Ag-TiO2 Nanoparticles Research Articles

Novel Ag-Doped- Poly (aniline-co-pyrrole)/Titanium-Dioxide Nanocomposite Sensor Material for Ammonia Detection in Spoiled Meat

Silver-doped poly(aniline-co-pyrrole)/titanium dioxide (Ag-doped PANI-PPy/TiO2) conducting copolymer-based nanocomposite ammonia gas sensor was synthesized through in situ chemical oxidative polymerization by taking different amounts (4%, 5%, 6%, 7%, and 8%) of Ag-TiO2 (1:1 ratio) nanoparticles. Zetasizer; dynamic light scattering, scanning electron microscopy, transmit ion electron microscopy, Fourier transform infrared, X-ray diffraction, UV–vis spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and cyclic voltammetry characterization techniques were used to confirm the real formation of nanocomposites and to evaluate the detection performance of the sensor. The interaction sensitivity of the synthesized nanocomposite sensor with ammonia (NH3) was determined by changing the amounts of nanoparticles. Spectroscopic determination exhibited excellent porosity and a better shift in the absorption bands having band gaps (1.87 eV) for the Ag-doped PANI-PPy/TiO2 nanocomposite sensor than the PANI-PPy copolymer (3.17 eV). Morphological (10 μm) and nanoparticle arrangement studies (20 μm) have shown the uniform allocation of nanoparticles in the copolymer matrix when 6% of Ag-TiO2 (1:1 ratio) was added, while agglomeration occurred when <6% or >6% of Ag-TiO2 was added to the copolymer. A decrease in the amorphous domain of the copolymer with an increase in nanoparticles was observed from the X-ray diffraction and other results.

Enhancement of thermoelectric properties of p-type bismuth telluride bulk composites with Ag-TiO2 nano particles via spray coating and hot deformation process

We aimed to enhance p-type Bi0.4Sb1.6Te3.4 (BST) composite's thermoelectric (TE) properties by minimizing thermal conductivity through hierarchical phonon scattering via nano Ag-coated TiO2 (Ag/TiO2). Hot deformation (HD) was employed to induce multi-scale microstructures in these high-performance p-type TE materials, affecting electrical and thermal transport properties through improved textures and donor-like effects. Our optimization strategy included creating grain boundaries, multiple phonons scattering centers, and introducing high-density lattice defects, significantly reducing lattice thermal conductivity. The combined effects led to a noticeable improvement in the figure of merit (zT) across the temperature range, with all TE parameters measured along the in-plane direction. In the case of the hot-deformed Bi0.4Sb1.6Te3.4 alloy, the maximum zT reached 1.31 at 350 K, while the average zT (zTavg) was 1.17 in the range of 300–400 K, suggesting promising potential for near room temperature TE power generation and solid-state cooling.

Incorporation of TiO2 and TiO2-Ag Nanoparticles in Recycled High-Density Polyethylene: Effect of the Type of Photocatalyst and Incorporation Method on Photocatalytic Activity for the Decomposition of NO

Incorporation of TiO2 and TiO2-Ag Nanoparticles in Recycled High-Density Polyethylene: Effect of the Type of Photocatalyst and Incorporation Method on Photocatalytic Activity for the Decomposition of NO

An antimicrobial acrylic polyurethane coating with TiO2-Ag hybrid nanoparticles

Abstract The purpose of this work is to fabricate the advanced organic antibacterial coating containing the strong photocatalytic nanomaterials. For this purpose, firstly the TiO2–Ag hybrid nanoparticles are synthesized by chemical reduction method. Then, the antibacterial coating based on acrylic polyol, polyisocyanate, and these TiO2–Ag hybrid nanoparticles has been prepared. Mechanical properties show that the optimal content of TiO2–Ag hybrid nanoparticles in the coating matrix is 2 wt%, with its abrasion resistance of 166.2 L/mil; impact strength of 195 kg cm; adhesion of size #1 and relative hardness of 0.78. In addition, FE-SEM analysis shows that the nanocomposite coating has a tight structure with homogeneous dispersion of TiO2–Ag nanoparticles in the polymer matrix. The paint film has good antibacterial activity and has great application prospects. Data from the antibacterial test indicates that in the presence of an acrylic polyurethane coating containing 2 wt% TiO2–Ag, the number of viable Escherichia coli decreased from 3.4 × 105 CFU/ml to 1.5 × 102 CFU/ml after 24 h of culture.

