“…UV–Vis diffuse reflectance spectrum is an efficient means to detect the presence of framework- and non-framework-incorporated transition metal species in crystal structures, thus distinguishing the coordination states of the elements and measuring the optical properties of solid powders. 32,35 To provide insight into the effect of W, Bi and S on optical property of TiO 2 , the UV–Vis DRS spectra of W–Bi–S-tridoped TiO 2 were investigated and are shown in Fig. 4.…”
Section: Resultsmentioning
confidence: 99%
“…36 This behaviour may be explained by the synergistic effect of W, Bi and S. And the cooperative effect of anion–cation had a strong mutual structural influence on the band structure, and hence changed the band gap value eventually. 35 In terms of W–Bi–S-tridoped TiO 2 , the improvement in the absorption properties was much more pronounced, thus the number of photogenerated electrons and holes to participate in the photocatalytic reaction would be even more and further enhanced the photocatalytic activity of TiO 2 ultimately. 4 UV–Vis diffuse reflectance spectra of the samples calcined at 500°C…”
In the present work, W–Bi–S-tridoped TiO2 nanoparticles were synthesised by a simple sol–gel method. The structure and morphology of as-prepared W–Bi–S-tridoped TiO2 were characterised by using X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy and UV–Vis diffuse reflectance spectrum. It was found that the W–Bi–S-tridoped TiO2 nanoparticles were well crystallised with a small size distribution. The absorption edge of TiO2 was extended into visible-light region obviously after being doped with W, Bi and S. The photocatalytic degradation of methylene blue was used as a probe reaction to evaluate the efficiency of W, Bi and S doping. The W–Bi–S-tridoped TiO2 exhibited the best photocatalytic activity, compared with TiO2, S-TiO2, W–S–TiO2 and Bi–S–TiO2. The mechanism that enhanced photocatalytic activity might be attributed to the synergistic effect of W, Bi and S.
“…UV–Vis diffuse reflectance spectrum is an efficient means to detect the presence of framework- and non-framework-incorporated transition metal species in crystal structures, thus distinguishing the coordination states of the elements and measuring the optical properties of solid powders. 32,35 To provide insight into the effect of W, Bi and S on optical property of TiO 2 , the UV–Vis DRS spectra of W–Bi–S-tridoped TiO 2 were investigated and are shown in Fig. 4.…”
Section: Resultsmentioning
confidence: 99%
“…36 This behaviour may be explained by the synergistic effect of W, Bi and S. And the cooperative effect of anion–cation had a strong mutual structural influence on the band structure, and hence changed the band gap value eventually. 35 In terms of W–Bi–S-tridoped TiO 2 , the improvement in the absorption properties was much more pronounced, thus the number of photogenerated electrons and holes to participate in the photocatalytic reaction would be even more and further enhanced the photocatalytic activity of TiO 2 ultimately. 4 UV–Vis diffuse reflectance spectra of the samples calcined at 500°C…”
In the present work, W–Bi–S-tridoped TiO2 nanoparticles were synthesised by a simple sol–gel method. The structure and morphology of as-prepared W–Bi–S-tridoped TiO2 were characterised by using X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy and UV–Vis diffuse reflectance spectrum. It was found that the W–Bi–S-tridoped TiO2 nanoparticles were well crystallised with a small size distribution. The absorption edge of TiO2 was extended into visible-light region obviously after being doped with W, Bi and S. The photocatalytic degradation of methylene blue was used as a probe reaction to evaluate the efficiency of W, Bi and S doping. The W–Bi–S-tridoped TiO2 exhibited the best photocatalytic activity, compared with TiO2, S-TiO2, W–S–TiO2 and Bi–S–TiO2. The mechanism that enhanced photocatalytic activity might be attributed to the synergistic effect of W, Bi and S.
