Ag-TiO2 Nanocomposites Research Articles

Investigating bifunctional linker-assisted photocatalytic behavior of Ag–TiO2 nanocomposites

Investigating bifunctional linker-assisted photocatalytic behavior of Ag–TiO2 nanocomposites

Optimization of pullulan production by Aureobasidium pullulans using semi-solid-state fermentation and artificial neural networks: Characterization and antibacterial activity of pullulan impregnated with Ag-TiO2 nanocomposite

This study presents a novel and efficient approach for pullulan production using artificial neural networks (ANNs) to optimize semi-solid-state fermentation (S-SSF) on faba bean biomass (FBB). This method achieved a record-breaking pullulan yield of 36.81 mg/g within 10.82 days, significantly exceeding previous results. Furthermore, the study goes beyond yield optimization by characterizing the purified pullulan, revealing its unique properties including thermal stability, amorphous structure, and antioxidant activity. Energy-dispersive X-ray spectroscopy and scanning electron microscopy confirmed its chemical composition and distinct morphology. This research introduces a groundbreaking combination of ANNs and comprehensive characterization, paving the way for sustainable and cost-effective pullulan production on FBB under S-SSF conditions. Additionally, the study demonstrates the successful integration of pullulan with Ag@TiO2 nanoparticles during synthesis using Fusarium oxysporum. This novel approach significantly enhances the stability and efficacy of the nanoparticles by modifying their surface properties, leading to remarkably improved antibacterial activity against various human pathogens. These findings showcase the low-cost production medium, and extensive potential of pullulan not only for its intrinsic properties but also for its ability to significantly improve the performance of nanomaterials. This breakthrough opens doors to diverse applications in various fields.

Silver doped anatase nanocomposite: a novel photocatalyst with advanced activity under visible light for waste-water treatment

Anatase is a universal semiconductor photocatalyst; however, its wide band-gap energy limits its entire solar spectrum absorption to only 5%. Anatase could be activated in the visible region via nobel metal deposition. This study reports on the facile synthesis of colloidal mono-dispersed anatase nanoparticles of 5 nm particle size via hydrothermal synthesis. Nobel metals (Silver, Nickel) were deposited on colloidal anatase surface. The photocatalytic activities of Ag–TiO2, and Ni–TiO2 were investigated for the degradation of basic fuchsin dye. Ag–TiO2 nanocomposite demonstrated enhanced adsorption activity in dark, as well as superior photocatalytic. Ag–TiO2 nanocomposite demonstrated enhanced removal efficiency by 70.8% under visible irradiation to virgin anatase. Ag–TiO2 nanocomposite demonstrated enhanced oxygen-lattice with low binding energy using XPS analysis. Ag–TiO2 experienced band gap energy of 2.35 eV compared with 3.2 eV for virgin anatase; this feature could secure enhanced solar absorption. Ag–TiO2 demonstrated excellent photo-degradation efficiency of 88% with 0.3% H2O2 under visible light. Deposited silver could catalyze H2O2 decomposition and could promote free radical generation; Ag–TiO2 nanocomposite is a promising photocatalyst for wastewater treatment applications.

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.

Ag-TiO2 Nanocomposite: An Efficient Heterogeneous and Reusable Catalyst for the Three-Component Synthesis of 1-Amidoalkyl-2-naphthols under Solvent-Free Conditions

Ag-TiO2 Nanocomposite: An Efficient Heterogeneous and Reusable Catalyst for the Three-Component Synthesis of 1-Amidoalkyl-2-naphthols under Solvent-Free Conditions

Hydrothermal Synthesis of Heterostructured g-C3N4/Ag-TiO2 Nanocomposites for Enhanced Photocatalytic Degradation of Organic Pollutants.

