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XPS valence band spectra of (a) P-TiO 2 , (b) RP-TiO 2 -12 h, and (c) schematic diagram of the DOS of RP-TiO 2 -12 h and P-TiO 2 .
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This paper reports that the introduction of elemental red phosphorus (RP) into TiO2 can shift the light absorption ability from the UV to the visible region, and confirmed that the optimal RP loading and milling time can effectively improve the visible light driven-photocatalytic activity of TiO2. The resulting RP-TiO2 nanohybrids were characterize...
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... gain greater insight into the band gap reduction and improved photophysical properties of the RP-TiO 2 -12 h nanohybrid, the density of states (DOS) was determined from the UV-visible diffuse absorp- tion results (Figure 4a-c) and valance band (VB) XP spectra ( Figure 5). To obtain more insight and better understanding of the band gap narrowing phenomenon in RP-TiO 2 -12 h, valence band XPS was performed and density of electronic states of RP-TiO 2 -12 h and P-TiO 2 was also obtained based on the VB XPS results and visible diffuse absorption spectroscopy results. ...
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... obtain more insight and better understanding of the band gap narrowing phenomenon in RP-TiO 2 -12 h, valence band XPS was performed and density of electronic states of RP-TiO 2 -12 h and P-TiO 2 was also obtained based on the VB XPS results and visible diffuse absorption spectroscopy results. P-TiO 2 showed valence band DOS characteristics with the edge of the maximum energy at approximately 2.5 eV (Figure 5a), which is similar to previous reports, whereas the valence band maximum energy of RP-TiO 2 -12 h was estimated to be 1.99 eV followed by a band tail at ~0.71 eV ( Figure 5b) 21,22 . The optical band gap energy of the P-TiO 2 and RP-TiO 2 -12 h are 3.2 eV and 2.5 eV, respectively. ...
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... obtain more insight and better understanding of the band gap narrowing phenomenon in RP-TiO 2 -12 h, valence band XPS was performed and density of electronic states of RP-TiO 2 -12 h and P-TiO 2 was also obtained based on the VB XPS results and visible diffuse absorption spectroscopy results. P-TiO 2 showed valence band DOS characteristics with the edge of the maximum energy at approximately 2.5 eV (Figure 5a), which is similar to previous reports, whereas the valence band maximum energy of RP-TiO 2 -12 h was estimated to be 1.99 eV followed by a band tail at ~0.71 eV ( Figure 5b) 21,22 . The optical band gap energy of the P-TiO 2 and RP-TiO 2 -12 h are 3.2 eV and 2.5 eV, respectively. ...
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... decrease in band gap in this study may be due to the displacement and/or substitution of phosphorus in the TiO 2 lattice system. Figure 5c presents a schematic diagram of the DOS, which is proposed based on the combined results of the UV-visible diffuse absorption and VB XPS results. The valence band tail may extend above the valence band maxima or the up lifting of the valence band maxima, which might be responsible for the optical absorption onset in RP-TiO 2 -12 h 21,22 . ...
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... chemical nature and elemental binding in RP-TiO 2 -12 h was investigated by XPS and compared with that of P-TiO 2 . The general scan spectra revealed the presence of Ti 2p, O 1 s, P 2p in the RP-TiO 2 -12 h nano- hybrid ( Figure S5). The high resolution spectra of the Ti 2p electron showed the two main peaks located at a binding energy (BE) of 458.76 ± 0.01 and 464.01 ± 0.01 eV for P-TiO 2 , and 459.01 ± 0.01 and 464.8 ± 0.01 eV for RP-TiO 2 -12 h, which were assigned to Ti 2p 3/2 and Ti 2p 1/2 of TiO 2 , respectively (Figure 6a). ...
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An excellent ternary composite photocatalyst consisting of silver orthophosphate (Ag3PO4), attapulgite (ATP), and TiO2 was synthesized, in which heterojunction was formed between dissimilar semiconductors to promote the separation of photo-generated charges. The ATP/TiO2/Ag3PO4 composite was characterized by SEM, XRD, and UV-vis diffuse reflectance...