“…Many studies investigated the effect of (1) semiconductor type such as TiO 2 , ZnO, and SnO 2 [9,10]; (2) the number (mono-, bi-, or tri-doping) and the ratio of doping agents (N, P, Fe, Ag, etc.) [11,12,13,14]; (3) the support type such as polyester, cellulose, polypropylene, or polystyrene [15,16,17]; and (4) the substrate functional groups before the catalyst deposition [18,19]. It had been widely reported that band gap energy, surface area, particles size, and chemical stability were the most important parameters controlling the reactivity of a photocatalytic material [20,21,22].…”
In the present study, we propose a new photocatalytic interface prepared by high-power impulse magnetron sputtering (HiPIMS), and investigated for the degradation of Reactive Green 12 (RG12) as target contaminant under visible light light-emitting diodes (LEDs) illumination. The CuxO/TiO2 nanoparticulate photocatalyst was sequentially sputtered on polyester (PES). The photocatalyst formulation was optimized by investigating the effect of different parameters such as the sputtering time of CuxO, the applied current, and the deposition mode (direct current magnetron sputtering, DCMS or HiPIMS). The results showed that the fastest RG12 degradation was obtained on CuxO/TiO2 sample prepared at 40 A in HiPIMS mode. The better discoloration efficiency of 53.4% within 360 min was found in 4 mg/L of RG12 initial concentration and 0.05% Cuwt/PESwt as determined by X-ray fluorescence. All the prepared samples contained a TiO2 under-layer with 0.02% Tiwt/PESwt. By transmission electron microscopy (TEM), both layers were seen uniformly distributed on the PES fibers. The effect of the surface area to volume (dye volume) ratio (SA/V) on the photocatalytic efficiency was also investigated for the discoloration of 4 mg/L RG12. The effect of the presence of different chemicals (scavengers, oxidant or mineral pollution or salts) in the photocatalytic medium was studied. The optimization of the amount of added hydrogen peroxide (H2O2) and potassium persulfate (K2S2O8) was also investigated in detail. Both, H2O2 and K2S2O8 drastically affected the discoloration efficiency up to 7 and 6 times in reaction rate constants, respectively. Nevertheless, the presence of Cu (metallic nanoparticles) and NaCl salt inhibited the reaction rate of RG12 discoloration by about 4 and 2 times, respectively. Moreover, the systematic study of reactive oxygen species’ (ROS) contribution was also explored with the help of iso-propanol, methanol, and potassium dichromate as •OH radicals, holes (h+), and superoxide ion-scavengers, respectively. Scavenging results showed that O2− played a primary role in RG12 removal; however, •OH radicals’ and photo-generated holes’ (h+) contributions were minimal. The CuxO/TiO2 photocatalyst was found to have a good reusability and stability up to 21 cycles. Ions’ release was quantified by means of inductively coupled plasma mass spectrometry (ICP-MS) showing low Cu-ions’ release.
N‐Doped TiO2 coatings (N‐TiO2) were synthesized and characterized. The effect of the doping process on the physical‐chemical properties and photocatalytic efficiency of Methylene Blue (MB) under visible light irradiation were studied. The bare TiO2 showed only anatase crystalline structure. Furthermore, after the doping process, a slight transition from anatase to rutile was verified. The HRXPS confirmed that the doping process was effective. The N2 sorption using the BET assay showed a slight increase in surface area after the doping process. MB adsorption kinetic showed also a slight increase for doped TiO2 films, showing as best fitting the Langmuir model. Furthermore, a modification on the electronic structure was observed, showed by the modification of the optical absorption profile in the doped material. The results showed that the MB adsorption on N‐TiO2 thin films was endothermic (▵H=11 kJ mol−1) and a spontaneous process (▵G=−6.45 kJ mol−1). We performed DFT calculations to three simulated doped‐structures. The Gap value, the global reactivity indexes and, the Fukui function isosurfaces are presented. Finally, the scavenger tests suggested that
and OH⋅ could be the main ROS driving the photocatalytic process.
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