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Ternary photocatalyst based on conducting polymer doped functionalized multiwall carbon nanotubes decorated with nanorods of metal oxide
摘要： The ternary photocatalyst PEDOT@ZnO@MWCNTs was fabricated using chemical oxidative method of polymerization. The fabrication of the catalyst was further investigated using spectroscopic techniques namely UV–Visible, FT-IR, XRD and the surface morphology was explored by SEM and TEM. The photodegradation kinetics of the azo dye MO followed pseudo first order kinetics at different pH. The photodegradation of the dye was studied in presence of PEDOT@ZnO@MWCNTs on irradiation with visible source of light. The redox activity of the photocatalyst was investigated by cyclic voltammetric technique and the mechanism of the photocatalysis was established via electronic impedance study. The evaluated value of rate constant, half life time period and the degradation efficiency sustenance the competence of the photocatalyst for the photodegradation of MO at the optimum pH value of 3.5. The chemical oxygen demand (COD) analysis was also favored the mineralization of the dye in presence of photocatalyst.
关键词： Photocatalyst,Methyl orange,Kinetics,Photodegradation,Electronic impedance study
更新于2025-11-21 11:18:25
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Growth Process and CQDs-modified Bi4Ti3O12 Square Plates with Enhanced Photocatalytic Performance
摘要： Bi4Ti3O12 square plates were synthesized via a hydrothermal route, and their growth process was systematically investigated. Carbon quantum dots (CQDs) were prepared using glucose as the carbon source, which were then assembled on the surface of Bi4Ti3O12 square plates via a hydrothermal route with the aim of enhancing the photocatalytic performance. XRD (X-ray powder diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), UV-vis DRS (diffuse re?ectance spectroscopy), XPS (X-ray photoelectron spectroscopy), FTIR (Fourier transform infrared spectroscopy), PL (photoluminescence) spectroscopy, EIS (electrochemical impedance spectroscopy) and photocurrent spectroscopy were used to systematically characterize the as-prepared samples. It is demonstrated that the decoration of CQDs on Bi4Ti3O12 plates leads to an increased visible light absorption, slightly increased bandgap, increased photocurrent density, decreased charge-transfer resistance, and decreased PL intensity. Simulated sunlight and visible light were separately used as a light source to evaluate the photocatalytic activity of the samples toward the degradation of RhB in aqueous solution. Under both simulated sunlight and visible light irradiation, CQDs@Bi4Ti3O12 composites with an appropriate amount of CQDs exhibit obviously enhanced photocatalytic performance. However, the decoration of excessive CQDs gives rise to a decrease in the photocatalytic activity. The enhanced photocatalytic activity of CQDs-modi?ed Bi4Ti3O12 can be attributed to the following reasons: (1) The electron transfer between Bi4Ti3O12 and CQDs promotes an ef?cient separation of photogenerated electron/hole pairs in Bi4Ti3O12; (2) the up-conversion photoluminescence emitted from CQDs could induce the generation of additional electron/hole pairs in Bi4Ti3O12; and (3) the photoexcited electrons in CQDs could participate in the photocatalytic reactions.
