Synthesis, Characterization, and Photocatalytic, Bactericidal, and Molecular Docking Analysis of Cu–Fe/TiO2 Photocatalysts: Influence of Metallic Impurities and Calcination Temperature on Charge Recombination
Ontology highlight
ABSTRACT:
SUBMITTER: Khan M
PROVIDER: S-EPMC8515581 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:This study reveals a unique Cu-Cu2O@TiO2 heterojunction photocatalyst obtained with metal-organic framework as the precursor, which can be utilized in dye photodegradation under visible light irradiation. The composition, structure, morphology, porosity, optical properties and photocatalytic performance of the obtained catalysts were all investigated in detail. The Cu-Cu2O@TiO2 nanocomposite is composed of lamellar Cu-Cu2O microspheres embedded by numerous TiO2 nanoparticles. Methylene blue, methyl orange and 4-nitrophenol were used as model pollutants to evaluate the photocatalytic activity of the Cu-Cu2O@TiO2 nanocomposite for dye degradation under visible light irradiation. Nearly 95% decolourisation efficiency of Methylene blue was achieved by the Cu-Cu2O@TiO2 photocatalyst within 3 h, which is much higher than that of TiO2 or Cu2O catalysts. The excellent photocatalytic activity was primarily attributed to the unique MOF-based mesoporous structure, the enlarged photo-adsorption range and the efficient separation of the charge carriers in the Cu-Cu2O@TiO2 heterojunction.
| S-EPMC9052089 | biostudies-literature
Project description:TiO2-based powder materials have been widely studied as efficient photocatalysts for water splitting due to their low cost, photo-responsivity, earthly abundance, chemical and thermal stability, etc. In particular, the recent breakthrough of nitrogen-doped TiO2, which enhances the presence of structural defects and dopant impurities at elevated temperatures, exhibits an impressive visible-light absorption for photocatalytic activity. Although their electronic and optical properties have been extensively studied, the structure-activity relationship and photocatalytic mechanism remain ambiguous. Herein, we report an in-depth structural study of rutile, anatase and mixed phases (commercial P25) with and without nitrogen-doping by variable-temperature synchrotron X-ray powder diffraction. We report that an unusual anisotropic thermal expansion of the anatase phase can reveal the intimate relationship between sub-surface oxygen vacancies, nitrogen-doping level and photocatalytic activity. For highly doped anatase, a new cubic titanium oxynitride phase is also identified which provides important information on the fundamental shift in absorption wavelength, leading to excellent photocatalysis using visible light.
| S-EPMC7844033 | biostudies-literature
Project description:Particle attachment and neck formation inside TiO2 nanoparticle networks determine materials performance in sensing, photo-electrochemistry, and catalysis. Nanoparticle necks can feature point defects with potential impact on the separation and recombination of photogenerated charges. Here, we investigated with electron paramagnetic resonance a point defect that traps electrons and predominantly forms in aggregated TiO2 nanoparticle systems. The associated paramagnetic center resonates in the g factor range between g = 2.0018 and 2.0028. Structure characterization and electron paramagnetic resonance data suggest that during materials processing, the paramagnetic electron center accumulates in the region of nanoparticle necks, where O2 adsorption and condensation can occur at cryogenic temperatures. Complementary density functional theory calculations reveal that residual carbon atoms, which potentially originate from synthesis, can substitute oxygen ions in the anionic sublattice, where they trap one or two electrons that mainly localize at the carbon. Their emergence upon particle neck formation is explained by the synthesis- and/or processing-induced particle attachment and aggregation facilitating carbon atom incorporation into the lattice. This study represents a substantial advance in linking dopants, point defects, and their spectroscopic fingerprints to microstructural features of oxide nanomaterials.
