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Photocatalytic hydrogen evolution assisted by aqueous (waste)biomass under simulated solar light: Oxidized g-C3N4 vs. P25 titanium dioxide
摘要： Oxidized graphitic carbon nitride (o-g-C3N4) and Evonik AEROXIDE? P25 TiO2 were compared for lab-scale photocatalytic H2 evolution from aqueous sacrificial biomass-derivatives, under simulated solar light. Experiments in aqueous starch using Pt or Cu–Ni as the co-catalysts indicated that H2 production is affected by co-catalyst type and loading, with the greatest hydrogen evolution rates (HER) up to 453 and 806 μmol g?1 h?1 using TiO2 coupled with 3 wt% Cu–Ni or 0.5 wt% Pt, respectively. Despite the lower surface area, o-g-C3N4 gave HERs up to 168 and 593 μmol g?1 h?1 coupled with 3 wt% Cu–Ni or 3 wt% Pt. From mono- and di-saccharide solutions, H2 evolution was in the range 504–1170 μmol g?1 h?1 for Pt/TiO2 and 339–912 μmol g?1 h?1 for Cu–Ni/TiO2, respectively; o-g-C3N4 was efficient as well, providing HERs of 90–610 μmol g?1 h?1. The semiconductors were tested in sugar-rich wastewaters obtaining HERs up to 286 μmol g?1 h?1. Although HERs were lower compared to Pt/TiO2, a cheap, eco-friendly and non-nanometric catalyst such as o-g-C3N4, coupled to non-noble metals, provided a more sustainable H2 evolution.
关键词： Biomass,Graphitic carbon nitride,Hydrogen,Photocatalysis,Solar light,Titanium dioxide
更新于2025-09-23 15:22:29
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Enhanced photocatalytic activity of hierarchical titanium dioxide microspheres with combining carbon nanotubes as “e-bridge”
摘要： Enhancing photocatalytic activity of titanium dioxide (TiO2) by efficient charge separation is essential but challenging. Herein, the recombination between photo-generated e–-h+ pairs is effectively hindered owing to the “e-bridge” formed between hierarchical TiO2 microspheres and carbon nanotubes (CNTs). The as-prepared three-dimensional TiO2 microspheres covered by intercrossing lamellar crystals are abundant in pores and sharp edges, forming an ideal interface with large surface area and numerous active sites for photocatalysis. Combined with CNTs, the TiO2 microspheres are connected and stabilized. Moreover, the CNTs serve as pathways for electrons, benefiting the effective separation of e–-h+ pairs and accounting for the superior photocatalytic activity. Transient fluorescence spectra shows that the lifetime of electrons on TiO2 prolongs from 5.23 ns to 10.14 ns assisted by CNTs. In aqueous matrix, electrons gathering on the CNTs can react with O2 to produce O2–, and simultaneously, plenty of holes left in TiO2 host generate OH by oxidizing adsorbed H2O, producing abundant active species for photocatalytic degradation of 4-nitrophenol. The highest degradation efficiency in removing organic contaminants is achieved on TiO2@CNTs hybridized with CNTs weight ratio being 5%.
关键词： e-Bridge,Titanium dioxide,Carbon nanotubes,Organic pollutant,Photocatalytic degradation
更新于2025-09-23 15:22:29
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Performance of various commercial TiO <sub/>2</sub> in photocatalytic degradation of a mixture of indoor air pollutants: Effect of photocatalyst and operating parameters
摘要： Photocatalytic oxidation (PCO) air cleaners can be installed in air handling units to reduce occupants’ exposure to hazardous gases, boost indoor air quality, and concomitantly lower HVAC energy consumption by lowering the required ventilation rate. In this work, photocatalytic activity of four commercialized titanium dioxide photocatalysts (P25, PC500, UV100, and S5-300A) for treating a mixture of seven prevalent volatile organic compounds (VOCs) were assessed in a continuous flow reactor. The impacts of major experimental factors namely concentration (15-100 ppb), relative humidity level (0-60% at 23?C), and residence time (0.012-0.05 s) on the removal efficiency and by-products generation were examined. Photocatalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). UV100 possessed the highest values for total VOC removal efficiency, which could be attributed to its large surface area, high porosity, good crystallinity, and large population of surface hydroxyls. Regarding relative humidity, two dominant trends were found: i) increasing the humidity resulted in lower removal efficiencies, or ii) existence of an optimum humidity level in some cases. The treatment efficiency followed the order: alcohols > ketones > aromatics > alkanes. The main by-products in the gas phase were formaldehyde, acetaldehyde, acetone, and propionaldehyde.
