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Heterostructures of mesoporous TiO2 and SnO2 nanocatalyst for improved electrochemical oxidation ability of Vitamin B6 in pharmaceutical tablets
摘要： The detection of water soluble vitamins using electrochemical method is widely established in pharmaceutical quality control laboratories, and especially the recent advances in hybrid heterostructure nanomaterials has devoted to enhance the significant analytical parameters like sensitivity, selectivity and fast response time. Herein, we report the synthesis of a hybrid heterostructure comprising SnO2 nanoparticles supported mesoporous TiO2, and the obtained nanocomposite were fabricated over glassy carbon electrode (GCE) for the electrochemical oxidation of vitamin B6 in pharmaceutical tablets. The designed SnO2-TiO2/GC modified electrode exhibits well-defined oxidation peak with lowering over-potential and larger signal response compared to the pristine counterparts, and it is mainly due to the formation of abundant active surface layer offered by SnO2 cocatalyst, and thus significantly enhances the electrochemical surface area. Differential pulse voltammetry (DPV) measurements revealed a sharp increase in the anodic peak current upon addition of increasing concentration of vitamin B6. The analytical performance of the modified electrode displayed a wide linear range (0.1 - 31.4 μM), high selectivity, and excellent sensitivity (759.73 μA mM-1 cm-2) with low detection limit (35 nM). Thus, the resultant mesoporous hybrid nanocatalyst provides an efficient electrochemical platform for determination of various potential analytes.
关键词： electrochemical sensor,Tin oxide (SnO2) cocatalyst,mesoporous,Titanium dioxide (TiO2),Vitamin B6
更新于2025-09-19 17:15:36
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Proof of Concept for Light Conducting Membrane Substrate for UV-Activated Photocatalysis as an Alternative to Chemical Cleaning
摘要： Adopting an effective strategy to control fouling is a necessary requirement for all membrane processes used in the water/wastewater treatment industry to operate sustainably. The use of ultraviolet (UV) activated photocatalysis has been shown to be effective in mitigating ceramic membrane fouling by natural organic matter. The widely used configuration in which light is directed through the polluted water to the membrane’s active layer suffers from inefficiencies brought about by light absorption by the pollutants and light shielding by the cake layer. To address these limitations, directing light through the substrate, instead of through polluted water, was studied. A UV conducting membrane was prepared by dip coating TiO2 onto a sintered glass substrate. The substrate could successfully conduct UV from a lamp source, unlike a typical alumina substrate. The prepared membrane was applied in the filtration of a humic acid solution as a model compound to study natural organic matter membrane fouling. Directing UV through the substrate showed only a 1 percentage point decline in the effectiveness of the cleaning method over two cleaning events from 72% to 71%, while directing UV over the photocatalytic layer had a 9 percentage point decline from 84% to 75%. Adapting the UV-through-substrate configuration could be more useful in maintaining membrane functionality during humic acid filtration than the current method being used.
关键词： photocatalytic membrane,membrane fouling,Titanium dioxide,water treatment
更新于2025-09-19 17:15:36
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A potentially more eco-friendly chemical pathway for production of high purity TiO2 from titanium slag
摘要： TiO2 is an important inorganic material which is commercially produced by either the chloride or the sulfate process. In general, the latter has lower cost and lower entry barrier than the former. However, the environmental impact associated with the sulfate process is more visible than the chloride process because the sulfuric acid with a low concentration (~20 wt%) cannot be cost-effectively recycled; therefore, it has to be neutralized, generating a large amount of wet and useless red gypsum (RG). In this research, a potentially more eco-friendly chemical pathway for TiO2 production from concentrated titanium ore, aka titania slag, is presented. The new method consists of three critical steps including transformation of the titania slag to a lower valence titanium sub-oxide by aluminothermic reduction, digestion by using mild acid, and controlled hydrolysis accompanied by acid recycling. As a result of the phase transformation, the digestion of titanium from the titanium feedstock becomes easier such that it is feasible to use relatively mild acid to replace concentrated acid, reducing the environmental impact from the red gypsum because the need for neutralizing the waste acid can be eliminated. High purity hydrous TiO2 can be prepared after hydrolysis, and the spent liquor can be effectively recycled back to the digestion unit.
关键词： Aluminothermic reduction,Titania slag,Controlled hydrolysis,Titanium dioxide,Mild acid digestion
更新于2025-09-19 17:15:36
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Green Synthesis of Nano Silver on TiO2 Catalyst for Application in Oxidation of Thiophene
摘要： The present research work describes the preparation of silver nanoparticles from silver nitrate, and Tulsi (Ocimum tenuiflorum) leaf extract, impregnation on titanium dioxide (TiO2) and evaluation of the catalytic activity of this nano silver impregnated TiO2 in the oxidation reaction of thiophene. Tertiary-butyl hydroperoxide was used as an oxidant in the reaction. The catalyst was characterized by BET, SEM, XRF, TEM, UV-Vis spectroscopy, XPS and TPR. The effect of process parameters such as speed of agitation, catalyst weight, oxidant to sulfur mole ratio, silver loading in the catalyst and temperature on the oxidation reaction was studied. Both pseudo-homogeneous and heterogeneous kinetic models were considered and applied for the result. The pseudo-homogeneous form of rate equation shows the reaction follows second order kinetics and is endothermic. Langmuir-Hinshelwood kinetic model is proposed, considering the reaction as a heterogeneous one with solid catalyst and found that surface reaction is the rate controlling step. This model is well fitted with experimental data.
