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Respective construction of Type-II and direct Z-scheme heterostructure by selectively depositing CdS on {001} and {101} facets of TiO2 nanosheet with CDots modification: A comprehensive comparison
摘要： Directional deposition has always been a focus issue in the construction of specific heterostructure. Herein, for the first time, we have demonstrated that the CdS could be selectively deposited on {001} or {101} facets of TiO2 nanosheet, and two different charge transfer processes were formed. First, the selective deposition of CdS on {001} facets of TiO2 nanosheet ({001}TiO2/CdS) would form the Type-II heterostructure, which seriously weakened the redox ability of {001}TiO2/CdS and directly resulted in the low photocatalytic performance (4-Chlorophenol (4-CP), 61.92% in 40 min) and serious photocorrosion of CdS. In contrary, the selective deposition of CdS on {101} facets of TiO2 nanosheet ({101}TiO2/CdS) could construct direct Z-scheme heterostructure with significantly increased photocatalytic 4-CP degradation efficiency (96.12%), much higher than pristine TiO2 nanosheet (87.21%). The hybrids were further modified by carbon nanodots (CDots) ({101}TiO2/CdS/CDots) to enhance photocatalytic performance (99.84%). The obtained direct Z-scheme {101}TiO2/CdS/CDots showed excellent stability and anti-photocorrosion ability. The synergistic effect between TiO2 nanosheet, CdS and CDots was expounded through characterization analyses, and the photocatalytic reaction mechanism was proposed in detail. Toxicity assessment authenticated good biocompatibility and low cytotoxicity of {101}TiO2/CdS/CDots. Our discovery was expected to drive great advances in the use of TiO2 nanosheet for environmental remediation.
关键词： Toxicity,Selective CdS deposition,Z-scheme heterostructure,TiO2 nanosheet,Anti-photocorrosion
更新于2025-09-09 09:28:46
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Nanostructured Titanium Dioxide Based on Titanium Alloys: Synthesis and Properties
摘要： Titanium dioxide (TiO2) has provoked a significant amount of scientific and technological interest due to their anticipated impact in the fields of photocatalysis, solar cells, lithium-ion battery electrodes, and biomedical devices. This is particularly apparent in the case of anodization and ion implantation for modifying Ti-based alloys. However, the lack of sufficient solar light absorption and limited hole diffusion significantly affect the performance of TiO2 in photocatalysis. Moreover, the biocompatibility and corrosion resistance of Ti-based biomedical device need to be enhanced to achieve a longer service life. In the present review, the MOx prepared by anodization is described first. Then, the electrolyte parameters during anodization are assessed by comparing various electrolytes including ethylene glycol, glycerol, formamide, and aqueous electrolytes. Additionally, the effects of ion implantation on the surface of Ti-based alloy are outlined. By analyzing the impact on various synthetic method and modification strategies of nanostructured TiO2, the essential elements of suitable in situ doping ratio and ion implantation dose are addressed. Finally, the outlook for anodization and ion implantation for constructing nanostructured TiO2 is discussed, highlighting challenges and key areas for future research and development.
关键词： Anodization,Water Splitting,Biocompatibility,TiO2-Based Ti Alloy,Ion Implantation
更新于2025-09-09 09:28:46
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Insight into Reinforced Photocatalytic Activity of CNT-TiO <sub/>2</sub> nanocomposite for CO <sub/>2</sub> Reduction and Water Splitting
摘要： Using titanium dioxide (TiO2) and its modified forms for photocatalytic reduction of CO2 reduction and production of hydrogen are promising routes for providing solutions to the world energy demand in the foreseeable future. Here, we report the synthesis of a series of efficient, stable TiO2 nanoparticles modified with multi-walled carbon nanotubes (CNT) via a simple, combined sonothermal method followed by a hydrothermal treatment. In comparison to bare TiO2, the synthesized CNT-TiO2 photocatalysts showed improved photocatalytic activities for CO2 reduction under UVA as well as under visible light; and water (H2O) splitting under visible light at ambient temperature and pressure. The 2.0CNT-TiO2 has performed the best for methanol, hydrogen and formic acid production from the reduction of CO2 with yield rates of 2360.0, 3246.1 and 68.5 μmol g-1 h-1 under UVA, respectively. Its potential was further tested under visible light for methanol production, 1520.0 μmol g-1 h-1. Also, the highest rate of hydrogen yield from water splitting was 69.41 μmol g-1 h-1 with 2.0CNT-TiO2 under visible light at pH 2. The primary photocatalytic reactions of CNT-TiO2 composites and their intimate structure were studied computationally. It was demonstrated that the binding of CNT to TiO2 nanoparticles are preferable at (101) surfaces compared to (001) facets. Interaction of CNT with TiO2 results in common orbitals within TiO2 band gap that enables visible light excitation of the CNT-TiO2 composites can lead to charge transfer between TiO2 and CNT; while UV light excitation can result in charge transfer in any direction, from CNT to TiO2 and from TiO2 to CNT. The latter process is operative in the presence of sacrificial electron donor TEOA.