关键词： photocatalytic mechanism,photodegradation of RhB,CQDs@Bi4Ti3O12 composites,Bi4Ti3O12 square plates,CQDs
更新于2025-11-19 16:46:39
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Ag1.69Sb2.27O6.25 coupled carbon nitride photocatalyst with high redox potential for efficient multifunctional environmental applications
摘要： Most photocatalysts cannot exhibit high efficiency to remove both gaseous and aqueous pollutants due to the limitation of redox potential and chemical property of photocatalyst itself, which will hinder the broad application of the photocatalysts. Herein, silver antimonite (Ag1.69Sb2.27O6.25) is coupled with polymeric carbon nitride (CN) as efficient photocatalyst for various environmental remediation reactions. The UV-visible light adsorption spectra, valence band X-ray photoelectron spectroscopy, and electron spin resonance spectra of different photogenerated radicals have confirmed that the transfer of electrons and holes have high redox potential to produce reactive O2?- and OH?. The Ag1.69Sb2.27O6.25 coupled CN photocatalyst produces much enhanced activity in removing various pollutants in that it exhibits about 15 folds as CN in mineralizing gaseous isopropanol into CO2, 5 folds as Ag1.69Sb2.27O6.25 in destructing aqueous oxytetracycline hydrochloride, and 10 folds as Ag1.69Sb2.27O6.25 in decoloring methylene blue under the irradiation of visible light. Control experiments in presence of scavengers p-benzoquinone and coumarin have revealed that both electrons and holes in heterojunctions participate in degradation reactions, which induce the much enhanced photocatalytic activity in removing pollutants. This study provides a facile strategy to design photocatalysts for efficient multifunctional environmental applications.
关键词： Heterojunction,Photocatalysis,Photodegradation,Silver antimonites,environmental remediation
更新于2025-11-14 17:04:02
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Mesoporous TiO2-BiOBr Microspheres with Tailorable Adsorption Capacities for Photodegradation of Organic Water Pollutants: Probing Adsorption-Photocatalysis Synergy by Combining Experiments and Kinetic Modeling
摘要： Understanding adsorption-photocatalysis synergy helps advance solar-driven photodegradation of organic wastewater pollutants. To evaluate the synergy, mesoporous TiO2(amorphous)-BiOBr microspheres were facilely synthesized as model photocatalysts and characterized by XRD, SEM, TEM/HRTEM, XPS, nitrogen adsorption-desorption, UV-vis DRS, photoluminescence, and FTIR. The characterizations and photodegradation tests suggested that the composites had both adsorption sites and photocatalysis sites on BiOBr phase, while homogeneously distributed TiO2 in BiOBr microplates tailored the size of BiOBr crystallites. Accordingly, surface areas of the composites spanned from 22 to 155 m2/g and adsorption capacities for methyl orange (MO) ranged from 16 to 54 mg/g, controlled by the TiO2 content. In addition to experiments, kinetic modeling that combined adsorption with photocatalysis was developed and aided elucidating the synergy and quantitatively evaluating the composites with extracted rate constants from experimental data. The rate constant of the composite (Ti/Bi = 0.6) was calculated to be 3 times that of the pure BiOBr. Though adsorption promoted MO photodegradation, the capacity of the composite for MO adsorption and photodegradation decreased dramatically during the cycling tests. Nevertheless, this problem did not happen during photodegradation of rhodamine B and phenol on the composite and photodegradation of MO on pure BiOBr. This was explained by possible accumulation of degradation intermediates on the composite surface. This study provides a useful approach to investigate the adsorption-photocatalysis synergy from the perspectives of experiments and kinetic modeling and implies the necessity of scrutinizing the adverse effects of high levels of adsorption on recyclability of the photocatalysts.
关键词： Organic pollutants photodegradation,Kinetic modeling,TiO2-BiOBr microspheres,Tailorable adsorption capacities,Adsorption-photocatalysis synergy
更新于2025-11-14 17:03:37
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Ups and Downs of Water Photodecolorization by Nanocomposite Polymer Nanofibers
摘要： Given the exponentially expanding water pollution causing water scarcity, there is an urgent need for operative nanotechnological systems that can purify water, with insignificant energy consumption, and rapidly. Here, we introduce a nanocomposite system based on TiO2 nanoparticles (NPs) and PES nanofibers (NFs) that can adsorb and then photodecompose organic water pollutants such as dye molecules. We evaluate pros and cons of this system with respect to its purification efficiency and structural properties that can be impacted by the photocatalytic activity of the nanofillers. While the material is superhydrophilic and able to remove 95% methylene blue (MB) from water via adsorption/photodecomposition, its thermomechanical properties decline upon UV irradiation. However, these properties still remain at the level of the neat NFs. The removal behavior is modeled by the first- and second-order kinetic models from the kinetic point of view. The nanocomposite NFs’ removal behavior complies much better with the second-order kinetic model. Overall, such feedbacks implied that the nanocomposite can be effectively applied for water treatment and the structural properties are still as reliable as those of the neat counterpart.
