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- 2019
- Dye-sensitized solar cell
- Hierarchical structure
- Light scattering
- TiO2 photoanode
- Nanomaterials and Technology
- National Sun Yat-sen University
- Wenzao Ursuline University of Languages
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CuO photoelectrodes synthesized by the sol–gel method for water splitting
摘要： CuO is an attractive photocatalytic material for water splitting due to its high earth abundance and low cost. In this paper, we report the deposition of CuO thin films by sol–gel dip-coating process. Sol deposition has attractive advantages including low-cost solution processing and uniform film formation over large areas with a fairly good control of the film stoichiometry and thickness. Pure CuO phase was obtained for calcination temperatures higher than 360 °C in air. The CuO photocurrents for hydrogen evolution depend on the crystallinity and the microstructure of the film. Values of ?0.94 mA cm?2 at pH = 8 and 0 V vs. RHE were achieved for CuO photoelectrodes annealed at 400 °C under air. More interestingly, the stability of the photoelectrode was enhanced upon the sol–gel deposition of a TiO2 protective layer. In this all sol–gel CuO/TiO2 photocathode, a photocurrent of ?0.5 mA cm?2 is achieved at pH = 7 and 0 V vs. RHE with a stability of ~100% over 600 s.
关键词： TiO2 protecting layer for CuO photoelectrode,Sol–gel,CuO photoelectrode,Water splitting
更新于2025-09-04 15:30:14
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UV light-induced photocatalytic, antimicrobial, and antibiofilm performance of anodic TiO2 nanotube layers prepared on titanium mesh and Ti sputtered on silicon
摘要： The potential use of TiO2 nanotube layers as a self-sterilizing and self-cleaning material for environmental application is presented. Antimicrobial, antibiofilm and photocatalytic performance of anodic TiO2 nanotube layers under UV irradiation was investigated on titanium mesh and on Ti sputtered on silicon substrates. The nanotubes were prepared in fluoride containing ethylene glycol-based electrolyte to obtain ~ 4 μm thick nanotube layers, which were subsequently annealed at 450 °C. Structural and morphological properties of prepared TiO2 layers were characterized using X-ray diffraction, scanning electron microscopy and atomic force microscopy. In addition, their surface wettability, before and after UV irradiation, was investigated. Their photoactivity was compared to TiO2 sol–gel films of similar thickness. The highest efficiency in photocatalytic degradation of organic dye and removal of free-floating bacteria of Gram-positive Staphylococcus epidermidis was observed for TiO2 nanotube layers on titanium mesh. The highest antibiofilm performance in impairments of biofilms was reached using the TiO2 nanotubes on silicon. The obtained results on silicon substrate are promising for the development of medical devices covered by TiO2 nanotubes that would decrease the risk of infection. On the other hand, the mesh substrate covered by TiO2 nanotubes could find environmental applications such as filters in flowing photocatalytic reactors.
关键词： Nanotubes,TiO2,Antibiofilm,Photocatalytic,Antimicrobial
更新于2025-09-04 15:30:14
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Sulfated TiO2/WO3 nanocomposite: An efficient photocatalyst for degradation of Congo red and methyl red dyes under visible light irradiation
摘要： TiO2/WO3 nanocomposites (NCs) were successfully prepared by ultrasonic-assisted sol-gel method and acid functionalized (sulfated) by using chlorosulfonic acid. Various physicochemical properties of as prepared NCs were studied by using X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy with energy dispersive analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, UV visible diffused reflectance spectroscopy, and Brunauer-Emmett-Teller (BET) surface area analysis. It was confirmed that the active sulfonic groups are anchored onto the surface of binary NCs. Furthermore, the photocatalytic performance of this material was significantly higher for the degradation of Congo red and methyl red dyes. Both these azo dyes were degraded only within 120 min. under visible light irradiation. Recyclability of this catalyst was also studied and it was found that even after five consecutive cycles the introduced catalyst retain its catalytic efficiency above 90 %.
关键词： Photocatalysis,Sulfated TiO2/WO3,Methyl red,Nanocomposites,Congo red
更新于2025-09-04 15:30:14
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Atomic layer deposited TiO <sub/>2</sub> -IrO <sub/>x</sub> alloys enable corrosion resistant water oxidation on silicon at high photovoltage.
