatalysts with enhanced photoactivity thanks to nitrogen doping and gold nanoparticles (AuNPs) controlled deposition onto titania have been obtained by means of a simple and innovative one-pot synthesis promoting synergetic activity between these two approaches. The activity of the materials under study was evaluated by methylene blue and NOx degradation tests as models of environmental remediation processes for water purification and air depollution. The use of a deposition-precipitation method employing urea allows obtaining Au/N-TiO2 photocatalysts containing 0.3 at.% of nitrogen and 0.5 wt% of gold. The results obtained confirmed that the presence of both, nitrogen and AuNPs, enhanced the TiO2 photoactivity increasing the photodegradation of the dye and NOx in a factor of 4.5 and 1.7, respectively. In particular, the AuNPs enabled the photoactivity under visible light and improved substantially the selectivity of the NO degradation process. The photocatalysts here proposed maintain their properties as they are integrated into a silica matrix producing a product with potential use for the coating of different substrates, such as building materials for application in urban areas and fabrics or foams for the photocatalytic filters production.