关键词： nanofiber,photodegradation,dye removal,water treatment,photocatalysis
更新于2025-11-14 17:03:37
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Understanding the performance of a paper‐based UV exposure sensor: The photodegradation mechanism of brilliant blue FCF in the presence of TiO <sub/>2</sub> photocatalysts in both the solid‐state and solution
摘要： Rationale: The decolouration of brilliant blue FCF by the action of TiO2 under UV exposure has been recently reported as the basis of a paper-based sensor for monitoring UV sun exposure. The mechanism of brilliant blue FCF photodegradation in the presence of the photocatalyst and the resulting photoproducts are thus far unknown. Methods: The UV initiated photodegradation of brilliant blue FCF in the presence of TiO2 for both the aqueous and the solid state was investigated. Degradation in the solid state was observed using matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-MS). Decomposition of the dye in the aqueous state was analysed using liquid chromatography mass spectrometry (LC/MS) and ultraviolet-visible (UV-Vis) spectroscopy. Results: After UV radiation exposure, the brilliant blue FCF base peak [M1-H+NH4]+ (m/z calc. 766.194 found 766.194) decreased in the LC/MS chromatogram with a concomitant appearance of BB-FCF decomposition products involving the sequential loss of the N-ethyl- and N-methylbenzene sulfonate (MBSA) groups, assigned as [M2+H]+ (-MBSA, calc. 579.163 found 579.162), [M3+H]+ (-MBSA, -Et, calc. 551.131 found 551.131), [M4+H]+ (-2MBSA, calc. 409.158 found 409.158), [M5+H]+ (-2MBSA, -Et, calc. 381.127 found 381.127). Ions [M2+H]+ and [M3+H]+ were also identified in the photodegradation products using MALDI-MS. Observation by UV-vis indicated a decrease in the solution absorbance maxima and an associated blue-shift upon UV exposure in solution. Conclusion: The LC/MS analysis indicated two main oxidation processes. The most obvious was attack of the N-methylene, eliminating either ethyl or MBSA groups. The presence of the hydroxylated decomposition product M13 ([M13+H]+ calc. 595.157, found 595.157) supported this assignment. In addition, the detection of photoproduct M8, proposed to be 3-((ethylamino)methyl)benzenesulfonic acid ([M8+H]+ calc. 216.069 found 216.069), indicates an aryl-oxidative elimination. The absence of the aryl-hydroxy products normally expected to accompany the formation of M8 is proposed to be due to TiO2 binding catechol-like derivatives, which are then removed upon filtration.
关键词： TiO2,UV sensor,Photodegradation,Brilliant blue FCF
更新于2025-11-14 15:25:21
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AIP Conference Proceedings [Author(s) 2ND INTERNATIONAL CONFERENCE ON CHEMISTRY, CHEMICAL PROCESS AND ENGINEERING (IC3PE) - Yogyakarta, Indonesia (14 August 2018)] - Enhanced photocatalytic activity of WO3 nanoparticles loaded with carbon
摘要： Enhanced photocatalytic activity of WO3 was attempted by carbon nanodots (C-dots) loading. C-dots were prepared using citric acid and urea for enhancing photocatalytic activity of WO3. Physicochemical character of C-dots was studied by fluorescence spectrophotometry and for the modified WO3, evaluation was studied by using x-ray diffraction (XRD) and scanning electron microscope (SEM). Effect of varied citric acid: urea ratio to photocatalytic activity was evaluated in methylene blue photodegradation. Increasing photocatalytic activity was achived by higher intensity in blue color range that obtained by higher urea molar ratio. Kinetics of reaction obey pseudo-first order and pseudo-second order reaction. Reaction reached 80% MB degradation for an hour treatment for 50mM of methylene blue solution.