关键词： titanium dioxide,volatile organic compounds,indoor air quality,photocatalytic oxidation,relative humidity,residence time,by-products
更新于2025-09-23 15:22:29
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Synthesis, characterization of TiO <sub/>2</sub> nano particles for enhancement of electron transport application in DSSC with Cu-BPCA Dye
摘要： Dye-sensitized solar cells [DSSCs] have attracted extensive attention due to their potential low cost and high energy efficiency, rendering them one of the most promising system for solar-to-energy conversion. The DSSC efficiency was enhanced by intermixing with the use of TiO2 nanoparticles which provides high surface area for accommodating the light-absorbing sensitizer and also the stable conductor for photo generated electrons. In hydrothermal method, the TiO2 nanoparticles synthesis depends on temperature. TiO2 nano particles diameter depends on different autoclaving temperature.TiO2 nanoparticles have been coated on ITO glasses by screen printing method. In this work, we have synthesized TiO2 nano particles which can provide a fast way for electron transport and reduced trapping of photo injected electrons during the path of back contact. The DSSCs were fabricated using the ruthenium dye and electrolyte (I3/I3-). The crystalline structure of TiO2 has been characterized by DLS, X-ray diffraction, SEM and TEM. The absorption spectra measured by using UV-Vis spectrometer. The IR spectrum has been recorded to know the peaks of Ti-O-Ti in powder sample. It has been found that the efficiency of DSSC was highly affected by the properties of nano particles.
关键词： Nanoparticles,Dye,DSSC,Titanium Dioxide (TiO2)
更新于2025-09-23 15:22:29
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Enhanced Photocatalytic Degradation of Methylene Blue by Using Au-TiO<sub>2</sub>
摘要： In this work, Au-TiO2 nanoparticles (NPs) were synthesized in a single step by flame spray pyrolysis (FSP) method. X-ray diffraction (XRD) results indicated that phase structures of all samples TiO2 were the mixture of anatase and rutile phases. High resolution transmission electron microscopy (HRTEM) showed that dark spots of Au NPs deposited on larger TiO2 nanoparticles. HRTEM results indicated TiO2 NPs were average crystallite size in the range of 10–30 nm whereas the average diameter of Au NPs was about 5–10 nm. UV–Vis absorption spectroscopy technique showed peaks attributable of surface plasmon resonance (SPR) to Au NPs loaded on TiO2 in the wavelength of 500–630 nm. The Au-TiO2 NPs showed excellent photocatalytic activity for the degradation of methylene blue (MB) under UV-Vis irradiation. It was found that 0.25 mol% Au-TiO2 which was a better photocatalyst than others under the same reaction conditions. The results showed that Au NPs-loading could effectively improve the photocatalytic activities of TiO2.
关键词： Titanium Dioxide,Photocatalytic,Degradation,Gold,Methylene Blue
更新于2025-09-23 15:22:29
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Enhanced Photocatalytic Activity of Titania by Co-Doping with Mo and W
摘要： Various W and Mo co-doped titanium dioxide (TiO2) materials were obtained through the EISA (Evaporation-Induced Self-Assembly) method and then tested as photocatalysts in the degradation of 4-chlorophenol. The synthesized materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy (RS), N2 physisorption, UV-vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The results showed that the W-Mo-TiO2 catalysts have a high surface area of about 191 m2/g, and the presence of an anatase crystalline phase. The co-doped materials exhibited smaller crystallite sizes than those with one dopant, since the crystallinity is inhibited by the presence of both species. In addition, tungsten and molybdenum dopants are distributed and are incorporated into the anatase structure of TiO2, due to changes in red parameters and lattice expansion. Under our experimental conditions, the co-doped TiO2 catalyst presented 46% more 4-chlorophenol degradation than Degussa P25. The incorporation of two dopant cations in titania improved its photocatalytic performance, which was attributed to a cooperative effect by decreasing the recombination of photogenerated charges, high radiation absorption capacity, high surface areas, and low crystallinity. When TiO2 is co-doped with the same amount of both cations (1 wt.%), the highest degradation and mineralization (97% and 74%, respectively) is achieved. Quinones were the main intermediates in the 4-chlorophenol oxidation by W-Mo-TiO2 and 1,2,4-benzenetriol was incompletely degraded.
关键词： W-Mo dopants,photocatalytic activity,nanoparticles,titanium dioxide
更新于2025-09-23 15:22:29
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Influence of Titanium Dioxide Preparation Method on Photocatalytic Degradation of Organic Dyes
摘要： Titanium catalysts (TiO2) were synthesized by three different methods. Their photocatalytic activity was validated through photodegradation of Reactive Red 45 (RR45) azo dye and Acid Blue 25 (AB25) anthraquinone dye in an aqueous solution under UV irradiation. TiO2 photocatalysts were characterized by FTIR, XRD and SEM. Photosensitivity and TiO2 activity range were characterized by UV/Vis spectroscopy. Photocatalytic validation has been made by way of determining the degree of RR45 and AB25 removal. TOC was determined as a measure of the mineralization of RR45 and AB25 by photocatalysis. The stability of TiO2 catalysts and a possibility of using them in consecutive photocatalysis cycles have also been studied. The results show that the photocatalytic efficiency depends on the crystal structure of TiO2. The size of crystallites depends on synthesis conditions. From the results of photocatalytic efficiency it is concluded that the chemical interaction between a catalyst and a dye strongly depends on the dye chemical structure.
