Efficient N, Fe Co-Doped TiO2 Active under Cost-Effective Visible LED Light: From Powders to Films

Abstract

An eco-friendly photocatalytic coating, active under a cost-effective near-visible LED system, was synthesized without any calcination step for the removal of organic pollutants. Three types of doping (Fe, N and Fe + N), with different dopant/Ti molar ratios, were investigated and compared with undoped TiO2 and the commercial P25 photocatalyst. Nano-crystalline anatase-brookite particles were successfully produced with the aqueous sol-gel process, also at a larger scale. All samples displayed a higher visible absorption and specific surface area than P25. Photoactivity of the catalyst powders was evaluated through the degradation of p-nitrophenol in water under visible light (>400 nm). As intended, all samples were more performant than P25. The N-doping, the Fe-doping and their combination promoted the activity under visible light. Films, coated on three different substrates, were then compared. Finally, the photoactivity of a film, produced from the optimal N-Fe co-doped colloid, was evaluated on the degradation of (i) p-nitrophenol under UV-A light (365 nm) and (ii) rhodamine B under LED visible light (395 nm), and compared to undoped TiO2 film. The higher enhancement is obtained under the longer wavelength (395 nm). The possibility of producing photocatalytic films without any calcination step and active under low-energy LED light constitutes a step forward for an industrial development.

Green Synthesis of N/Zr Co-Doped TiO2 for Photocatalytic Degradation of p-Nitrophenol in Wastewater

“…For all samples, Figure 8 shows the photocatalytic degradation of PNP under UV/visible light after 8 h of illumination. In the dark, no adsorption of PNP on the samples occurred, as observed in previous studies [14,27,61]. All doped and co-doped samples showed a higher degradation efficiency than pure TiO 2 sample.…”

“…Nevertheless, the photoactivity of the samples with N doping (Figures 8 and 9) increases with the doping, showing that the samples are different. It may be possible that the repartition of nitrogen is not homogeneous along the samples and, as previously observed [60,61], that some nitrogen signals are not detected by XPS as it is a surface analysis. As the photocatalysts are illuminated by UV light, the N doping has a slight influence on the PNP degradation activity.…”

Deposition of Hybrid Photocatalytic Layers for Air Purification Using Commercial TiO2 Powders

“…This visible light absorption can be beneficial for visible light photocatalysis. It is common to try to increase the sensitivity of TiO 2 photocatalysts to visible light by doping with N or Fe [14]; Cu, Ni, Zn, or Pb [15], ZrO 2 [16]; and V, Nb, or Ta [17]. However, it is rare to find such doped photocatalysts in commercial nanopowders.…”

Natural Clay Modified with ZnO/TiO2 to Enhance Pollutant Removal from Water

“…AOPs can be used either as an oxidative pretreatment leading to easily biodegradable compounds, or as a tertiary treatment method for the removal or complete mineralization of residual pollutants [15]. This process is based on the generation of radical species able to degrade organic pollutants thanks to the use of a photocatalyst material activated by UV radiation [16]. The most-used UV-sensitive photocatalysts are TiO 2 and ZnO [17][18][19].…”