关键词： photocatalytic reduction,CO2 reduction,UVA light,water splitting,visible light,CNT-TiO2 nanocomposite,hydrogen production
更新于2025-09-09 09:28:46
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Fabrication and Performances of Graphene/TiO2 Composites Derived from Graphenes and Titanium(IV) Alkoxide Precursors
摘要： Graphene/TiO2 composites were synthesized by sol-gel technique using titanium(IV) n-butoxide (TNB), titanium(IV) isopropoxide (TIP) and titanium(IV) propoxide (TPP) as different titanium alkoxide precursors. The as-prepared composites were characterized by BET surface area, SEM, XRD, EDX and UV-visible absorption spectroscopy. The samples were evaluated for their photocatalytic activity towards the degradation of methylene blue (MB) under UV irradiation. The results indicated that the sample GTNB had best excellent photocatalytic activity among the three kinds of samples. According to the photocatalytic results, methylene blue removal by a treatment with graphene/TiO2 composites seems to have an excellent removal effect as order of GTIP, GTNB and GTPP composites due to a photolysis of the supported TiO2, the radical reaction and the adsorptivity and absorptivity of the graphene.
关键词： TiO2,Visible light,Graphene,Photocatalytic,TEM
更新于2025-09-09 09:28:46
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Effect of current density and ZnO nano particles influence on the microstructure and mechanical strengthening properties of Zn-TiO<sub align="right">2-ZnO alloys at constant deposition time
摘要： In this work, the effect of current density and particle loading on microstructure and mechanical properties of Zn-TiO2-ZnO nanocomposite produced via electrocodeposition are investigated. The morphological characteristics of the nano-composite coatings were characterised by scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS). Mechanical examination was carried out using Dura scan micro-hardness tester and CERT UMT-2 multi-functional tribological tester. The corrosion properties were evaluated using linear polarisation technique in 3.5% NaCl. The result showed that the coatings exhibited good stability and the quantitative particle loading significantly improved the micro-structural properties of the coating. It is also noticed that the hardness performance and corrosion resistance of the coatings were significantly impacted with over 70% improvement as against the as-received samples.
关键词： Zn-TiO2-ZnO,electrocodeposition,coatings,corrosion resistance,nanocomposite
更新于2025-09-09 09:28:46
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Novel anti-ultraviolet performances of thin films polyurethane containing nano-mixed oxides CeO <sub/>2</sub> -TiO <sub/>2</sub>
摘要： The nano-mixed oxides CeO2-TiO2 was synthesized by gel combustion method using polyvinyl alcohol as fuel and mixtures of titanium trichloride and cerium(IV) nitrate at a relatively low calcination temperature of 550°C for 2 h. The prepared CeO2-TiO2 nanoparticles with a specific area of 65.70 m2 g-1 were dispersed in polyurethane matrix in different concentration conditions from 0.0 to 1.5 wt% to study ultraviolet durability following HONDA HES D 6501-97 standards. After 400 h of testing in the QUV accelerate weathering tester, the thin film containing 1 wt% CeO2-TiO2 nano-mixed oxides has presented the noticeable capacity for absorbing ultraviolet light by only 6.8 g.u change in specular gloss at 60° and DE = 3.66 in color difference.
关键词： hybrid material,thin film,CeO2-TiO2,nano-mixed oxides,polyurethane,anti-ultraviolet
更新于2025-09-09 09:28:46
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Photoelectrochemical activity of Ag loaded TiO2 nanotube arrays produced by sequential chemical bath deposition for water splitting
摘要： We report on remarkable improvement of photoelectrochemical (PEC) properties of TiO2 nanotubes by loading of Ag nanoparticles into them. The silver nanoparticles were loaded on the nanotubes by sequential chemical bath deposition (S-CBD) with different number of deposition cycles. Various characterizations including field emission scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray analysis (EDX), all confirm that the silver nanoparticles were deposited inside and outside of TiO2 nanotubes. In addition, the PEC properties of the samples were investigated using linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The PEC analyses clearly show that the photoelectrochemical activity of the Ag-loaded samples are considerably higher than the bare TiO2 nanotubes (about 3 times). This mostly originates from the improvement of light absorption due to the plasmonic effects in addition to better separation and transport of electron–hole pairs in the Ag-loaded samples relative to the bare TiO2 nanotubes. All results indicate that the maximum efficiency were obtained for the 8-cycle of S-CBD Ag-loading on the bare TiO2 nanotubes.