| S-EPMC10184168 | biostudies-literature
Project description:Copper-doped TiO2 was prepared with a sol-gel chemical method. Various concentrations (3, 6, and 9 wt%) of Cu dopant were employed. Several techniques were implemented to assess the structural, optical, morphological and chemical properties of the synthesized samples. Evaluation of elemental composition using SEM-EDS and XRF techniques showed the presence of dopant element in the prepared samples. XRD analysis confirmed the presence of anatase (TiO2) phase with interstitial doping. Incorporation of dopant was observed to enhance the crystallinity and increase the crystallite size of the synthesized products. SAED profiles revealed a high degree of crystallinity in the prepared specimens, which was also evident in the XRD spectra. Optical properties studied using UV-vis spectroscopy depicted a shift of the maximum absorption to the visible region (redshift) that signified a reduction in the band gap energy of Cu-doped TiO2 samples. Examination of morphological features with scanning and high-resolution transmission electron microscopes revealed the formation of spherical nanoparticles with a tendency to agglomerate with increasing dopant concentration. Molecular vibrations and the formation of Ti-O-Ti bonds were revealed through FTIR spectra. PL spectroscopy recorded the trapping efficiency and migration of charge carriers, which exhibited electron-hole recombination behavior. Doped nanostructures showed enhanced bactericidal performance and synergism against S. aureus and E. coli. In summary, Cu-doped TiO2 nanostructures were observed to impede bacteria effectively, which is deemed beneficial in overcoming ailments caused by pathogens such as microbial etiologies. Furthermore, molecular docking analysis was conducted to study the interaction of Cu-doped TiO2 nanoparticles with multiple proteins namely β-lactamase (binding score: -4.91 kcal mol-1), ddlB (binding score: -5.67 kcal mol-1) and FabI (binding score: -6.13 kcal mol-1) as possible targets with active site residues. Dye degradation/reduction of control and Cu-doped samples were studied through absorption spectroscopy. The obtained outcomes of the performed experiment indicated that the photocatalytic activity of Cu-TiO2 enhanced with increasing dopant concentration, which is thought to be due to a decreased rate of electron-hole pair recombination. Consequently, it is suggested that Cu-TiO2 can be exploited as an effective candidate for antibacterial and dye degradation applications.
| S-EPMC9055104 | biostudies-literature
Project description:In order to reduce infection risk of novel coronavirus (SARS-CoV-2), we developed nano-photocatalysts with nanoscale rutile TiO2 (4-8 nm) and CuxO (1-2 nm or less). Their extraordinarily small size leads to high dispersity and good optical transparency, besides large active surface area. Those photocatalysts can be applied to white and translucent latex paints. Although Cu2O clusters involved in the paint coating undergo gradual aerobic oxidation in the dark, the oxidized clusters are re-reduced under > 380 nm light. The paint coating inactivated the original and alpha variant of novel coronavirus under irradiation with fluorescent light for 3 h. The photocatalysts greatly suppressed binding ability of the receptor binding domain (RBD) of coronavirus (the original, alpha and delta variants) spike protein to the receptor of human cells. The coating also exhibited antivirus effects on influenza A virus, feline calicivirus, bacteriophage Qβ and bacteriophage M13. The photocatalysts would be applied to practical coatings and lower the risk of coronavirus infection via solid surfaces.
| S-EPMC10000351 | biostudies-literature
Project description:1T-MoS2 is in situ grown on TiO2 nanotubes (TNTs) using a hydrothermal method, forming a 1T-MoS2@TNTs composite, which is confirmed by its physical characterization. The prepared composites show enhanced photocatalytic performance for the degradation of tetracycline hydrochloride under visible light, and the improved photocatalytic activity is closely related to the loaded amount of 1T-MoS2. Therein, 0.5 wt % 1T-MoS2@TNTs can degrade 57% in 1 h, which is the highest photocatalytic efficiency observed in experiments so far. It is speculated that the introduction of 1T-MoS2 may optimize light absorption and charge separation/transport. The active species are identified and the reaction mechanism is proposed here.
