Papers by Keyword: Titanium Dioxide

Abstract: This study aims to evaluate the antibacterial properties of dental resin photopolymer (DRP) specimens modified with additive titanium dioxide (TiO₂) nanoparticles using stereolithography 3D printing technology. TiO₂ known for its excellent biocompatibility, making it a promising additive for enhancing bacterial resistance. Specimens were fabricated with varying compositions of TiO₂ and characterized for surface morphology using Scanning Electron Microscopy (SEM). Antibacterial activity was assessed against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) using Kirby-Bauer disc diffusion method. SEM analysis revealed that TiO₂ particles were relatively well-dispersed on the matrix surface. Antibacterial testing showed the formation of inhibition zones, particularly in sample with composition 5%wt TiO₂, indicating increasing antibacterial performance. The activity was more pronounced against S. aureus, attributed to its less complex cell wall structure and more susceptible to reactive oxygen species (ROS) generated by TiO₂ photocatalytic conditions. These findings suggest that TiO₂-modified DRP has strong potential as an antimicrobial dental restorative material fabricated through SLA-based 3D printing.

Abstract: Ag@TiO₂ core-shell nanoparticles (NPs) were synthesized through an environmentally benign, two-step method utilizing Aloe vera extract as a natural reducing and capping agent. Structural and morphological characterization via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) confirmed the successful formation of spherical core-shell structures with a size range of 10-40 nm. Optical analysis revealed a wide bandgap of 4.8 eV, indicative of quantum confinement effects. While electrokinetic measurements suggested moderate colloidal stability (zeta potential near 0 mV), the nanoparticles exhibited potent, strain-dependent antimicrobial activity. Notably, they demonstrated superior efficacy against Gram-positive Staphylococcus epidermidis (32 mm inhibition zone) compared to Gram-negative Escherichia coli (21 mm inhibition zone). This green synthesis route presents a sustainable strategy for producing antibacterial nanoparticles with enhanced activity against Gram-positive pathogens.

Abstract: Continuous emissions of carbon dioxide (CO₂) into the atmosphere brought several environmental problems. Photoconversion of CO₂ not only can produce value-added products (i.e. methanol) but also aim to reduce the environmental problems caused by CO₂. The present work demonstrates the preparation of N-Bi co-doped carbon quantum dots/titanium dioxide (N-Bi co-doped CQDs/TiO₂) as a visible-light driven photocatalyst for the photoconversion of CO₂ to methanol. Hydrothermal-synthesized N-Bi co-doped CQDs were incorporated into TiO₂ nanoparticles through facile mixing method. The loading of CQDs in TiO₂ matrix resulted in a decrease of band gap to 2.75 and 2.65 eV for N-CQDs and N-Bi CQDs, respectively. Gas chromatography equipped with flame-ionization detection (GC-FID) analysis showed a methanol yield of 17 µmol/gcat from the photoconversion experiment using N-Bi-CQDs/TiO₂ photocatalyst composite. The performance of composite was assigned to the loading of N-Bi co-doped CQDs, which reduced the electron-hole recombination in TiO₂. Doping of N-Bi played an important role in localizing the photogenerated electron-holes, essentially enhancing the electron transfer at the CQDs/TiO₂ interface. Thus, our work could provide insight into the application of CQDs-based photocatalysts in the visible-light driven photocatalytic conversion of CO₂ to value-added products.

Abstract: TiO₂ coated plastic optical fiber is developed for ethanol vapour detection. The detection based on intensity modulated evanescent wave fiber optic sensors. The cladding of POF fiber is etched by using acetone and distilled water. TiO₂ solution is prepared by dissolved the TiO₂ pellet powder in isopropanol and stir it by using ultrasonic homogenizer. The optical properties of TiO₂ is characterized by using UV-Vis spectrophotometer. The performance of coated fiber under ethanol vapour concentration range from 1000 ppm to 5000 ppm is examined. The penetration depth, response of the sensor and the sensitivity of coated fiber is observed transiently. The penetration depth of the TiO₂ coated fiber is 32.96 nm to 35.52 nm with sensitivity of 0.001 µW/% and slope linearity of 93.75 %.

Abstract: We have studied the impact of nanosized grains of copper oxides, grown by atomic layer deposition (ALD), on photocatalytic activity of thin titanium dioxide (TiO₂) films under visible-light irradiation. The size of grains and the crystal phase of copper oxide were controlled by the number of ALD deposition cycles. The x-ray diffraction and x-ray photoelectron measurements revealed preferential formation of CuO for a small number of deposition cycles, while Cu₂O forms preferentially for a larger number of cycles. The photocatalytic efficiency of pristine TiO₂ has been enhanced for copper oxide/TiO₂ structures in which the nanosized copper oxide grains do not cover the entire TiO₂ surface. At the same time, the large increase of the current measured across the copper oxide/TiO₂ structures is consistent with the charge transfer from copper oxide grains to TiO₂, essential for the observed increase of photocatalytic activity.

