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Synergistic effects of biomass-derived carbon quantum dots and Cu Co-doping on TiO2 nanocomposite for enhanced visible-light photocatalysis
(2026-12-01)
Zhao, Huali
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Noonuruk, Russameeruk
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Bootchanont, Atipong
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Porjai, Porramain
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Thongpool, Voranuch
The development of sustainable approaches for enhancing the visible-light activity of TiO<inf>2</inf>-based photocatalysts has attracted considerable research interest. In this work, carbon quantum dots (CQDs)-Cu co-modified TiO<inf>2</inf> nanocomposites were synthesized via a hydrothermal method using butterfly pea ( Clitoria ternatea ) flowers as a biomass-derived carbon source. The Cu content was fixed at 1.5 mol% relative to Ti, while the CQDs loading was controlled by varying the butterfly pea precursor concentration from 0.25 to 1.25 g L−1, yielding 1C–Cu–TiO<inf>2</inf>, 3C–Cu–TiO<inf>2</inf>, and 5C–Cu–TiO<inf>2</inf> samples. The prepared materials were characterized by electron microscopy, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, photoluminescence (PL), and X-ray absorption spectroscopy (XAS). High-resolution transmission electron microscopy revealed CQDs with an average size of approximately 4.29 nm and an interplanar spacing of approximately 0.23 nm. All composites retained the anatase TiO<inf>2</inf> phase after Cu incorporation and CQDs modification. Enhanced visible-light absorption was observed and is attributed to the formation of Cu-related sub-band-gap states and the sensitization effect of CQDs. PL analysis showed an emission peak at ∼415 nm under 660 nm excitation, suggesting the presence of upconversion photoluminescence behavior in the CQDs. Conventional PL spectra further suggested reduced charge-carrier recombination in the modified composites. Photocatalytic activity was evaluated through Rhodamine B (RhB) degradation under visible-light irradiation. Among all samples, 1C–Cu–TiO<inf>2</inf> exhibited the highest performance, achieving degradation efficiency of 99.28% within 50 min. The apparent reaction rate constant reached 0.1038 min−1, which was 2.23, 1.96, and 2.90 times higher than those of pristine TiO<inf>2</inf>, Cu–TiO<inf>2</inf>, and 3C–Cu–TiO<inf>2</inf>, respectively. Radical scavenging experiments indicated that •OH and h+ were the dominant reactive species, while •O<inf>2</inf>− also participated in the degradation process. The enhanced photocatalytic performance is attributed to the synergistic effects of Cu and biomass-derived CQDs in improving visible-light harvesting and charge separation, providing an effective approach for developing visible-light-responsive TiO<inf>2</inf> photocatalysts.
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Porous Electrospun Carbon Nanofibers Bearing TiO2 Hollow Nanospheres for Supercapacitor Electrodes
(2024-03-22)
Wongprasod, Suchunya
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Tanapongpisit, Nantawat
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Laohana, Peerawat
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Huyen Nguyen, Thi My
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Van, Hoang Quy
A facile fabrication method was introduced to enhance the specific surface area and porosity of the carbon nanofibers. The carbon nanofibers bearing TiO<inf>2</inf> hollow nanosphere electrodes were synthesized using an electrospinning technique followed by heat treatment. Varying amounts of as-prepared TiO<inf>2</inf> hollow nanospheres were incorporated into the polymer precursor to examine their impact on the electrode enhancement. The electrochemical performance of supercapacitor electrodes composed of carbon nanofibers bearing TiO<inf>2</inf> hollow nanospheres was investigated. Results revealed that the specific capacitance of the bare carbon nanofibers electrode (170 F g-1 at a current density of 0.5 A g-1) was significantly improved upon when embedded with 5 wt % TiO<inf>2</inf> hollow nanospheres of 191 F g-1. Additionally, the carbon nanofibers bearing 5 wt % TiO<inf>2</inf> hollow nanosphere electrodes demonstrated excellent cycling stability, retaining 97% of its initial specific capacitance even after 10000 cycles. Additionally, the electrochemical performance of asymmetric supercapacitors from these electrodes was also demonstrated. These findings highlight the ability of as-prepared TiO<inf>2</inf> hollow nanospheres to improve the efficiency of the carbon nanofibers electrode due to the optimum porosity to the amount of TiO<inf>2</inf> hollow nanospheres in the carbon nanofibers, opening up possibilities for the development of high-performance supercapacitors.