| S-EPMC8154240 | biostudies-literature
Project description:Here, we synthesized copper(i) oxide and titanium dioxide nanotubes (TNTs) heterojunctions (HJs) by a photoreduction method using a low-power UV lamp without involving any additional steps, such as chemical reduction, surfactant, or protection agents. Transmission electron microscopy, X-ray diffraction, Raman scattering, X-ray photoelectron spectroscopy, diffuse reflectance spectra, and photoluminescence spectroscopy were carried out to verify the formation of a HJ between the Cu2O nanoparticles (Cu2O NPs) and TNTs. The efficiency and the rate of methylene blue photo-degradation over the Cu2O/TNTs HJ were found to be nearly double and triple compared to the isolated TNTs. The enhanced efficiency is attributed to the narrow band gap and defect states caused by the oxygen vacancies in the vicinity of HJs. Moreover, the type II band alignment of Cu2O NPs and TNTs naturally separates the photo-generated carriers and constrains the recombination process owing to the internal electric field across the Cu2O/TNTs interface.
| S-EPMC9079757 | biostudies-literature
Project description:A novel dot-like Cu2O-loaded TiO2/reduced graphene oxide (rGO) nanoheterojunction was synthesized via UV light reduction for the first time. Cu2O with size of ca. 5 nm was deposited on rGO sheet and TiO2 nanosheets. The products were characterized by infrared spectroscopy, Raman spectrum, UV-Vis diffuse reflectance spectra, XPS techniques, photoluminescence spectra. The results demonstrated that Cu2O and rGO enhanced the absorption for solar light, separation efficiency of electron-hole pairs, charge shuttle and transfer, and eventually improved photoelectrochemical and photocatalytic performance for contaminants degradation. The reaction time and anion precursor could affect the final copper-containing phase. As extending UV irradiation time, Cu2+ was be first reduced to Cu2O and then transformed to metal Cu. In comparison with CH3COO- (copper acetate), NO3- (copper nitrate) and Cl- (copper chloride), SO42- (copper sulfate) was the optimum for synthesizing pure Cu2O phase.
| S-EPMC5348572 | biostudies-literature
Project description:In this paper, we report a simple, feasible and low-cost method to fabricate self-standing metallic materials using cellulose-based biomass as sacrificial templates. This process involves the impregnation of metallic precursors to the cellulose fibers of biomass templates and the transformation of the precursors to corresponding metals or metal oxides (as well as the removal of the cellulose framework) at an elevated temperature. The structures of the metallic materials as fabricated take the form of architectures of biomass templates (e.g., chromatography paper, medical absorbent cotton, catkins of reed, seed balls of oriental plane, and petals of peach blossom), and the various kinds of metals and metal oxides fabricated with these templates include silver, gold, anatase, cupric oxide, zinc oxide, etc. We have demonstrated photocatalytic and bactericidal applications of such metallic materials, and they should find more applications in electronics, catalysis, energy storage, biomedicine and so on.
| S-EPMC6514999 | biostudies-literature
Project description:Composites of titanium dioxide (TiO2) and reduced graphene oxide (RGO) have proven to be much more effective photocatalysts than TiO2 alone. However, little attention has been paid so far to the chemical structure of TiO2/RGO interfaces and to the role that the unavoidable residual oxygen functional groups of RGO play in the photocatalytic mechanism. In this work, we develop models of TiO2 rutile (110)/RGO interfaces by including a variety of oxygen functional groups known to be present in RGO. Using hybrid density functional theory calculations, we demonstrate that the presence of oxygen functional groups and the formation of interfacial cross-links (Ti-O-C covalent bonds and strong hydrogen bonds between TiO2 and RGO) have a major effect on the electronic properties of RGO and RGO-based composites. The electronic structure changes from semimetallic to semiconducting with an indirect band gap, with the lowest unoccupied band positioned below the TiO2 conduction band and largely localized on RGO oxygen and carbon orbitals, with some contributions of RGO-bonded Ti atoms. We suggest that this RGO-based lowest unoccupied band acts as a photoelectron trap and the indirect nature of the band gap hinders electron-hole recombination. These results can explain the experimentally observed extended lifetimes of photoexcited charge carriers in TiO2/RGO composites and the enhancement of photocatalytic efficiency of these composites.
| S-EPMC7007046 | biostudies-literature