关键词： photocatalytic activity,methylene blue photodegradation,WO3 nanoparticles,carbon nanodots
更新于2025-11-14 15:15:56
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Photodegradation of methylene blue by mechanosynthesized BiFeO <sub/>3</sub> submicron particles
摘要： In this paper, the photocatalytic activity of bismuth ferrite particles synthesized by high-energy ball milling is evaluated by considering the degradation of methylene blue solutions. Once chemical routes are extensively used to produce these kind of photocatalytic reactors, this mechanochemical route has the advantage of large-scale and low-cost production. The structural, microstructural and optical properties of bismuth ferrite powders are investigated and the photocatalytic efficiency is experimentally proved. The results show a degradation of 95% of the methylene blue dye, which became complete after the addition of the H2O2 oxidizing agent and 15 min of illumination.
关键词： photodegradation,bismuth ferrite,Photocatalysis
更新于2025-10-22 19:40:53
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Application of chemometric methods to resolve intermediates formed during photo- catalytic degradation of methyl orange and textile wastewater from Ethiopia
摘要： The efficiency of two catalysts (TiO2 and TiO2 supported on zeolite) for the photocatalytic degradation of methyl orange dye and wastewaters from Ethiopian textile industry was evaluated by chemometric methods from UV/Vis data of the reaction mixtures at different times. Multivariate curve resolution statistical analysis combined with an alternating least squares algorithm (MCR-ALS) proved to be an efficient method to resolve the different intermediates present during the photocatalytic degradation of the pollutants and to provide information about their evolution with time. Methyl orange photodegradation at pH = 3 showed different intermediate and concentration profiles than at pH = 6. The evolution of intermediates from textile wastewater photodegradation could also be resolved by this method. From the concentration profile or the reactants, a kinetic study was done. Results revealed that all the photodegradation reactions followed a first order kinetics. When TiO2 supported in Zeolite is used, reactions are in general slower, probably due to a mechanism of adsorption/desorption.
关键词： Wastewater,Chemometrics,Dye photodegradation,Methyl Orange,MCR-ALS
更新于2025-09-23 15:23:52
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Straw Degradation Behaviors under Different Conditions of Relative Air Humidity and Ultraviolet-A Irradiation
摘要： In this study, straw was degraded continuously for 150 days under one of three levels of relative air humidity (RH) (90%, 60%, or 30%) to estimate the effect of humidity on straw biodegradation. Moreover, straw was treated with ultraviolet (UV)-A irradiation + 90% RH for 180 days to evaluate the interaction between photodegradation and biodegradation. The effects of 30% and 60% RH on straw degradation was inconspicuous. Straw mass losses at 90% RH and UV-A + 90% RH were 18.5% and 39.1%, respectively. BIOLOG analysis showed that filamentous fungi played a major role in straw biodegradation. Thermogravimetric analysis showed that treatment with UV-A + 90% RH tended to increase the maximum pyrolysis rate and decreased the initial pyrolysis temperature. Compared with 90% RH, infrared spectra analysis showed that functional groups of UV-A + 90% RH treatment, e.g., –CH, –C=O, and the benzene ring structure, clearly decreased. Straw-degrading bacteria were observed by scanning electron microscopy at the beginning and end of UV-A + 90% RH treatment. Results highlight the role of humidity in the degree of straw biodegradation by filamentous fungi. Straw degradation is accelerated by the combined action of photodegradation and biodegradation under high UV-A irradiation and high humidity.
关键词： Relative air humidity,Biodegradation,TGA,Photodegradation,Ultraviolet-A irradiation,BIOLOG,SEM,ATR-FTIR
更新于2025-09-23 15:23:52