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Influence of Phase Structure of TiO2 Nanoparticles on Resistive Switching Devices
(2024-01-03)
Tunhoo, Benchapol
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Chantarawong, Direklit
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Thiwawong, Thutiyaporn
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Onlaor, Korakot
In this work, the electrical memory properties of a bi-stable device based on the structure of aluminum/poly (9-vinyl carbazole) (PVK): TiO<inf>2</inf> NPs/indium-tin-oxide (ITO) were reported. The effects of the modified phase structural of titanium dioxide nanoparticles (TiO<inf>2</inf> NPs) on the electrical memory characteristics were determined. The TiO<inf>2</inf> NPs were annealed at different annealing temperatures. The physical properties of the annealed TiO<inf>2</inf> NPs were characterized by transmission electron microscope and X-ray diffraction, which revealed the composition and structure of the anatase and rutile phases. Current-voltage measurements showed that the bi-stable characteristics were affected by the phase structure of the TiO<inf>2</inf> NPs. The ON/OFF current ratio of the fabricated device was noted to be approximately 2.06×105 in the case of TiO<inf>2</inf> NPs annealed at 500°C. A theoretical model was used to explain the charge injection mechanisms of the device. Moreover, the temperature dependence and retention-time measurements of the device were demonstrated.
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Characterization and Self-Cleaning Properties of Silk Fabric Coated by Chitosan-Xyloglucan/nano-TiO2 Composite Film
(2024-01-01)
Lampang, Chaiyawat Na
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Sriprom, Pongsert
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Manamoongmongkol, Kanjana
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Assawasaengrat, Pornsawan
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Narkrugsa, Woatthichai
In this study, Chitosan-Xyloglucan encapsulated Titanium dioxide was prepared by in-situ method for coating Silk fabric. FT-IR XRD characterized the functional groups and formation of crystallization of composite film. SEM analysis showed the immobilization of composite film on the surface of silk fabric. The coated silk fabrics were stained with methylene blue, and the stain removal efficiency was evaluated. The results showed that the composite film was deposited onto the silk fabric. The functional groups showed peaks around 1635 to 1636 and 400 to 500 cm-1 that indicate the presence of C=N groups of Chitosan-Xyloglucan and Ti-O groups of TiO<inf>2</inf> on the composite, respectively. The XRD results indicated that the TiO<inf>2</inf> prepared by the sol-gel method was an anatase crystalline structure. The mechanical properties showed the composite film was superior to the Chitosan-Xyloglucan, TiO<inf>2</inf>, and uncoated silk fabric. Finally, the methylene blue degradation capability was investigated. The coated silk fabric has insignificantly removing methylene blue stain than the untreated silk fabric, but it is noticeably repellent to stain.
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The Behavior of Dissolved Gas in Mineral Oil with TiO2 and Three Types of Insulation Paper at 150 Degree Celsius
(2024-01-01)
Jongvilaikasem, Korraya
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Bunlaksananusorn, Chanin
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Vittayakorn, Wanwilai
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Pattanadech, Norasage
The main electrical insulation in oil-immersed transformers is liquid insulation and paper insulation. Liquid insulation is generally used mineral oil. However, improvements in the quality of liquid insulation are continually being made for better efficiency i.e. adding various additives such as inhibitors and nanoparticles. Nanoparticles are a solid substance used in research for many years. TiO<inf>2</inf> is a type of nano that is commonly used in research to increase the efficiency of mineral oil. This research experimented by preparing dry transformer oil mixed with 0.03% TiO<inf>2</inf>. The test vessels consisted of 3 main components: 1) 35 ml of MO with 0.03% TiO<inf>2</inf>, 2) 1 gram of paper with three types of insulation including pressboard, kraft, and diamond dot paper, and 3) two types of coils including copper and aluminum with size 1∗2.5 cm. The sample vessels were aged at 150 C for 72 hours in the vacuum oven. After aging, oil samples were analyzed by dissolved gas analysis (DGA). From the DGA test results, it was found that similar weights of different types of paper produced different gas-generating results.