关键词： Kinetic model,Tulsi leaf extract,Thiophene,Catalytic oxidation,Titanium dioxide,Silver nanoparticles
更新于2025-09-19 17:15:36
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Scaling-up a heterogeneous H2O2/TiO2/solar-radiation system using the Damk?hler number
摘要： A falling film photocatalytic solar reactor (FFR) and a tubular reactor with compound parabolic collectors (CPCR) were modeled. An empirical reaction mechanism was proposed for the heterogeneous photocatalytic degradation of organic contaminants using TiO2, and H2O2. An analytical kinetic rate was deducted from the mechanism in order to describe the change of H2O2 concentration and the rate of destruction of total organic carbon (TOC). The profiles of the absorption rate of photons in the heterogeneous medium were estimated by using the absorption-scattering radiation six-flux model (SFM). A dimensionless number that we named Damk?hler of a photocatalytic reactor was proposed. Finally, the modeling was validated against experimental data for the TOC destruction obtained from the mineralization of dicloxacillin (DCX) and 4-chlorophenol (4-CP), which we considered as model pollutants.
关键词： Photoreaction scaling-up,Photoreactor design,Emerging pollutants,Titanium dioxide
更新于2025-09-19 17:15:36
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Performance of TiO2 Based Dye-Sensitized Solar Cells Fabricated Using Coomassie Brilliant Blue in Acetonitrile Solution
摘要： The synthetic dye sensitizer based solar cells were successfully fabricated and photovoltaic performance was measured. Titanium dioxide (TiO2) nanoparticles were synthesized using sol–gel technique. The XRD and HRTEM analysis were carried out to determine the structural and morphological property of TiO2 nanoparticles. The crystalline sizes of the TiO2 particles were determined by XRD and were confirmed by TEM. The synthetic Coomassie Brilliant Blue (CBB) dissolved in acetonitrile was used as a dye in the nanocrystalline Tio2 solar cell. TiO2 films on FTO glass substrate were prepared by simple doctor blade technique. The dye was characterized by UV-Vis absorption spectroscopic analysis. The strong absorption of the CBB dye enhanced the DSSC property. The results showed that TiO2 as photoanode and CBB as a sensitizers showed good conversion efficiency.
关键词： CBB,DSSC,TEM,XRD,Titanium dioxide
更新于2025-09-19 17:13:59
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Facile graft copolymer template synthesis of mesoporous polymeric metal-organic frameworks to produce mesoporous TiO2: Promising platforms for photovoltaic and photocatalytic applications
摘要： Mesoporous polymeric metal-organic frameworks (mesoporous polymeric MOFs) are prepared on fluorine-doped tin oxide (FTO) substrate using hydrophilic terephthalic acid as the ligands, titanium isopropoxide as polymeric MOF precursors, and amphiphilic graft copolymers (i.e., poly(vinyl chloride)-graft-poly(oxyethylene methacrylate) (PVC-g-POEM) as structure-directing agents. The hydrophilic POEM chains in amphiphilic graft copolymers interact with the hydrophilic ligands and polymeric MOF precursors. Following thermal treatment at 500 °C, mesoporous polymeric MOFs are transformed to mesoporous TiO2 with high specific surface area and crystallinity, suitable for photovoltaic and photocatalytic applications. Solid-state dye-sensitized solar cells (ssDSSCs) and dye-sensitized solar cells (DSSCs) fabricated with mesoporous TiO2 photoanodes have efficiencies of 7.45 and 8.43 % at 100 mW/cm2, which is much higher than that of ssDSSCs and DSSCs with photoanodes of conventional TiO2 (5.36 and 7.14 %), respectively. The enhanced efficiency is attributed to good interconnectivity, larger surface area, and high porosity of the mesoporous TiO2, which results in suppressed interfacial charge recombination loss, enhanced electron transport, increased dye loading, and facilitated penetration of the electrolytes. Mesoporous TiO2 shows excellent activity as a photocatalyst for the degradation of humic acid under UV light irradiation.