Citations
... Transforming TiO 2 's optical response from the ultraviolet to the visible light area can greatly enhance the material's photocatalytic activity. The visible light response of TiO 2 's photocatalytic activity can be effectively enhanced by doping the material with foreign ions, which may be metals, non-metals 22,23 and rare earth metals 24 . Changing out the oxygen or Ti +4 atoms with foreign ions with comparable ionic radii allowed for this enhancement to happen. ...
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... Diffused reflectance spectroscopy confirmed the nanoscale and absorbance range of AgNPs [51][52][53] and ZnO NPs [54][55][56]. The absorbance shifts toward a longer wavelength confirmed the successful conjugation of the Neo drug to Ag/ZnO NC [57]. The agglomeration of NPs with the antibiotic, as well as the decrease in the energy gap between the excited state and the ground state, might be the reason for this red shift in UV [58]. ...
Multidrug-resistant wound infections are a global health threat and a leading cause of death, persisting despite available treatments due to antibiotic resistance, biofilms, and ineffective drug delivery systems. The aim of this study is to (i) formulate an innovative nano-drug delivery system (NDDS) based on a Carbopol nanoemulgel (NEG) co-loaded with neomycin-silver/zinc oxide nanocomposite (NC) that could fight clinical MDR and treat biofilm-forming wound pathogens through topical application, and (ii) assess its in vivo wound-healing potential. The silver/zinc oxide (Ag/ZnO) NC was synthesized by co-inoculating the metabolites of Aspergillus welwitschiae and Meyerozyma guilliermondii. The synthesized NC was then conjugated with neomycin and loaded into a Carbopol NEG for efficient topical delivery. The resulting Neo-Ag/ZnO NEG was characterized physicochemically (e.g., UV-visible [UV-Vis] spectrophotometry, field emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared [FTIR] spectroscopy), biologically (e.g., in vitro antimicrobial, antibiofilm, and hemolytic activities), and pharmacologically (e.g., drug content, ex vivo drug release behavior, and in vivo wound-healing potential). The physicochemical analysis confirmed the successful mycosynthesis of the Carbopol NEG-loaded Neo-Ag/ZnO NC. SEM depicted a crystalline polyhedral shape of the small NC (average particle size of 38 nm). FTIR studies showed a slight interaction with the drug and other bioactive moieties in the Carbopol NEG. The Neo content in the Carbopol NEG was as high as 98%, and a maximum release of 81% for Neo, Ag, and ZnO ions was noticed after 12 h. The NDDS appeared hemocompatible and displayed a minimal inhibition concentration of 0.002 µg/mL with the greatest antimicrobial potential against S. aureus (an inhibition zone of 46 mm) compared to other tested wound microbes (p < 0.05). Statistically significant wound-healing activity was found for NDDS (p = 0.0001) in comparison to the control at a concentration of 100 mg/mL. The results showed that this newly developed Carbopol NEG-loaded neo-Ag/ZnO NC appeared promising for controlling resistant skin infections and boosting wound regeneration.
... Various semiconductor nanomaterials such as TiO 2 , CuO, WO 3 , ZnO, MoO 3 , and SnO 2 have been studied as photocatalysts for the degradation of a wide spectrum of pollutants owing to their suitable physicochemical properties [11,12]. Among these metal oxides, TiO 2 is one of the most widely investigated as it is non-toxic, stable, easily available, and lowcost [13][14][15]. However, the high band gap (3.2 eV) of anatase TiO 2 and the high recombination rate of its charge carriers result in low photosensitivity in the wider solar spectrum [13]. ...
... Among these metal oxides, TiO 2 is one of the most widely investigated as it is non-toxic, stable, easily available, and lowcost [13][14][15]. However, the high band gap (3.2 eV) of anatase TiO 2 and the high recombination rate of its charge carriers result in low photosensitivity in the wider solar spectrum [13]. Molybdenum trioxide (MoO 3 ) is also a fascinating metal oxide semiconductor characterized by non-toxicity, low cost, and high electrochemical activity [16]. ...