High-performance Ag-TiO2 nanoparticle composite catalyst synthesized by pulsed laser ablation in liquid: properties, mechanism and preparation studies

Precious metal doping can effectively improves the catalytic performance of TiO2. In this study, pulsed laser ablation in liquid (PLAL) is employed to integrate preparation with doping and control composite nanoparticle products by adjusting the laser action time to synthesise Ag-TiO2 composite nanoparticles with high catalytic performance. The generation and evolution of Ag-TiO2 nanoparticles are investigated by analysing particle size, microscopic morphology, crystalline phase, and other characteristics. The generation and doped-morphology evolution of composite nanoparticles are simulated based on thermodynamics, and the optimisation of Ag-doped structure on the composite nanomaterials is investigated based on density functional theory. The effect of Ag-TiO2 structural properties on its performance is examined under different catalytic conditions to determine optimal degradation conditions. In this study, the effect of laser ablation time on the doped structure during PLAL is analysed, which is of further research significance in exploring the structural evolution law of laser and composite nanoparticles, multi-variate catalytic performance testing, reduction of photogenerated carrier complexation rate, and expansion of its spectral absorption range, thereby providing the basis for practical production.

Synthesis of Silver‐Doped Titanium Dioxide Nanoparticles by Sol‐Gel and Coprecipitation Techniques: Evaluation of Antimicrobial Activity and Cytotoxic Effects

AbstractTiO2 nanoparticles are effective alternative to the antibiotics. The quick recombination of the photogenerated charges and the inefficient exploitation of visible light remain the major problems limiting their large‐scale applications. Modifying the TiO2 with Silver that acting as an electron trap, plays an important role in reducing the recombination of TiO2 charges and shift its photo‐response to the visible light region. The present work aims to synthesize AgTiO2 nanoparticles using sol‐gel and coprecipitation methods and evaluating the antimicrobial behavior of them. Also, to find the optimal conditions based on the anatase phase of TiO2 due to its higher antimicrobial activity than the rutile form. Among Ag‐TiO2 nanoparticles obtained, the one prepared by sol‐gel method at 450 °C and PH=8–8.5 exhibits the best antimicrobial property. AgTiO2 nanoparticles have been characterized by means X‐ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR),scanning electron microscope (SEM), ζ‐potential, dynamic light scattering (DLS) that showing promising results. Zeta potential values −103 mV has been reported that is considered as a stable colloidal suspension system that prevents nanoparticles aggregation. Antimicrobial behavior of them were evaluated using Diffusion (Agar disk‐diffusion), Dilution (MIC) and Bacterial colony counting methods and diameter of the inhibitory zone 15 mm and minimum inhibitory concentration 5 mg/ml was observed.Colony count results indicated that AgTiO2 able to kill bacteria at the lowest concentration of 5 mg/ml. Outcomes of MTT assay (measure cell cytoxicity) suggesting the absence of toxicity in living Hfff cells (as a normal human fibroblast) while surviving L929 cells (as a cancer cell line originated from mouse fibroblast cells). After 24 and 48 h incubation from 100 % to 77.3 % and 57.2 % was reduced respectively. This indicates that Ag/TiO2 nanoparticles act as a anticancer drug and have inherent selective toxicity nature towards cancer cells while posing no effect to normal cells. AgTiO2 nanoparticles are synthesized using sol‐gel and coprecipitation methods. The sample prepared by the sol‐gel method at a temperature of 450 °C and pH=8.5, which corresponds to the anatase phase of TiO2 synthesis, shows the best antimicrobial properties and acts as an anticancer drug with inherent selective toxicity nature towards cancer cells while posing no effect on normal cells.

Heat transfer in hybrid nanofluid flow between two coaxial cylinders

This study intends to investigate hybrid nanofluid flow between two permeable cylinders in the presence of thermal radiation and heat generation. The numerical solutions are obtained using the finite difference method. The influence of nanoparticle fraction, porous medium, radiation, heat generation, and angular frequency on the velocity, temperature, and Nusselt number are presented using graphs and tables. It was observed that the maximum velocity was attained by TiO2/water nanofluid, whereas the highest temperature distribution is observed in TiO2-Ag/water. Furthermore, the Nusselt number of the fluid increased by 17.5%, 19.7%, and 21.7% when TiO2, TiO2-Ag, and Ag nanoparticles were added to it, respectively.