关键词： TiO2 nanotubes,sequential chemical bath deposition,water splitting,photoelectrochemical,Ag nanoparticles
更新于2025-09-09 09:28:46
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Dual-Bandgap Effect of Photonic Crystals on TiO2 Photocatalytic Activity in Ultraviolet and Visible Light Regions
摘要： Photonic crystals (PCs) have promising characteristic to raise the light harvest of materials. PCs with one photonic band gap (PBG) were usually used to enhance the light harvest of materials. In this research work, we used PCs with dual PBGs to increase the light harvest. SiO2 PCs with dual PBGs were constructed through depositing a SiO2 PCs layer on another SiO2 PCs layer by vertical deposition method. Then the bi-layer structured SiO2 PCs were composited with nanocrystalline TiO2 film which was sensitized by CdS quantum dots (QDs) (Q-T), to produce photocatalyst for photodegradation of gaseous acetaldehyde. By adjusting the PBGs of the bi-layer SiO2 PCs, namely one PBG matching with the absorption edge of TiO2 and another PBG matching with the absorbing range of CdS QDs, the photocatalytic activity of the composite film under white light irradiation was increased to 2.11 times of that of the control photocatalyst (the Q-T film coated on a disordered porous SiO2 film). When Q-T film was coupled with a monolayer SiO2 PCs, which has single PBG centered at TiO2’s electronic band gap (EBG) of 380 nm, its photocatalytic activity was increased by 1.34 times. When coupled with a monolayer SiO2 PC with the PBG centering at the EBG of CdS QDs (465 nm), the photo-catalytic activity of the Q-T film was increased by 1.54 times. Because the SiO2 PCs with dual-PBGs can simultaneously enhance the light harvest in ultraviolet and visible light region, the Q-T film coupled with dual-PBGs SiO2 PCs showed the highest activity.
关键词： Photocatalyst,SiO2 Opal,Dual photonic band gaps,TiO2,Photonic crystals
更新于2025-09-09 09:28:46
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Synthesis and applications of nano-TiO2: a review
摘要： TiO2-based nanomaterials have attracted prodigious attention as a photocatalysts in numerous fields of applications. In this thematic issue, the mechanism behind the photocatalytic activity of nano-TiO2 as well as the critical properties have been reviewed in details. The synthesis routes and the variables that affect the size and crystallinity of nano-TiO2 have also been discussed in detail. Moreover, a newly emerged class of color TiO2, TiO2 in aerogel form, nanotubes form, doped and undoped form, and other forms of TiO2 have been discussed in details. Photocatalytic and photovoltaic applications and the type of nano-TiO2 that is more suitable for these applications have been discussed in this review.
关键词： Nanocomposites,Photocatalysis,Photovoltaic,Nano-TiO2,DSSC
更新于2025-09-09 09:28:46
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Adsorption mechanism of typical oxygen, sulfur, and chlorine containing VOCs on TiO2 (0?0?1) surface: First principle calculations
摘要： The photocatalytic degradation of volatile organic compounds has been gaining much interest in recent years to solve the long-standing problem of indoor air pollution. For this purpose, anatase TiO2 and its derivatives are regarded as potential photocatalyst materials. Thus, we study the adsorption mechanism of selected volatile organic compounds such as formaldehyde, methyl chloride, and carbon disulfide on TiO2 (0 0 1) surface using first principle calculations to comprehend their surface interaction and catalytic degradation in depth. The study suggests that formaldehyde interacts with TiO2 (0 0 1) surface through chemical bonds that form a saddle-like structure exhibiting a high adsorption energy value (0.543 eV). It can be inferred that the fivefold coordinated Ti5c and twofold coordinated O2c atoms are the only adsorption sites on TiO2 (0 0 1) surface. However, significant variations are observed for chloride and sulfur containing groups. For instance, the methyl chloride and carbon disulfide physisorbed on the surface of TiO2 (0 0 1) without any chemical bond formation exhibits low adsorption energy values. The results are further confirmed by calculating the corresponding density of states, and electron density differences in all cases. This study provides a detailed investigation of various VOCs on the surface of TiO2 (0 0 1), which provides further insight into the construction of photocatalytic materials for the photodegradation of VOCs.
关键词： Methyl chloride,TiO2 (0 0 1) surface,Formaldehyde,VOCs,DFT
更新于2025-09-09 09:28:46