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Manganese dioxide nanoparticles/activated carbon composite as efficient UV and visible-light photocatalyst
摘要： Manganese dioxide nanoparticles/activated carbon (MnO2/AC) composites and manganese dioxide nanoparticles (MnO2 NPs) are prepared through chemical reduction method. Morphological study shows that MnO2 NPs had cylindrical and spherical shape. The morphological study also revealed that MnO2 NPs were well dispersed on AC while neat Mn NPs present both in dispersed and in agglomerated form. The FT-IR study confirms the synthesis of MnO2 NPs. Zetasizer study presented that the Mn NPs had uniform size and below 100 nm in size and had zeta potential of ? 20 mV, which represent its stability in the suspension form. The synthesized Mn/AC composite and Mn NPs were utilized as photocatalysts for the photodegradation of Congo red (CR) dye. The degradation study shows that MnO2/AC composite degraded CR dye more efficiently than MnO2 NPs under UV and normal light irradiation. The efficient degradation of dye by Mn/AC composite is due to the synergistic effect between dye adsorption on AC and rapid photodegradation by supported MnO2 NPs. The results revealed that Mn/AC composite degraded about 98.53% of CR dye within 5 min while MnO2 NPs degraded 66.57% of dye within the same irradiation time. The recycled catalyst also significantly degraded dye which verifies its sustainability. The effect of catalyst dosage and initial dye concentration was conducted. The degradation rate of dye was found drastically faster in tap water (in presence of catalyst), which might be due to the presence of various mineral ions in the tap water.
关键词： Manganese dioxide,nanoparticles,Activated carbon,Photodegradation,Photocatalyst,Congo red
更新于2025-09-23 15:23:52
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Influence of fuel nature on dye adsorption efficiency of solution combustion derived zinc oxide nanoparticles: A comparative study
摘要： The present work demonstrates the use of coffee husk extract as a fuel (otherwise an agro waste) for the synthesis of nano zinc oxide (ZnO) by one step solution combustion synthesis. We also show the comparative studies of coffee husk extract (green fuel) derived nano ZnO (CHZnO) and sugar (chemical fuel) derived nano ZnO (SZnO) as an adsorbent for Congo red dye removal. The adsorption characteristics were investigated with respect to changes in pH, temperature, initial dye concentration, adsorbent dose and contact time. CHZnO exhibited higher adsorption capacity (76 mg/g) compared to SZnO (56 mg/g). The equilibrium adsorption data were analyzed using various isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevith) and thermodynamic parameters. Among the models studied, Langmuir isotherm fitted well with experimental equilibrium data (R2>0.99). Adsorption kinetics was found to follow pseudo-second order with the highest R2 value. Intraparticle or pore diffusion was the major rate controlling step in the adsorption process. The present study demonstrates the potential application of agro-based bio-waste as a novel fuel in the synthesis of nanomaterials for use as efficient adsorbents in water treatment.
关键词： Adsorption,Intraparticle diffusion,Coffee husk extract,nano ZnO,Congo Red
更新于2025-09-23 15:23:52
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Effect of Transition Metal Oxide Doping (Cr, Co, V) in the Photocatalytic Activity of TiO2 for Congo Red Degradation under Visible Light
摘要： Comparative study of Cr, Co or V-doped TiO2 was carried out. The photocatalysts were synthesized via sol-gel method. The results indicated that the dopants of Cr, Co, and V induced anatase to rutile phase transition of TiO2 at different dopant amounts of 1, 4, 2 mol%, respectively. Besides that, the existence of dopant extended the absorption wavelength of TiO2 to visible light region, thus making it a visible-driven photocatalyst. The doped transition metal exhibited different oxidation states on the TiO2 surface. The prepared photocatalysts were tested over photodegradation of Congo Red. Amongst all, Cr-doped TiO2 (3 mol%) was the best photocatalyst attributed to the presence of 45% rutile phase, reduced band gap energy of 2.30 eV and formation of Cr6+, which acted as an electron scavenger to delay the hole-electron recombination.