Nanometals incorporation into active and biodegradable chitosan films

This study investigates the effects of incorporating ZnO, TiO2, and colloidal Ag nanoparticles on the antioxidant, antimicrobial, and physical properties of biodegradable chitosan films. The research focuses on addressing the growing demand for sustainable packaging solutions that offer efficient food preservation while mitigating environmental concerns. In this investigation, the physical properties including thickness, water content, solubility, swelling degree, tensile strength, and elasticity of the chitosan films were examined. Additionally, the samples were analyzed for total polyphenol content, antimicrobial activity, and antioxidant capacity. Notably, the incorporation of ZnO nanoparticles led to the lowest water content and highest strength values among the tested films. Conversely, the addition of colloidal Ag nanoparticles resulted in films with the highest antioxidant capacities (DPPH: 32.202 ± 1.631 %). Remarkably, antimicrobial tests revealed enhanced activity with the inclusion of colloidal silver nanoparticles, yet the most potent antimicrobial properties were observed in films containing ZnO (E.coli: 2.0 ± 0.0 mm; MRSA: 2.0 ± 0.5 mm). The findings of this study hold significant implications for the advancement of edible biodegradable films, offering potential for more efficient food packaging solutions that address environmental sustainability concerns. By elucidating the effects of nanoparticle incorporation on film properties, this research contributes to the ongoing discourse surrounding sustainable packaging solutions in the food industry.

Facile green synthesis of Ag doped TiO2 nanoparticles using maple leaf for bisphenol-A degradation and its antibacterial properties

Significant advancements are being made in environmentally friendly chemistry through the use of biosynthetic techniques for material synthesis. This study presents a novel and eco-conscious method for producing silver-doped TiO2 (Ag–TiO2) nanoparticles using maple leaves extract.. The synthesis process ingeniously involves combining maple leaf extract with silver and titanium dioxide precursors. Using advanced characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), reveals the characteristic crystal structure, surface complexity and fascinating morphology of the nanoparticles. These results explain the remarkable catalytic ability of Ag–TiO2 nanoparticles (NPs) in effectively degrading BPA under visible and ultraviolet (UV) light irradiation. Ag–TiO2 NPs show the BPA degradation of 94.42% (visible) and 96.83% (UV). In addition, these nanoparticles demonstrate good ability to combat a wide range of threatening pathogenic bacteria. The doping of Ag into TiO2 reveals the enhancement of inhibition growth against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli). This work opens up broad potential for applications in the treatment of BPA-containing wastewater and the development of environmentally friendly antimicrobial materials.

Heat transfer analysis of hydromagnetic hybrid nanofluid (H2O) containing Ag–TiO2 nanoparticles in a slanted triangular enclosure with heated fins

Heat transfer analysis of hydromagnetic hybrid nanofluid (H2O) containing Ag–TiO2 nanoparticles in a slanted triangular enclosure with heated fins

Comparative analysis of entropy generation and heat transfer in a tilted partially heated square enclosure using the finite difference method

