Radiocatalytic Cu-incorporated TiO2 nano-particles for the degradation of organic species under gamma irradiation

Abstract

We report on an experimental study aimed at optimizing the radiocatalytic properties of pure and copper-incorporated TiO 2 powders. This has been achieved by conducting crosschecked structural, optical and radiocatalytic studies. Structural and nanoscale analyses show evidence of internal doping by Cu 2+ in the TiO 2 lattice that leads to the reduction of the optical band gap down to 1.5 eV. The effect of gamma radiation on the radiocatalytic activity of these catalysts was studied by degradation of methylene blue as a model pollutant. It was found that the addition of Cu-doped TiO 2 (anatase) powders improves significantly the pollutant degradation, as compared to photocatalysis. The doping and the annealing temperature's impact on the structural, optical and radiocatalytic efficiencies are highlighted and correlated.

Effect of gamma radiation on the photocatalytic properties of Cu doped titania nanoparticles

“…For non-irradiated samples, we note that the intensity of the EPR peak assigned todecreases notably after addition of Cu in the TiO 2 samples [35]. After gamma irradiation such EPR peak increases notably and especially for 3 at.% Cu-TiO 2 , while the 6 at.% Cu-TiO 2 EPR spectrum changes radically.…”

“…4(e)). EPR investigations confirm that the 6 at.% Cu-TiO 2 non-gamma irradiated crystallites are mainly undoped and that copper species are distributed over the surface of the crystallites, in metallic or Cu 2 O forms [35]. Those copper species, by covering the surface of the crystallites, may be at the origin of the photocatalytical efficiency drop by limiting the interaction between the sunlight and the catalyst.…”

“…which is proportional to the absorption coefficient [28].The optical gap value is = [35]. According to experimental and theoretical investigations, the substitution of Cu 2+ for Ti 4+ in anatase (2 at.% Cu-doped TiO 2 ) should lead to a decrease in the band gap, down to 1.7 eV, and an increase in the visible light absorption [26,27].…”

“…At a higher incorporation rate of Cu, segregated copper species are observed on the surfaces of the crystallites. More details concerning the effect of doping on structural and optical properties of Cu-TiO 2 sol-gel powders annealed at 400°C have been presented in our previous work [35].…”

Photocatalytic degradation evaluation of N-Fe codoped aligned TiO2 nanorods based on the effect of annealing temperature

“…Furthermore, they can shift the optical absorption edge of TiO 2 to lower energy, and thereby extend the photoactive region to visible-light [37]. It is well known that the photocatalytic performance of TiO 2 depends strongly on the amount of doping and the annealing temperatures of samples [38]. Therefore, it seems necessary to study the effects of the annealing temperature on the phase structure, crystallinity, specific surface area, and resulting photocatalytic activity of N-Fe codoped TiO 2 nanorods.…”