In this work, for the first time, the MoO 3 /TiO 2 /rGO nanocomposites with different weight ratios of rGO (0%, 5%, 10%, and 20%) were fabricated using pulsed laser ablation technique. The as-fabricated nanocomposites were employed for photodegradation of Methylene Blue (MB) under UV light irradiation. The morphological, structural , and chemical properties of the fabricated photocatalysts were characterized using XRD, TEM, SEM, UV-DRS, XPS, FTIR, TGA, DSC, and PL. Comparative experimental studies displayed that MoO 3 /TiO 2 /rGO nano-composites fabricated with 5% rGO showed the highest photocatalytic degradation (95%) of MB under UV irradiation. This superior photocatalytic performance could be ascribed to the narrow bandgap of the fabricated nanocomposites as well as the synergistic effect of the three components.
... The valence band of pristine TiO 2 and TiCl 4 treated TiO 2 is determined by a linear extrapolation of the initial onset of XPS spectra, see figure S4. As the binding energy scale is referenced to the Fermi energy level (E f ), the valence band maximum (VBM) values are found to be ∼2.67 and ∼2.41 eV below the E f of TiO 2 and TiO 2-Treated films, respectively; these values are close to those reported [59]. On the other hand, the E f of pristine TiO 2 (−5.01 eV) and TiCl 4 treated TiO 2 (−4.93 eV) films were calculated from Kelvin probe measurements, using the vacuum energy position as a reference. ...
The continuous search for low-cost and environment-friendly materials in photovoltaic applications has become a priority, as well as the understanding of the various strategies to boost the photovoltaic performance. In this work, we investigate the effect of TiCl4 treatment on a compact TiO2 layer used as an electron transport material (ETM) in Sb2S3 planar solar cells. After TiCl4 treatment, TiO2 exhibits higher crystallinity, lower density of hydroxyl groups acting as traps, and better surface coverage of the FTO substrate. Although no major structural changes are observed in Sb2S3 films grown on pristine or TiCl4 treated TiO2 films, there are differences in preferential growth of Sb2S3 (hk1) planes, sulfur-enrichment of the chalcogenide film, and superior substrate coverage after the TiCl4 treatment, leading to the decrease of interfacial trap states. The driving force for electron injection in the TiO2/Sb2S3 heterojunction is also favored by the shift on the VB and CB positions of TiCl4 treated TiO2. These findings are in agreement with the improved power conversion efficiency of the planar solar cell FTO/TiO2-Treated/Sb2S3/SbCl3/spiro-OMeTAD/Au.
... A last check has been dedicated at the valence band peak, to observe if the introduction of N and Fe atoms has modified somehow the region, which represents the experimental counterpart of the theoretical DOS (Density of States). First of all, the shape of both curves (Fig. 5f) is like the one reported in the literature for pure titania [38]. So we calculated the Valence Band Maximum (VBM) position, referred to the Fermi Level (E F = 0 eV), by means of a linear curve fit in the descending portion of the signal, towards 0 eV. ...
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... and PANI-TiO 2 binary composites (20.4-54.4%). This could be accounted on the irradiation in the visible light region that has restricted the photocatalytic activity of TiO 2 due to its wide band gap of 3.28 eV [52]. ...