PurposeIn recent times, there has been a growing interest in buoyancy-induced heat transfer within confined enclosures due to its frequent occurrence in heat transfer processes across diverse engineering disciplines, including electronic cooling, solar technologies, nuclear reactor systems, heat exchangers and energy storage systems. Moreover, the reduction of entropy generation holds significant importance in engineering applications, as it contributes to enhancing thermal system performance. This study, a numerical investigation, aims to analyze entropy generation and natural convection flow in an inclined square enclosure filled with Ag–MgO/water and Ag–TiO2/water hybrid nanofluids under the influence of a magnetic field. The enclosure features heated slits along its bottom and left walls. Following the Boussinesq approximation, the convective flow arises from a horizontal temperature difference between the partially heated walls and the cold right wall.Design/methodology/approachThe governing equations for laminar unsteady natural convection flow in a Newtonian, incompressible mixture is solved using a Marker-and-Cell-based finite difference method within a customized MATLAB code. The hybrid nanofluid’s effective thermal conductivity and viscosity are determined using spherical nanoparticle correlations.FindingsThe numerical investigations cover various parameters, including nanoparticle volume concentration, Hartmann number, Rayleigh number, heat source/sink effects and inclination angle. As the Hartmann and Rayleigh numbers increase, there is a significant enhancement in entropy generation. The average Nusselt number experiences a substantial increase at extremely high values of the Rayleigh number and inclination.Practical implicationsThis numerical investigation explores advanced applications involving various combinations of influential parameters, different nanoparticles, enclosure inclinations and improved designs. The goal is to control fluid flow and enhance heat transfer rates to meet the demands of the Fourth Industrial Revolution.Originality/valueIn a 90° tilted enclosure, the addition of 5% hybrid nanoparticles to the base fluid resulted in a 17.139% increase in the heat transfer rate for Ag–MgO nanoparticles and a 16.4185% increase for Ag–TiO2 nanoparticles compared to the base fluid. It is observed that a 5% nanoparticle volume fraction results in an increased heat transfer rate, influenced by variations in both the Darcy and Rayleigh numbers. The study demonstrates that the Ag–MgO hybrid nanofluid exhibits superior heat transfer and fluid transport performance compared to the Ag–TiO2 hybrid nanofluid. The simulations pertain to the use of hybrid magnetic nanofluids in fuel cells, solar cavity receivers and the processing of electromagnetic nanomaterials in enclosed environments.

Functionalization of fabrics by Ag-TiO2 Nanoparticles deposition by sol-gel method

Nanotechnology's expanding global applications, especially in textiles, integrate various disciplines within textile engineering. Research primarily concentrates on incorporating nanomaterials, like titanium dioxide and silver, into textile substrates for enhanced functionalities such as self-cleaning, UV protection, and antimicrobial properties. Metal oxide nanoparticles, particularly Ag and TiO2, exhibit remarkable efficacy in combating microorganisms. Sol-gel techniques play a crucial role in surface modification, facilitating better adhesion of nanomaterials and enabling diverse applications in materials science. This study focuses on utilizing silver and titanium nanoparticles for antimicrobial and dirt-repellent properties in lightweight fabrics, showcasing a preliminary step towards uniform incorporation for subsequent evaluation.

Hierarchical nano-/micro-architecture phonon scattering of p-type Bismuth telluride bulk composites with Ag-TiO2 nano particles synthesized by fluidized bed spray coating method

We optimize the thermoelectric (TE) properties by minimizing thermal conductivity utilizing by hierarchical phonon scattering from long to mid wavelength of phonon in p-type Bi0.4Sb1.6Te3.4 (BST) composite with nano Ag-coated TiO2 (Ag/TiO2). We employed an Ag nano particle (20 nm) modulation into TiO2 (500 nm) particles by spray coating method and dispersed in a p-type Bi0.4Sb1.6Te3.4 (BST), giving rise to a hierarchical architecture from nano to micro scale. The nano particle modulation of Ag/TiO2 particles decreases grain sizes of p-type BST matrix. The hierarchical structure of modulating nano particles and small grain sizes of the matrix significantly decreases lattice thermal conductivity due to wide range of wavelength phonon scattering, resulting in the enhancement of thermoelectric performance over a large temperature range. The maximum thermoelectric figure-of-merit zT value reaches to 1.28 for 0.9 wt% Ag/TiO2 modulation doping, which is superior to the other reported ones. The optimized modulating Ag/TiO2 nano-particle dispersion effectively maintains the valence band structure while concurrently mitigating the scattering of charge carriers. Therefore, the nano particle modulation by spray coating method is an effective way to manifest hierarchical architecture from nano to micro-scale phonon scattering, which can be applied in thermoelectric materials design and process.