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PMMA/High-k Self-assembled TiO2 /PMMA Multi-layer Gate Dielectric for P3HT Organic Field Effect Transistors
(2022-01-01)
Inpor, Kroekchai
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Houngkamhang, Nongluck
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Thanachayanont, Chanchana
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Prichanont, Seeroong
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Kayunkid, Navaphun
In this work, a multi-layer structure of poly (methyl methacrylate)/ titanium dioxide/poly (methyl methacrylate) (PMMA/TiO₂ /PMMA; PTP) was proposed as a top-gate insulator for P3HT-based organic field-effect transistors (OFETs). Adding a TiO₂ interlayer as a high dielectric constant (high-k) material into PMMA film enables the modification of the dielectric constant of the multi-layers PTP film. The content of TiO₂ in the PTP film, which can be varied by changing the number of soaking cycles in TiO₂ solution, plays a crucial rule in modifying the dielectric constant of the PTP film. The higher the TiO₂ content used in the PTP film, the higher the dielectric constant of PTP film can be obtained. However, using high TiO₂ content led to a reduction in the dielectric constant of the PTP film due to leakage current induced by the agglomeration of TiO₂. The utilization of the top-gate insulator containing TiO₂ significantly enhanced several P3HT-OFETs characteristics, e.g., an increase in the I<inf>on</inf>/I<inf>off</inf> ratio, and a decrease in the threshold voltage. However, the use of the PTP top-gate insulator with a high content of TiO₂ resulted in regressions in the OFETs characteristics, such as a decrease in carrier mobility and reduction in the I<inf>on</inf>/I<inf>off</inf> ratio. OFETs operating at the optimum conditions of the PTP gate-insulator, with PTP thickness of 225 nm and RMS roughness of 20.0 nm, provided a dielectric constant of 7.13, a threshold voltage of-8.49 V, a saturation mobility of 2.2× 10-4 cm²V-1s-1, I<inf>on</inf>/I<inf>off</inf> ratio of 37.9, and a subthreshold slope of 0.39 V/decade.
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Factors affecting the degradation of linear alkylbenzene sulfonate by TiO2 assisted photocatalysis and its kinetics
(2018-01-01)
Jariyanorasade, Anon
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Junyapoon, Suwannee
This research aims to study photocatalytic degradation of linear alkylbenzene sulfonate (LAS) in synthetic solution and industrial laundry wastewater by UV/TiO<inf>2</inf> process. The structural and surface properties of Degussa P25 TiO<inf>2</inf> powder were measured by X-ray diffractometer (XRD) and Autosorb, respectively. Factors affecting the photocatalytic decomposition i.e. pH, TiO<inf>2</inf> dosage, irradiation time, initial LAS concentration were investigated in a batch reactor. The kinetic of LAS degradation was studied at room temperature. After degradation, byproduct formation was analyzed using GC-MS. The experimental results showed that a dominating crystalline structure of TiO<inf>2</inf> was the tetragonal anatase phase (82.58%). The TiO<inf>2</inf> had a surface area of 77.79 m2/g, a pore size of 14.38 nm in diameter and a pore volume of 0.28 cc/g. It was found that the optimum conditions for photocatalytic degradation of LAS were at initial LAS concentration of 20 mg/L, non-adjust pH (pH 5.5), TiO<inf>2</inf> dosage of 100 mg/L with irradiation time for 60 mins. Under these conditions, the removal efficiency of LAS in the synthetic solution reached 83.20%. The removal of LAS follows the second order kinetic with rate constant of 0.0031 L/mg/min and half-life of 16.13 min. Alkyl long chains, carboxylic acids and aromatic rings were detected as its degradation products. The removal efficiencies of LAS, orthophosphates and COD in industrial laundry wastewater were 51.99±7.36%, 45.98±4.85 % and 16.00±0.00%, respectively.
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Characterization and x-ray absorption spectroscopy of ilmenite nanoparticles derived from natural ilmenite ore via acidassisted mechanical ball-milling process
(2017-09-01)
Phoohinkong, Weerachon
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Pavasupree, Sorapong
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Wannagon, Anucha
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Sanguanpak, Samunya
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Boonyarattanakalin, Kanokthip
In this work activated ilmenite nanoparticles were prepared by chemical-assisted in mechanical ball-milling process from ilmenite ore as starting raw material. The effect of milling process on their phase composition, particle size, surface morphology and local structure were investigated. Phase identification and crystalline structure of ilmenite mineral, milled samples and subsequent leached residues were characterized by x-ray diffraction (XRD). Meanwhile, the distorted octahedral structure and the oxidation state of relevant elements in ilmenite ore and activated ilmenite obtained by different process conditions were analyzed by x-ray absorption spectroscopy (XAS). Particle size and morphologies of the samples were monitored by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Three dominant peaks of TiO2 rutile, FeTiO<inf>3</inf>, and Fe<inf>2</inf>TiO<inf>4</inf> are obviously adulterated in XRD patterns after mechanical milling with water and acid solution when comparing to precursor mineral. However, the contaminated phase of FeTiO3 and Fe<inf>2</inf>TiO<inf>4</inf> was readily decreased by acid-assisted mechanical ball-milling. The enhancement in leaching process of ilmenite residue after milling can be obtained with sulfuric acid. This result suggests that iron contaminated phase could be leached from the sample resulting to the decrease in Fe environment around Ti atom.