摘要： We synthesized by atomic layer deposition (ALD) TiO2-IrOx alloys that enable high photovoltages and catalyze water oxidation on silicon metal-insulator-semiconductor (MIS) photoanodes. The ratio of TiO2 to IrOx was precisely controlled by varying the number of ALD cycles for each precursor. Silicon with a 2 nm surface SiO2 layer was coated with TiO2-IrOx alloys ranging in composition from 18-35% iridium relative to the sum of titanium and iridium concentrations. IrOx catalyzed oxygen evolution and imparted a high work function to the TiO2-IrOx alloys, enabling photovoltages during water oxidation that exceeded 600 mV. TiO2 imparted stability and inhibited corrosion of the underlying silicon light absorber. After annealing in forming gas (5% H2 / 95% N2), TiO2-IrOx alloys were stable for 12 hours of continuous water oxidation in 1 M H2SO4. Key properties of the MIS junction affecting electrochemical operation were also extracted by electrochemical impedance spectroscopy. This work demonstrates that alloying by ALD is a promising approach for designing corrosion resistant Schottky contacts with optimized electronic and materials properties for catalyzed, solar driven water oxidation.
关键词： photovoltage,water oxidation,TiO2-IrOx alloys,Atomic layer deposition,corrosion resistance,silicon photoanodes
更新于2025-09-04 15:30:14
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Charge and Coordination Directed Liposome Fusion onto SiO2 and TiO2 Nanoparticles
摘要： TiO2 and SiO2 are very useful materials for building biointerfaces. A particular interesting aspect is their interactions with lipid bilayers. Many past research efforts focused on phosphocholine (PC) lipids, which form supported lipid bilayers (SLB) on SiO2 at physiological conditions but are adsorbed as intact liposomes on TiO2. Low pH was required to form PC SLBs on TiO2. This work intends to understand the surface forces and chemistry responsible for such differences. Two charge neutral lipids: 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 2-((2,3-bis(oleoyloxy)propyl)dimethylammonio)ethyl ethyl phosphate (DOCPe); and two negatively charged lipids: 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) and 2-((2,3-bis(oleoyloxy)propyl)dimethylammonio)ethyl hydrogen phosphate (DOCP) were used. Using calcein leakage assays, adsorption measurement, cryo-TEM, and washing, we concluded that charge is the dominating factor on SiO2. The two neutral lipids form SLB on SiO2 at pH 3 and 7, but the two negatively charged ones cannot form. On TiO2, both charge and coordination chemistry are important. The two anionic lipids formed SLB from pH 3 to 10. DOCP had stronger affinity than DOPS likely due to the tighter terminal phosphate binding of the former. The two neutral liposomes formed SLB only at pH 3, where phosphate interaction and van der Waals force are deemed important. The pH 3 prepared TiO2 DOPC SLBs are destabilized at neutral pH, indicating reversible nature of the interaction. This work has provided new insights into two important materials interacting with common liposomes, which are important for reproducible biosensing, device fabrication, and drug delivery applications.
关键词： coordination chemistry,liposome fusion,SiO2,TiO2,charge,supported lipid bilayers
更新于2025-09-04 15:30:14
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Enhanced Photoinduced Electrocatalytic Oxidation of Methanol Using Pt Nanoparticle-Decorated TiO <sub/>2</sub> –Polyaniline Ternary Nanofibers
摘要： Herein, perylene-3,4,9,10-tetracarboxylic acid-doped polyaniline (PTP) nanofibers with/without photoreactive anatase TiO2 (TiO2?PTP and PTP, respectively) have been successively synthesized and subsequently decorated by Pt nanoparticles (Pt NPs) to prepare Pt?PTP and Pt?TiO2?PTP composites. High-resolution transmission electron microscopy confirms the presence of ～3 nm spherical-shaped Pt NPs on both the composites along with TiO2 on Pt?TiO2?PTP. Pt loading on the composites is deliberately kept similar to compare the methanol electro-oxidation in the two composites. The Pt nanocomposites along with the precursor polyanilines are characterized by optical characterization, X-ray diffraction study, X-ray fluorescence spectroscopy, and Raman spectroscopy. The ternary composite-modified (Pt?TiO2?PTP) electrode demonstrates high electrocatalytic performance for methanol oxidation reaction in acid medium than Pt?PTP and Pt?TiO2. The higher electrochemical surface area (1.7 times), high forward/backward current ratio, and the higher CO tolerance ability for Pt?TiO2?PTP make it a superior catalyst for methanol oxidation reaction in the electrochemical process than Pt?PTP. Moreover, the catalytic activity of Pt?TiO2?PTP is further enhanced significantly with light irradiation. The cooperative effects of photo- and electrocatalysis on methanol oxidation reaction in Pt?TiO2?PTP enhance the methanol oxidation catalytic activity approximately 1.3 times higher in light illumination than in dark. Therefore, the present work will be proficient to get a light-assisted sustainable approach for developing the methanol oxidation reaction activity of Pt NP-containing catalysts in direct methanol fuel cells.