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Photocatalysed degradation of environmental contaminants is one of the most fashionable technologies in the purification of water because the method converts toxic products to nontoxic ones. In this study, a method has been developed to synthesize novel nanocomposites of Na-Ca-Al-Si oxides for the first time. The average surface area, pore volume and pore size for the novel product were 1742.55 m²/g, 0.3499 cc/g and 3.197 nm respectively. The crystal parameters were a = 7.1580 Å, b = 7.4520 Å, c = 7.7160 Å, α = 115.0600, β = 107.3220, γ = 100.4380, density (calculated) = 2.0 × 10³g/cm³ and cell volume = 332.7 ų respectively. The average crystalline size deduced from the Scherrer equation (i.e. 6.9393 nm) was higher than the value of 1.024 nm obtained from the graphical method. The FTIR and UV spectra of the nanocomposites were unique and provided baseline information that characterises the new product. XRD profiling of the new product reveals the existent of a silica framework consisting of NaAlSi3O3 and CaAl2Si2O8 The synthesized nanocomposites is an effective photocatalyst for the degradation of methyl orange dye in water, with aoptimum efficiency of 96% at an initial dye concentration of 10 ppm, the adsorbent dosage of 0.5 g,contact time of 90 min and pH of 2.5. The Langmuir-Hinshelwood, modified Freundlich and pseudo-second kinetic models were significant in the description of the photocatalytic kinetics of the degraded dye molecules.
... eV, which is the range of band gaps of semiconductors classified as catalysts that can be used for hydrogen production by photochemical water splitting. 9 It was found that BNNTs with a small excess of boron or carbon substitution can be used as candidates for the preparation of photocatalysts because their optical absorptions are within the spectral range. Nevertheless, the photocatalytic efficiency of the C-or Bsubstituted BNNT for the evolution of H 2 under visible light was not satisfactory. ...
... The pristine unit cell of the armchair single-walled boron nitride nanotubes (SWBNNTs) was optimized from the generated carbon nanotube structure via the Tubegen database. 16 To ensure good stability of the optimized nanotubes, (8,8), (9,9), (10, 10), (11,11), and (12,12) armchair configurations were studied, and the bond lengths were adjusted to the experimental value of 1.71 Å. 17 It was found that only (10, 10) and (12,12) SWBNNTs were stable toward MoS 2 doping. The SWBNNTs were doped by exchanging B and N atoms at appropriate positions. ...
... The pristine unit cell of the armchair single-walled boron nitride nanotubes (SWBNNTs) was optimized from the generated carbon nanotube structure via the Tubegen database. 16 To ensure good stability of the optimized nanotubes, (8,8), (9,9), (10, 10), (11,11), and (12,12) armchair configurations were studied, and the bond lengths were adjusted to the experimental value of 1.71 Å. 17 It was found that only (10, 10) and (12,12) SWBNNTs were stable toward MoS 2 doping. The SWBNNTs were doped by exchanging B and N atoms at appropriate positions. ...
This study investigated the photocatalytic properties of MoS2-doped boron nitride nanotubes (BNNTs) for overall water splitting using popular density functional theory (DFT). Calculations of the structural, mechanical, electronic, and optical properties of the investigated systems were performed using both the generalized gradient approximation and the GW quasi-particle correction methods. In our calculations, it was observed that only (10, 10) and (12, 12) single-walled BNNTs (SWBNNTs) turned out to be stable toward MoS2 doping. Electronic property calculations revealed metallic behavior of (10, 10)-MoS2-doped SWBNNTs, while the band gap of (12, 12) SWBNNT was narrowed to 2.5 eV after MoS2 doping, which is within the obtained band gaps for other photocatalysts. Hence, MoS2 influences the conduction band of pure BNNT and improves its photocatalytic properties. The water-splitting photocatalytic behavior is found in (12, 12) MoS2-doped SWBNNT, which showed higher water oxidation (OH–/O2) and reduction (H⁺/H2) potentials. In addition, optical spectral calculations showed that MoS2-doped SWBNNT had an optical absorption edge of 2.6 eV and a higher absorption in the visible region. All of the studied properties confirmed MoS2-doped SWBNNT as a better candidate for next-generation photocatalysts for hydrogen evolution through the overall water-splitting process.
... Despite having the smallest particle size, lowest photocatalytic activity was obtained in the presence of ZnO commercial due to the higher band gap (3.29 eV) than ZnO-TLR and ZnO-BE samples (3.20 eV). The narrower band gap energy is preferable due to the ease of electron excitation from the valence band to the conduction band, further enhancing the photo response capacity of ZnO (Ansari and Cho, 2016). ...