SYNTHESIS AND STUDY OF Ag-TiO2 NANOPARTICLES FOR APPLICATION IN SELF-CLEANING FABRICS

In this work, the Ag-TiO2 nanocomposite was prepared by sol-gel method and characterized using the Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and UV-Vis spectroscopy. The Ag+/Ti4+ ratio significantly influences the phase transition of TiO2 from anatase to rutile in the nanocomposite: the anatase content decreases from 94.9% to 52.6% as this ratio increases from 1.0 to 4.0 %. The initial Ag+/Ti4+ ratio of 1.0 % was chosen for further research due the highest content of TiO2 in the anatase phase. The nanoparticles are fairly monodisperse and have a spherical shape with an average size of about 18-24 nm. Self-cleaning fabric polyester (PET) was modified successfully with Ag-TiO2 nanoparticles by an immersed method. The nanocomposite of Ag and anatase TiO2 was coated by binder in 100-200 nm in size which coating onto the surface of fabric demonstrated self-cleaning surface with different mechanisms: hydrophobic surface as “lotus leaf” effect, photocatalytic degradation Rhodamine B under solar irradiation. The PET fabric coated with the Ag-TiO2 composite demonstrates stronger antibacterial activity (inhibition zone of 1.3 cm) compared to the fabric coated with TiO2 alone (inhibition zone of 0.8 cm). The results showed that after 6 h of irradiation, the photocatalytic activity of the Ag-TiO2/PET fabric sample is significantly better than that of the TiO2/PET fabric sample. The ability to change from hydrophobic to hydrophilic is especially promising to the interest in self-cleaning surfaces, the textile industry, and environmental cleanup.

3DOM BiOI/TiO2 composites modified by metal Ag with broad spectrum response for photocatalytic degradation and water splitting

In order to improve the photocatalytic performance of TiO2 and expand its absorption range in the visible light region, depositing noble metals, constructing the p-n heterojunction and controlling the morphology were used to modify TiO2. First, the TiO2 photocatalyst with a three-dimensional ordered macroporous structure was prepared by vacuum impregnation combined with calcination, and then the 3DOM Ag/BiOI/TiO2 composites were successfully prepared by the in-situ deposition and photoreduction. The characterization results show that the composites present a large number of open and transparent pore structures. The pore wall is formed by stacking TiO2 nanoparticles, with BiOI and Ag nanoparticles evenly distributed on the surface of the pore wall and in the macroporous framework, which expands the specific surface area of 3DOM TiO2 and provides more active sites for the reaction. The introduction of BiOI and Ag expands the visible light response range and improves the light utilization efficiency. Furthermore, the formation of the Schottky barrier and the internal electric field formed by the p–n heterojunction effectively promotes the interfacial electron transfer and suppress the electron–hole recombination, thereby generating more active species during the photocatalytic process. The experimental results of multi-mode photocatalytic degradation of methyl orange (MO) also show that 3DOM Ag/BiOI/TiO2 photocatalyst has the best photocatalytic degradation activity. In addition, different samples were tested for hydrogen production by photolysis of water under simulated sunlight conditions, and the results show that 3DOM Ag/BiOI/TiO2 has the best hydrogen production ability of photolysis of water. The excellent performance of multi-modal photocatalytic degradation of organic pollution and high photohydrogen production activity in 3DOM Ag/BiOI/TiO2 composites is attributed to the synergistic effect between the introduction of metallic Ag, the unique 3DOM structure, and the p–n heterojunction.

The influence of ultra-probe sonication and polyvinylpyrrolidone on dispersion stability and photocatalytic activity of Ag-TiO2 nanoparticles

The growing use of silver-modified titanium dioxide nanoparticles (Ag-TiO2 NPs) raises environmental concerns. In industrial applications, ultrasonication and surfactant addition are widely employed to improve the efficiency of small amounts of Ag-TiO2 for better dispersion stability. Understanding the stability and dispersion of Ag-TiO2 NPs is crucial. The dispersion stability of Ag-TiO2 NPs is greatly influenced by ultra-probe sonication and polyvinylpyrrolidone (PVP). Ag-TiO2 NP concentrations from 0.1% to 10.0% m/v and PVP concentrations from 0.006% to 0.400% m/v were both used in this study. The effect of ultra-probe sonication presented a high sedimentation height ratio and turbidity below the settling time of 90 min for 0.1%Ag-TiO2 without PVP. A sonication amplitude of 35% and a sonication time of 15 and 30 min showed optimal conditions for good dispersion for 0.1% and 1.0% Ag-TiO2 whereas a sonication amplitude of 20% for 70 s and 140 s was suited for 5.0% and 10.0% Ag-TiO2, respectively. The concentration of PVP was found to be 0.04 times the concentration of Ag-TiO2 for good dispersion. Coordination bonds on the surface of Ag-TiO2 with the carbonyl group served as proof of the chemical adsorption of PVP and Ag-TiO2 NPs. The PVP-coated Ag-TiO2 NPs showed smaller particle sizes and a narrower size distribution than Ag-TiO2. The PVP-coated 1.0% Ag-TiO2 NPs provided lower methylene blue degradation ((5.06 ± 0.76) × 10−3 min−1) under visible light than those without PVP ((9.90 ± 0.74) × 10−3 min−1). These findings advance our understanding about how PVP affects dispersion and photocatalytic activity on Ag-TiO2 and suggest the potential applications as a water pollution coating material.