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X-ray absorption spectroscopy analysis and magnetic properties of M-doped TiO2 nanoparticles (M=Co, Mn, Ni and Zn) prepared by co-precipitation method
(2017-08-01)
Wattanawikkam, Chakkaphan
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Pecharapa, Wisanu
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Ishihara, Keiichi N.
M-doped TiO<inf>2</inf> nanoparticles (M=Co, Mn, Ni and Zn) were synthesized by co-precipitation method combined with annealing at 500 °C for 2 h. X-ray diffraction (XRD) was used to identify their structural phases. X-ray absorption near edge structure (XANES) was conducted to probe the chemical state and crystal atomic structure of prepared samples. Magnetic properties of all samples were characterized by vibrating sample magnetrometer (VSM). The XRD analyses reveal that all samples crystallize in anatase tetragonal structure with no additional peaks. The XANES spectra exhibit triple pre-edge fingerprint of Ti4+ of oxidation state with six-fold octahedral coordinate structure. Co-, Ni- and Zn- K-edge results indicate that the Co, Ni and Zn ions in M-doped TiO<inf>2</inf> are in 2+ formal oxidation state. Meanwhile, Mn-doped TiO<inf>2</inf> sample contains the different oxidation states of 3+ and 4+. The amount of each oxidation state is confirmed by using linear combination fitting method. The magnetic measurement illustrates the paramagnetic behavior for Co-, Mn- and Ni- doped samples that strongly depend on the doping content and no hysteresis loop is observed in undoped and Zn-doped samples.
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Effect of calcination temperature on structure and photocatalytic activity under UV and visible light of nanosheets from low-cost magnetic leucoxene mineral
(2017-07-01)
Charerntanom, Wissanu
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Pecharapa, Wisanu
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Pavasupree, Suttipan
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Pavasupree, Sorapong
This research has experimentally synthesized the nanosheets from the naturally-mineral magnetic leucoxene under the hydrothermal synthesis condition of 105 °C for 24 h. Magnetic leucoxene was utilized as the starting material due to its high TiO<inf>2</inf> content (70–80%) and inexpensiveness. The characterization of the synthesized nanosheets was subsequently carried out: the crystalline structure, the chemical composition, the shape, the size and the specific surface area, by the X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) specific surface area analysis. The analysis results indicated that the starting magnetic leucoxene is of rutile phase while the synthesized nanosheets are of titanate structure (H<inf>2</inf>Ti<inf>x</inf>O<inf>2x + 1</inf>). After calcination at the temperature range of 300 and 400 °C, the calcined samples demonstrated TiO<inf>2</inf> (B). At 500 and 600 °C, the calcined nanosheets revealed a bi-crystalline mixture consisting of TiO<inf>2</inf> (B) and anatase TiO<inf>2</inf>. At 700–1000 °C, the crystalline structure shows anatase and rutile phase. At 1100 °C, the prepared samples consisted of a mixture of anatase, rutile phase of TiO<inf>2</inf>, and Fe<inf>2</inf>O<inf>3</inf> phase. The synthesized product also exhibited the flower-like morphology with 2–5 μm in diameter, and the nanosheets structure was slightly curved, with 100 nm to 2 μm in width and 1–3 nm in thickness. At 100–200 °C showed sheets-like structure. At 300–1100 °C, the calcined nanosheets became unstable and began to decompose and transform into nanoparticles. The increasing size of nanoparticle decreased the specific surface area of the nanosheets, caused by increasing calcination temperature. Furthermore, the BET specific surface area of the nanosheets was approximately 279.8 m2/g. More importantly, the synthesized nanosheets achieved the higher photocatalytic activity under UV and visible light than did the commercial TiO<inf>2</inf> nanoparticles (JRC-01, JRC-03, ST-01 and P-25).

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