关键词： Photocatalyst,Dye-sensitized solar cell (DSSC),Metal-organic framework (MOF),Graft copolymer,Titanium dioxide (TiO2),Polymerized ionic liquid,Mesoporous
更新于2025-09-19 17:13:59
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Hydrothermally-Grown TiO2 Thin Film-Based Metal–Semiconductor–Metal UV Photodetector
摘要： A metal–semiconductor–metal (MSM) ultraviolet photodetector has been fabricated by using hydrothermally-grown TiO2 thin films. Ag paint was used as a contact electrode which showed the good ohmic contact between the metal–semiconductor junctions. The effect of deposition time on the structural, morphological and photodetector properties have been studied. The prepared TiO2 thin films are polycrystalline and show a rutile crystal structure with the preferred orientation along the (110) plane. The MSM UV photodetector was illuminated under a UV lamp with an intensity of 1.8 lW/cm2 and at 5-V bias. The photocurrent of the device increased linearly with the applied voltage. The maximum photocurrent of 3.96 lA was obtained for the film deposited at 5 h and maximum spectral photoresponsivity was 13.29 A/W. The device showed a fast optical switching behavior. The high responsivity and fast photoresponse shows that fabricated TiO2 detectors are good candidates for ultraviolet photodetectors.
关键词： MSM UV photodetector,Titanium dioxide,photoresponsivity,hydrothermal method
更新于2025-09-19 17:13:59
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Photocatalytic degradation of gaseous toluene using self-assembled air filter based on chitosan/activated carbon/TiO2
摘要： Photocatalytic filters are integrated with air purifiers and ventilation systems to remove volatile organic compounds (VOCs) from indoor air. However, the filters, generally prepared by dip or spray coating, are less stable as the deposited TiO2 NPs are prone to be blown off by treated air. In the present study, we propose a novel filter preparation method based on self-assembly of activated carbon (AC) and TiO2 on non-woven polyethylene terephthalate (PET) fabric using chitosan (CS). The prepared filter (CSAT-PET) was characterized for morphological and chemical properties which revealed the homogeneity and chemical bonding of deposited TiO2. Photocatalytic activity of the prepared filter was evaluated for toluene degradation (200–600 ppb) under dark and UV illumination. Toluene removal efficiency reached 91% over CSAT-PET, while it was only 62% over pure TiO2 filter. About 40% of toluene removal was achieved by adsorption on CSAT-PET. Furthermore, CSAT-PET showed robust performance for selected face velocity ranging from 0.5 to 1.5 m/s and, the reaction rate followed Langmuir-Hinshelwood model. FTIR study identified benzaldehyde and benzoic acid as adsorbed intermediates. A UV-induced filter regeneration partially released the adsorbed species. CSAT-PET showed consistent toluene removal and intact morphology over five degradation cycles. The Box-Behnken design (BBD) in RSM was applied to optimize the filter preparation method. The optimum values of TiO2, AC and CS loading were 38.3 g/m2, 52.6 g/m2 and 2.06% (w/v), respectively which exhibited highest removal efficiency for toluene (93%). The proposed methodology can be adapted to fabricate low-cost, stable, and reusable photocatalytic filter for air purification applications.
关键词： Volatile organic compounds,Air filter,Photocatalytic oxidation,Titanium dioxide,Activated carbon,Self-assembly
更新于2025-09-19 17:13:59
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SILICA a?? CARBON QUANTUM DOTS DECORATED TITANIUM DIOXIDE AS SUNLIGHT-DRIVEN PHOTOCATALYST TO DIMINISH ACETAMINOPHEN FROM AQUATIC ENVIRONMENT
摘要： The presence of pharmaceutical compound (i.e., acetaminophen) in aquatic environment has been declared as environmental issue since researchers found that it has potential risk to human health. Photocatalytic process as a promising method for waste degradation commonly employs titanium dioxide, TiO2. However, TiO2 has narrow light absorption and rapid charge recombination resulting in ineffective photocatalytic activity. In this study, silica – carbon quantum dots (Si-CQDs) from rice husk are decorated into TiO2 matrix through facile mixing approach to minimize the limitations of TiO2. Preliminary studies regarding TiO2 transformation and Si-CQDs incorporation in various amount were systematically investigated. It is observed that 1 wt% is the optimum amount of Si-CQDs in composite in order to maximize the photocatalytic ability of TiO2. Under sunlight irradiation, 1 wt% Si-CQDs/TiO2 composite is able to completely degrade 5 mg/L of acetaminophen within 240 min (33.3% faster than pure TiO2). The excellent performance of the composite is attributed to synergistic effect of Si-CQDs addition on TiO2 surface, which acted as photo sensitizer and electron trapper. Si-CQDs extend light absorption of TiO2 by reducing band gap energy from 3.20 to 3.12 eV, as confirmed by UV-Vis Diffuse Reflectance Spectroscopy (DRS) spectra. Photoluminescence (PL) spectra and N2 sorption isotherm reveal that Si-CQDs addition prolongs the lifetime of charge separation and improves surface area (17% larger than TiO2), respectively. The composite of Si-CQDs/TiO2 also demonstrates good stability which is beneficial for pharmaceutical waste removal in the future.
关键词： sunlight,photocatalyst,Titanium dioxide,acetaminophen,carbon quantum dots,pharmaceutical
更新于2025-09-19 17:13:59