Energy storage investigation of solar pond integrated with PCM and nanoparticles during winter season in Chennai

Solar energy is a highly regarded renewable energy sources that are attracting substantial attention owing to its potential to alleviate climate change and provide sustainable energy. Solar ponds are one approach to collect solar energy by capturing and storing thermal energy inside a pond. However, the effectiveness of solar ponds has been hampered by reasons such as heat loss, evaporation, and inadequate heat transmission. Researchers have investigated the use of phase change materials (PCMs) and nano-additives to improve the performance of solar ponds in order to overcome these issues.Large amounts of heat can be stored and released by substances known as phase change materials as they transition between two states. By adding PCMs into solar ponds, heat may be retained throughout the day and released at night when the sun is not shining. Alternatively, nano-additives have the potential to enhance the efficiency of a solar pond by improving the heat transfer properties of the fluid present in it.To measure the thermal efficiency of the solar pond, multiple phases of an experiment have been undertaken to establish the degree of thermal efficiency. During the experiment, various parameters were employed to measure and track the temperature variations in the lower convective zone (LCZ) of the solar pond. These measurements were recorded on a daily, weekly, and hourly basis, taking into account the depth of the solar pond as a determining factor. There was also an experiment carried out using micro PCMs and paraffin waxes (PCMs) that were combined into the matrix. In this study, nanoparticles with high thermal conductivity, such as carbon nanotubes (CNTs), and hybrid nanoparticles, such as AgTiO2, were utilized.The solar pond without phase change material (PCM) had an average temperature of 45 °C in the lower convective zone (LCZ). When PCM was added to the solar pond, the maximum temperature in the LCZ increased by 2 °C compared to the previous 24 h. Furthermore, when carbon nanotube (CNT) nanoparticles were incorporated into the solar pond with PCM at the base, the temperature was observed to be 1.3 °C higher compared to a typical solar pond that only used PCM for heat storage. In another scenario, the solar pond with PCM and a combination of CNT and AgTiO2 nanoparticles had an average temperature of 52.5 °C in the LCZ during the first week of observation.

Effects of TiO2, Ag-TiO2, and Cu-TiO2 nanoparticles on mechanical and anticariogenic properties of conventional pit and fissure sealants

The objective of this study was to determine the effects of TiO2, Ag-TiO2, and Cu-TiO2 nanoparticles (NPs) addition on the mechanical and antibacterial properties of resin-based sealants. TiO2, Ag-TiO2, and Cu-TiO2 NPs were characterized with FTIR, Raman, SEM-EDX, TEM, XPS, and XRD, and evaluated for cytotoxicity study. After characterization, the nanoparticles were mixed with commercial pit and fissure sealants (PAFS) in ratios of 1 and 2%. A total of 7 groups were made, control group (PAFS only) and experimental groups (1%-2% TiO2, 1%-2% Ag-TiO2, and 1%-2% Cu-TiO2). ISO standards were adopted to prepare samples for mechanical properties, i.e., compressive strength (CS), flexural strength (FS), and Vickers hardness evaluation. Samples were tested against Streptococcus mutans through an agar well diffusion test. The CS, FS, and Vickers hardness were increased for the Cu-TiO2 group with respect to Ag-TiO2 but values were less compared to TiO2 groups. The highest flow rate was measured in the control group which was 8.16±0.06 mm and 9.17±0.1 mm after 3 and 10 mins respectively. In the agar well diffusion test, the control group showed no zone of inhibition, and the lowest zone of bacterial inhibition was found in PAFS with 1% TiO2 NPs group (13.3 ± 1.5 mm) while the highest was found in PAFS with 2% Ag-TiO2 NPs (21.8 ± 1.7 mm). Cu-doped TiO2 NPs showed more biocompatibility as compared to Ag-doped TiO2. The outcomes were statistically significant for all the mechanical tests and agar well diffusion antibacterial test as the p-value ≤0.05 while for the cytotoxicity test, the p-value >0.05. The TiO2 addition generally improved both the mechanical and antibacterial properties of pit and fissure sealant.