关键词： organic dyes,wastewater treatment,photocatalysis,titanium dioxide
更新于2025-09-23 15:22:29
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Conductive TiO2 nanorods via surface coating by antimony doped tin dioxide
摘要： Titanium dioxide (TiO2) has been widely used as the white pigment in paintings and coatings. It is of significance to endow TiO2 powders with the high conductivity to extend its application. In this research, rutile TiO2 nanorods were prepared as the substrate material. Further the surface coating by antimony doped tin dioxide (SbeSnO2) shell layers was achieved to obtain conductive TiO2 nanorods. The morphology and structure of TiO2@SbeSnO2 nanorods was mainly focused on to obtain high conductivity by optimizing the calcination temperature. When the temperature was properly applied at nearly 500 °C, the calcination led to the fusion and attachment of SbeSnO2 crystalline regions on the surface of TiO2 nanorods, forming a continuous intact coating layer and thus getting lower volume electrical resistivity of the composite nanopowder. However, after calcination at 600 °C or higher temperature, the integrity of SbeSnO2 shell layers would be destroyed, resulting in the increased electrical resistivity. The conductive TiO2 nanorods obtained at the optimized reaction condition showed a very low resistivity of 52 ± 1.6 Ω cm, in contrast to 105 Ω cm of the pure TiO2. The conductive TiO2 nanorods would be excellent candidate for antistatic or electromagnetic shielding applications in coatings.
关键词： Core-shell,Calcination,Titanium dioxide,Conductive
更新于2025-09-23 15:22:29
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AIP Conference Proceedings [Author(s) PROCEEDINGS OF THE 3RD INTERNATIONAL SYMPOSIUM ON CURRENT PROGRESS IN MATHEMATICS AND SCIENCES 2017 (ISCPMS2017) - Bali, Indonesia (26–27 July 2017)] - Bismuth vanadate (BiVO4) as counter electrode in the newly developed catalysis zone of modified cadmium sulfide (CdS) sensitized solar cell for hydrogen production
摘要： Recently we developed a modified quantum dot dyes sensitized solar cell (QD-DSSC) having catalysis zone extension for hydrogen production. The DSSC section comprised of CdS sensitized highly order Titanium dioxidenanotube (CdS-HOTN) immobilized on Ti plate, Na2S/S containing electrolyte, and Pt covered SnO-F (fluorine doped tin oxide) glass plate (hence Pt/SnO-F/Glass). While the catalysis zone comprised of an extension of Ti support, as cathode, and the respected counter electrode was an extension of SnO-F glass, which was covered by BiVO4 film, both from respected DSSC section. In this presentation, we will focus on the role of the BiVO4 in our newly developed system. The bismuth vanadate was prepared by co-precipitation method with ammonia and calcination to obtain a fine powder. The BiVO4 fine powder were then deposited onto SnO-F glass plate and characterized by FT-IR, UV–vis diffused reflectance spectroscopy, SEM and X-ray diffraction. The characterization results revealed that the BiVO4 film, typically, has a band gap of 2.35 eV, characteristic of IR peaks represent the –V-O-, and –Bi-O-V- bonds, having a crystal phase as BiVO4 monoclinic scheelite with a typically crystallite size of 74.06 nm. The photo-electro-chemical properties of the BiVO4 film photo-anode was investigated by a linear sweep voltammetry and multi pulse amperometry, which revealed that the current response under the visible light was 0.03 mA/cm2. Further investigation when the BiVO4 film was incorporated into the modified QD-DSSC, the system (catalysis zone section), under solely visible light, was able to split the water into hydrogen and molecular oxygen. A brief discussion of the newly developed modified QD-DSSC, especially on the role of BiVO4 counter electrode in the catalysis zone will be presented, to gain a better insight in our new type artificial photosynthesis.
关键词： water splitting,titanium dioxide nanotubes,cadmium sulfide,artificial photosynthesis,modified dyes sensitized solar cell,Bismuth vanadate
更新于2025-09-23 15:21:21
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Steady-state Electrochemiluminescence at Single Semiconductive Titanium Dioxide Nanoparticles for Local Sensing of Single Cells
摘要： Obtaining steady-state bright electrochemiluminescence (ECL) at single nanoparticles is crucial but challenging for the realization of the single-nanoparticle electrochemical sensing of single cells. In this work, steady-state bright ECL is implemented at single semiconductive titanium dioxide (TiO2) nanoparticles for sensing the local efflux from single living cells. Oxygen vacancies on the surface of rutile TiO2 nanoparticles have a high affinity for hydrogen peroxides that are not easily passivated upon exposure to voltage. Therefore, the steady-state adsorption of hydrogen peroxide by the TiO2 nanoparticle surface permits the continuous electrochemical generation of superoxide and hydroxyl radicals by electrons and surface-trapped holes at the nanoparticles, resulting in constant ECL under physiological conditions. This steady-state luminescence during continuous imaging is correlated with the concentration of hydrogen peroxide, leading to the local ECL visualization of hydrogen peroxide efflux from single cells. The successful local ECL imaging demonstrated herein provides an unprecedented approach to enable subcellular electroanalysis using single nanoparticles.
关键词： electrochemiluminescence,titanium dioxide,single cells,hydrogen peroxide,single nanoparticles
更新于2025-09-23 15:21:21