Abstract: In this study, black phosphorus (BP) was prepared via the high-energy ball milling method, and two-dimensional (2D) BP was further fabricated using the liquid-phase stripping approach. Nano TiO₂ was synthesized via the sol-gel method, and it was combined with black phosphene through N, N-dimethylformamide (DMF) medium by a straightforward solution mixing process to produce BP/ TiO₂ composite photocatalyst. Subsequently, spectrophotometric analysis, X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM) were conducted. The band gap of BP was calculated using the Tauc plot method. The results revealed that the values are 1.06 eV and 1.23 eV, corresponding to the band gap emissions of four-and three-layer BP band gap emission, indicating the successful preparation of few layers of black phosphorus. The HRTEM analysis demonstrated that the BP/ TiO₂ composite photocatalyst formed a relatively stable crystalline state.

Abstract: The dust accumulation and dirt particles always degrade the transparency of glass, later hampers its various applications such as photovoltaic panels, building glass, and car-windshield. In this study, the hydrophilic self-cleaning coatings have been developed by using the nanocalcium Carbonate particles (nanoCaCO₃) and hydrophilic micro-titanium dioxide particles (µ-TiO₂). The presence of oxide groups, CO^-3 and TiO^2- forms a strong attraction of glass to polar water molecules. At the weight ratio of 1: 1 in the CaCO₃ to TiO₂ mixture, it forms a great hydrophilic property in which the water contact angle (WCA) of coated glass has been recorded as low as 11.46 ±0.85°. The coated glass also showed high transparency in UV and Visible regions. The optical transmission of coated glass was above 89% at the wavelength of 300-400nm and above 97% at the wavelength of 400-800nm. Due to its hydrophilic property, the coated glass is capable of removing the dust particles away via the water stream. The hydrophilic coating spontaneously forms the water-thin film after contact with coated glass without the presence of UV light.

Abstract: Mild steels were the most frequently used materials in industries and factories since it possesses unique properties but due to weak environmental changes, these cause deterioration and corrosion to the materials’ surface. To prevent such, protective coatings were applied to protect against corrosion in which by incorporating titanium nanoparticles in polyurethane coatings. Titanium nanoparticles were synthesized using titanium butoxide as a precursor. The obtained nanoparticles were used as an inhibitor mixed with coconut oil-based polyurethane polyol blend against the corrosion on mild steel of 3.5% of sodium chloride solution which has been investigated using the Tafel polarization technique. The polarization curves of the corrosion potential for bare mild steel, along with different amounts of titanium nanoparticles coating, exhibit a positive shift. This shift indicates that the coating film effectively reduces the transport path for the corrosive solution, providing a protective barrier against corrosion. This observation is further supported by the results of the adhesive strength test, which demonstrates that the attachment of the coating films to the metal increases with higher amounts of titanium nanoparticles. This indicates improved adhesion and a stronger bond between the coating and the substrate, enhancing the overall corrosion resistance. The increase of contact angle test confirms the improvement of the coating’s hydrophobicity with the addition of titanium nanoparticles. This suggests that the coating repels water more effectively, further contributing to its protective properties against corrosion. Results also show that the addition of 4wt% of titanium nanoparticles has better anti-corrosion properties than the PU CCP alone, and 0.5, 1.0, and 2.0wt% of titanium added.

Abstract: The synthesis of glycerol carbonate from glycerol has garnered significant research attention because of its wide application in the lithium-ion battery and pharmaceutical industries. This study summarizes the catalytic transformation of glycerol to glycerol carbonate using Na and K titanate nanotubes as catalysts. We report the synthesis of Na and K titanate nanotubes catalyst by a simple co-precipitation route and investigate their catalytic activity in the transesterification of glycerol. The physicochemical properties of the Na and K titanate nanotubes catalyst were successfully studied by CO2-TPD and XRD. The designed catalyst possesses high catalytic efficiency and stability in the transesterification reaction of glycerol. Based on its surface area and basicity, several experiments were performed, and it was observed that under optimized conditions (i.e., 5 wt.% catalyst loading, 5:1 molar ratio of DMC to glycerol, 90 °C, and 90 min), the highest conversion of glycerol was achieved, 92.6% glycerol carbonate. The high thermal stability and recyclability make it an efficient heterogeneous catalyst for the synthesis of glycerol carbonate.

Abstract: Drying process are important in many areas in the agriculture and food sectors, including increasing shelf life, improving transportability by reducing product weight or adding value to products. However, the main problem in the drying process is the relatively high energy consumption. Therefore, the development of energy-saving dryers is necessary. Based on the above reasons, this research aims to study the performance enhancement of heat pump dryers using R32 refrigerant by using heat recovery and nanofluid. The heat that is exhausted from the refrigerant by a heat exchanger. In this work, a Nano titanium dioxide (Ti₂O₃) was selected. Pork was dried under the conditions of drying temperature of 45, 50 and 55 °C and water flow rate in the heat exchanger at the front of the drying chamber of 2, 3 and 4 L/min. Criteria for evaluating heat pump dryer performance include drying rate, specific moisture extraction rate, specific energy consumption, heat pump dryer performance coefficient compared to heat pump dryers without nanofluid. The results showed that increasing the drying temperature and water flow rate in heat exchanger increased the drying rate, power and specific moisture extraction rate in the heat pump dryer using nanofluid. Whereas, the specific energy consumption was lower than the case without nanofluid. Increasing the drying temperature and the water flow rate in the heat exchanger had relatively little effect on the coefficient of performance (COP) of the heat pump dryer. Moreover, the study found that the coefficient of performance of heat pump dryer with nanofluid was in the range of 4.33 - 4.42.