关键词： photodegradation,congo red,transition metal oxide,Titania
更新于2025-09-23 15:22:29
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Fabrication of raspberry-shaped reduced graphene oxide labelled Fe/CeO2 ternary heterojunction with an enhanced photocatalytic performance
摘要： Herein, we report a raspberry-shaped reduced graphene oxide labelled Fe-CeO2 ternary photocatalyst synthesized via simple hydrothermal method. In order to evaluate structural, morphological, elemental composition and optical properties, resultant photocatalysts were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), energy dispersive x-ray analysis (EDX), photoluminescence (PL) and UV–visible spectroscopy respectively. The photocatalytic efficiency of as-prepared ternary catalyst was investigated by the degradation of congo red dye (CR) in aqueous medium under UV light. The ternary Fe-CeO2/RGO nanocomposite show outstanding photocatalytic degradation performance. The co-ordination and synergistic effect between reduced graphene oxide sheets and redox system of the cerium (Ce4+/ Ce3+) along with iron (Fe3+/ Fe2+) are accountable for the excellent photocatalytic performance of Fe-CeO2/RGO nanocomposite. The reduced graphene oxide sheets and redox systems acts as a trapping sites for photogenerated electrons and thereby significantly reduced the recombination of charge carriers. Moreover, a good reusability and stability suggest that ternary material has a great ability in removal of organic pollutants. Further, this report may offer a new strategy to fabricate and design a material for energy and environmental remediation.
关键词： Raspberry-shaped Fe-CeO2/RGO nanocomposite,Congo red,Photocatalytic degradation
更新于2025-09-23 15:19:57
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Synthesis?of?MgTiO <sub/>3</sub> ?Nanoparticles?for?Photocatalytic?Applications
摘要： Magnesium titanate (MgTiO3) has been successfully synthesized via the sonochemical method by using TiO2 (P25) and Magnesium nitrate (MgNO3)2.6H2O as precursors without any additional phases such as MgTi2O5 and Mg2TiO4. The synthesized nanoparticles were well characterized by optical methods using UV-Vis diffuse reflectance spectroscopy (DRS) and Photoluminescence spectroscopy (PL). The morphology of MgTiO3 nanoparticles is irregular in shape with serious agglomerations were confirmed through SEM analysis. XRD confirms crystal structure and phase purity of MgTiO3 nanoparticles calcined at 700 °C for 2 hours. The calculated band gap energy of MgTiO3 nanoparticles has been found to be 3.05 eV. Using the prepared MgTiO3 nanoparticles, the photocatalytic activities were evaluated by following the degradation of Congo red dye under visible light. Moreover, the influence of various scavengers on the photocatalytic reaction were studied.
关键词： MgTiO3,Scavengers,Congo red,Nanoparticles,Photocatalytic degradation,Sonochemical
更新于2025-09-19 17:15:36
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ZnO/Ag–Ag2O microstructures for high-performance photocatalytic degradation of organic pollutants
摘要： Organic pollutants cause serious impacts on environment. A novel method to synthesize ZnO/Ag–Ag2O microstructures was developed for organic pollutant photocatalytic degradation. The 3D pompon-like Zn(OH)1.68(SO4)0.16·0.58H2O microspheres were firstly synthesized in a creative way by combining reaction in ethanol/water mixing layer and room-temperature self-assembly together. The length of nanosheets on Zn(OH)1.68(SO4)0.16·0.58H2O microspheres was controlled from ~ 0.8 to ~ 4.4 μm successfully. The method reduced both the processing temperature and reaction time compared with conventional ripening, which shortened catalysts’ production cycle, reduced production cost and simplified production condition. It holds great potential for industrial application. As traditional nanocatalysts are not easy to recycle and the residual nanocatalysts are also potential danger to the environment, our microsized ZnO/Ag–Ag2O photocatalysts inherit advantages of both nanoparticles and microspheres with enhanced removal efficiency and excellent recycle ability. Ag–Ag2O nanoparticles in ZnO/Ag–Ag2O microstructures were used to enhance the photocatalytic performance. 83.2% and 96.3% degradation efficiencies of Congo red were achieved by pure ZnO and ZnO/Ag–Ag2O microstructures after 80 min irradiation by UV light. 78.2% and 95.6% degradation efficiencies of methylene blue were achieved by pure ZnO and ZnO/Ag–Ag2O after 40 min under UV radiation. The degradation rate constants by ZnO/Ag–Ag2O microstructures are 0.04056 min?1 for Congo red and 0.07629 min?1 for methylene blue respectively. The ZnO/Ag–Ag2O photocatalyst showed excellent stability and reusability, since it was reused at least 5 times without any extra treatment. The ZnO/Ag–Ag2O microstructures may hold potential for organic pollutant treatments.