关键词： photo-assisted,TiO2 nanofibers,methanol oxidation,electrocatalysis,Pt nanoparticles
更新于2025-09-04 15:30:14
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Synthesis, Characterization and Photocatalysis of Mesoporous TiO2
摘要： The mesoporous TiO2 nanoparticulate has been prepared by evaporation induced self-assembly method using EO-PO type polyether P123 as a template. The small angle X-ray diffraction, wide angle X-ray diffraction, high-resolution transmission electron microscopy and N2 isothermal adsorption-desorption are used to study the microstructure and morphology of the as-synthesized mesoporous TiO2. The results demonstrate that the mesoporous TiO2 belongs to anatase and the size is 20-30 nm. The sample is prepared using P123 as a template with average pore size distribution of 11.54 nm, specific surface area of 84.83 m2/g and pore volume of 0.234 cm3/g. The as-synthesized mesoporous TiO2 exhibits remarkably high photocatalytic activity of 93.6 % in decomposing formaldehyde under ultraviolet light irradiations for 90 min. This work provides a basic experimental process for the preparation of mesoporous TiO2, which will possess a broad prospect in terms of the applications in improving indoor air quality.
关键词： Photocatalysis,Evaporation induced self-assembly,Mesoporous TiO2,Formaldehyde
更新于2025-09-04 15:30:14
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High Visible Response of Vertical TiO2 Nanoclusters-CdSe Linked by Cysteine
摘要： Vertically oriented single-crystal TiO2 nanoclusters in tetramethylammonium hydroxide solution were synthesized hydrothermally directly on Ti substrate. N-Type semiconducting CdSe nanoparticles were then introduced deep coating TiO2 nanocrystalss via a two-step procedure using cystein as a surface coupling agent, followed by a subsequent electrodeposition process from selenosulfite to form orderly interconnecting heterojunctions. A key result achievement is that although the TiO2 nanocrystalss are less than 1 μm long, under the help of the bifunctional 2-amino-3-sulfhydrylpropanoic acid molecule linking the acceptor and donor materials, the virtue of strong visible absorption of single crystal TiO2 nanoclusters were fully developed in addition of ultraviolet, so that the heterojunction electrode exhibits excellent photoresponse in photoelectrochemical cells to visible lights, whose contribution is rather significant compared with that of ultraviolet lights. Vertical nanoclusters have advantages of leading electrons directly into the metal Ti substrate while maintaining the large surface area towards the electrolyte. These highly ordered nanohybrids are expected to have potential applications in photochemical solar cells with high efficiency.
关键词： TiO2 nanocluster,Visible lights,Sensitization,CdSe,Vertically oriented
更新于2025-09-04 15:30:14
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Optimization of CdS/TiO2 Nanotube-Array Composite Photocatalysts Prepared by Electrodeposition
摘要： Titania nanotube arrays were prepared by titanium anodizing, then CdS/TiO2 nanotube arrays composite photocatalysts were prepared by an AC electrodeposition method for different times. The morphology and crystal structure of the CdS/TiO2 composite photocatalysts were characterized by SEM and XRD. The photoelectrochemical properties of the composites were investigated by means of UV-visible absorption spectra and photocurrent measurements. The photocatalytic activity was evaluated by the degradation of methyl orange under UV-visible light irradiation. The results show that there is an optimum deposited time for the highest photocatalytical activity of the CdS/TiO2 composite photocatalysts under UV-visible light irradiation and the optimum deposited time is determined to 3 min.
关键词： Electrodeposition,Nanotube array,Composite photocatalyst,Methyl orange,CdS/TiO2
更新于2025-09-04 15:30:14
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Influence of Post-deposition Heat Treatments on the Optical Properties of Chemically Deposited Nanocrystalline TiO2 Thin Films
摘要： The aim of this study is to investigate the potentials of TiO2 thin films for device applications. Nanocrystalline single phase of rutile TiO2 thin films have been prepared by Chemical Bath Deposition (CBD) technique at bath temperature range from 75-80°C, keeping other deposition variables constant. The films were then subjected to post-deposition heat treatments with annealing temperatures in the range 373 to 673 K. The optical characterisation was done using the Elmer Lambda-2 spectrometer to investigate the transmittance and absorbance versus wavelength measurements. The data obtained from the transmittance and absorbance measurements were used to deduce the important optical constants. The results show that the energy bandgap was direct, with values in the range ≤1.8 eV for the as-deposited layers and ≥2.2 eV for the annealed layers. At lower temperatures, the band gaps of the annealed samples did not differ significantly from the energy gap (1.8 eV) of the as-deposited film. At higher thermal treatment, the energy gaps increased with the increase in annealing temperatures and a maximum of 2.2 eV for the energy gap was determined for TiO2 film annealed at 673 K. The values of the energy bandgap obtained in study, are within the range suitable for application in photovoltaic solar cell devices and in related photonic applications.
关键词： thermal annealing,Energy band gap,solar cells,TiO2
更新于2025-09-04 15:30:14