Graphene oxide-coated Ag-TiO2 hybrid nanocomposites for superior photocatalytic activity.

Graphene oxide (GO) has now emerged as one of the most promising materials in different areas such as photocatalysis, adsorption, and energy storage due to its high surface area, unique layered structure, etc. Among various types of precursors, anthracite coal has attracted a lot of attention nowadays as it affords GO a high concentration of sp2 carbons resulting in high conductivity and superior absorbance in the visible region. In this report, we have prepared GO-TiO2 nanocomposites as it is supposed to possess high photocatalytic activity owing to facile electron transmission from the conduction band of TiO2 to the GO surface resulting in a much lower degree of electron-hole pair recombination. To boost the photocatalytic activity further, TiO2 was coated with Ag nanoparticles as well. These hybrid structures were characterized by different analytical techniques, for example, XRD, HR-TEM, SEM, and Raman spectroscopy. The XRD pattern of these composites consists of characteristic peaks corresponding to GO, TiO2, and Ag. The HR-TEM studies confirm the presence of GO layers, cube-shaped TiO2, and spherical Ag nanoparticles. Phenol and 4-nitrophenol have been used as model pollutants to evaluate the photooxidation efficiencies under both UV and visible light irradiation. Under UV irradiation, the GO/Ag-TiO2 ternary nanocomposite shows better photooxidation efficiency (62%) compared to Ag-TiO2 (38%), GO-TiO2 (9%), GO (17%), and TiO2 (8%) toward phenol degradation. The GO/Ag-TiO2 is also having the highest photocatalytic activity toward the removal of phenol under visible light irradiation (34%). The ternary heterostructure (85%) also possesses superior photooxidation activity compared to Ag-TiO2 (44%) and GO-TiO2 (71%) toward the degradation of p-nitrophenol under UV light radiation for 60 min. The above observation reveals that the cooperative effect of Ag, TiO2, and GO is playing a crucial role to result in the high photooxidation activity of the GO/Ag-TiO2 hetero-nanocomposites.

Enhancing Heat Transfer in Blood Hybrid Nanofluid Flow with Ag–TiO2 Nanoparticles and Electrical Field in a Tilted Cylindrical W-Shape Stenosis Artery: A Finite Difference Approach

The present research examines the unsteady sensitivity analysis and entropy generation of blood-based silver–titanium dioxide flow in a tilted cylindrical W-shape symmetric stenosis artery. The study considers various factors such as the electric field, joule heating, viscous dissipation, and heat source, while taking into account a two-dimensional pulsatile blood flow and periodic body acceleration. The finite difference method is employed to solve the governing equations due to the highly nonlinear nature of the flow equations, which requires a robust numerical technique. The utilization of the response surface methodology is commonly observed in optimization procedures. Drawing inspiration from drug delivery techniques used in cardiovascular therapies, it has been proposed to infuse blood with a uniform distribution of biocompatible nanoparticles. The figures depict the effects of significant parameters on the flow field, such as the electric field, Hartmann number, nanoparticle volume fraction, body acceleration amplitude, Reynolds number, Grashof number, and thermal radiation, on velocity, temperature (nondimensional), entropy generation, flow rate, resistance to flow, wall shear stress, and Nusselt number. The velocity and temperature profiles improve with higher values of the wall slip parameter. The flow rate profiles increase with an increment in wall velocity but decrease with the Womersley number. Increasing the intensity of radiation and decreasing magnetic fields both result in a decrease in the rate of heat transfer. The blood temperature is higher with the inclusion of hybrid nanoparticles than the unitary nanoparticles. The total entropy generation profiles increase for higher values of the Brickman number and temperature difference parameters. Unitary nanoparticles exhibit a slightly higher total entropy generation than hybrid nanoparticles, particularly when positioned slightly away from the center of the artery. The total entropy production decreases by 17.97% when the thermal radiation is increased from absence to 3. In contrast, increasing the amplitude of body acceleration from 0.5 to 2 results in a significant enhancement of 76.14% in the total entropy production.