关键词： Photocatalytic degradation,Congo red,Self-assembly,3D pompon-like ZnO,ZnO/Ag–Ag2O microstructures
更新于2025-09-10 09:29:36
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Facile Synthesis, Characterization and Enhanced Photocatalytic Activities of NiWO <sub/>4</sub> /Nitrogen Doped Reduced Graphene Oxide Nanocomposites
摘要： In this study, we report the synthesis of NiWO4/nitrogen doped reduced graphene oxide nano composite by one-pot hydrothermal method. The NiWO4 nano particles were dispersed uniformly on graphene sheets. The as prepared NiWO4, NiWO4/5% rGO and NiWO4/N-5% rGO composites were analytically characterized by Powder X-ray diffraction (XRD), Raman spectroscopy, Diffuse re?ectance spectroscopy (DRS-UV), Scanning electron microscopy (SEM) and N2 adsorption–desorption isotherm. The photocatalytic performances of the synthesized composites were evaluated towards the photo degradation of congo red (CR) under visible light radiation. The synthesized catalysts showed remarkable photocatalytic activity in the degradation of CR. Among the catalysts NiWO4/N-5% rGO showed the highest decolourization of congo red (92%) under visible light irradiation. This high activity is attributed to its high e? transport property. Our results provide an invaluable methodology for designing high-performance photo-catalysts for new energy applications.
关键词： Wolframite,Nickel Tungstate,Degradation,Graphene,Congo Red
更新于2025-09-09 09:28:46
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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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Bandgap Tailored TiO2 Thin Films by Addition of SiO2 for Enhanced Photocatalytic Activity against Congo Red under Visible Light Illumination
摘要： Colloidal solutions of SiO2-TiO2 mixed oxides having different SiO2 contents were synthesized by sol-gel technique and thin films were deposited over glass slides by using dip coating technique. The films were subjected to high temperature at 400 °C for growing TiO2 crystals. Energy dispersive X-ray spectroscopy was used to indicate the elements in the films. X-ray diffraction analysis indicated that SiO2-TiO2 films contain only anatase phase. Scanning electron microscopy was used to study the films surface morphology. The SiO2-TiO2 films that were contacted with congo red (5 ppm) and irradiated with visible light showed a high photocatalytic activity. UV spectrophotometry technique was used to monitor the degradation of congo red by the reduction of main absorbance peak at 497 nm. Complete degradation was achieved after 2 h for 3 mol % SiO2-TiO2 thin film.
关键词： Congo red,SiO2,Dip coating,TiO2,Photocatalytic activity
更新于2025-09-04 15:30:14
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ZrO2/Fe2O3/RGO nanocomposite: Good photocatalyst for dyes degradation
摘要： We report a ZrO2/Fe2O3/RGO nanocomposite was synthesized via insitu-hydrothermal method and characterized by X-ray di?raction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), UV–Visible di?use re?ectance spectrophotometer (DRS), Raman, Photoluminescence (PL) and BET analysis to study the structural, morphological and optical properties. FESEM images declares that ZrO2 particles are uniform discs like nanostructure shape with clear facets and narrow size distribution; Fe2O3 were agglomerated, which leads to have completely dispersed with the rGO and forms a ZrO2/Fe2O3/RGO nanocomposite. The elemental composition (Zr, Fe, O and C) of as-prepared ZrO2/Fe2O3/RGO nanocomposite was con?rmed using EDX. FTIR and Raman analysis con?rmed the GO was reduced into RGO during the synthesis of ZrO2/Fe2O3/RGO nanocomposite. The synthesized catalysts were examined for photocatalytic activity by the degradation of Congo Red (CR) and Acetophenone (AP) under visible light illumination, these results clearly prompted that ZrO2/Fe2O3/RGO nanocomposite shows a high photodegradation e?ciency of CR and AP under visible light illumination than ZrO2/Fe2O3, pure Fe2O3 and pure ZrO2.
关键词： Hydrothermal,Raman,Photocatalytic degradation,Congo red and Acetophenone,ZrO2/Fe2O3/RGO nanocomposite
更新于2025-09-04 15:30:14