In this study, heterostructured g-C3N4/Ag-TiO2 nanocomposites were successfully fabricated using an easily accessible hydrothermal route. Various analytical tools were employed to investigate the surface morphology, crystal structure, specific surface area, and optical properties of as-synthesized samples. XRD and TEM characterization results provided evidence of the successful fabrication of the ternary g-C3N4/Ag-TiO2 heterostructured nanocomposite. The heterostructured g-C3N4/Ag-TiO2 nanocomposite exhibited the best degradation efficiency of 98.04% against rhodamine B (RhB) within 180 min under visible LED light irradiation. The g-C3N4/Ag-TiO2 nanocomposite exhibited an apparent reaction rate constant 13.16, 4.7, and 1.33 times higher than that of TiO2, Ag-TiO2, and g-C3N4, respectively. The g-C3N4/Ag-TiO2 ternary composite demonstrated higher photocatalytic activity than pristine TiO2 and binary Ag-TiO2 photocatalysts for the degradation of RhB under visible LED light irradiation. The improved photocatalytic performance of the g-C3N4/Ag-TiO2 nanocomposite can be attributed to the formation of an excellent heterostructure between TiO2 and g-C3N4 as well as the incorporation of Ag nanoparticles, which promoted efficient charge carrier separation and transfer and suppressed the rate of recombination. Therefore, this study presents the development of heterostructured g-C3N4/Ag-TiO2 nanocomposites that exhibit excellent photocatalytic performance for the efficient degradation of harmful organic pollutants in wastewater, making them promising candidates for environmental remediation.

Plasmon-assisted photocatalysis of organic pollutants by Au/Ag–TiO2 nanocomposites: a comparative study

The treatment of organic pollutants contaminated by wastewater from textile industries is a serious concern around the globe, and several techniques are being employed for its treatment. Among these, the semiconductor nanocomposite (NC)-assisted photodegradation of organic dyes has recently attracted attention. Herein, we report surface plasmon resonance (SPR) enhanced photocatalytic activities of heterogeneous photocatalysts (Au/Ag–TiO2) for wastewater treatment. To synthesize the Au/Ag–TiO2 NCs, TiO2 nanoflakes (NFs) are decorated with spherical-shaped plasmonic Au and Ag nanoparticles (NPs) of average sizes ∼13 and ∼30 nm, respectively, using a simple and cost-effective sol-gel method. In comparison to the pristine TiO2 nanoflakes and Ag–TiO2 NCs, highly stable Au–TiO2 NCs exhibit enhanced photocatalytic activity for the degradation of dye mixture (organic pollutants) under the sunlight. The optical and structural properties have been studied to find the reason behind the enhanced photocatalytic activities in Au–TiO2 NCs. The more degradation efficiency and rate constant in Au–TiO2 NCs are mainly attributed to the broad range absorption of visible light and the effective charge transfer, monitored using photoluminescence and ultrafast transient absorption spectroscopy. The total removal efficiency of organic dyes is 90.62% and the rate constant is 0.043 min−1 in 60 min degradation for Au–TiO2, higher than that of Ag–TiO2 and TiO2. Furthermore, the Stern-Volmer constant (Ksv) estimated from the photoluminescence quenching measurements is found to be significantly higher in the case of Au–TiO2 (2420 L−1) than Ag–TiO2 (1750 L−1), which corroborates the fact that there is more charge transfer in Au–TiO2. We believe that this research may shed light on the physics underlying the enhanced photocatalytic performance and capabilities of Au–TiO2 NCs for the removal of organic pollutants in wastewater.

Optimization of Ag-TiO2 nanocomposite at a low toxicity dose as a self-virucidal disinfectant against COVID-19

Optimization of Ag-TiO2 nanocomposite at a low toxicity dose as a self-virucidal disinfectant against COVID-19

Fabrication of Ag–TiO2 nanocomposite employing dielectric barrier discharge plasma for photodegradation of methylene blue

Ag nanoparticles have been incorporated in TiO2 to form Ag–TiO2 nanocomposite. The purpose was to enhance the photocatalytic activity of TiO2 in visible region. Ag–TiO2 nanocomposites were prepared using Dielectric Barrier Discharge Plasma operated at 14, 16 and 20 kV. XRD depicts the formation of cubic Ag with tetragonal geometry of TiO2. FTIR confirms the presence of Ag–O, Ti–O and Ag–O–Ti vibrations. UV-VIS shows that the TiO2 and pristine AgTiO2 do not have any absorption peaks in visible region. However, for 16 and 20 kV plasma treated samples, an absorption peak in visible region (580–720 nm) is observed. Evolution of this peak is because of the bandgap tuning from 3.15 to 2.31 eV. Ag–TiO2 based Photodegradation of methylene blue under UV, Plasma, and sunlight reveals that 16 kV Plasma treated Ag–TiO2 is the best under sunlight (93%). It is concluded that plasma treatment has activated Ag–TiO2 for photo degradation in the visible region.

One-Pot Synthesis of 1,8-Dioxodecahydroacridines using Ag-TiO2 Nanocomposite as a Mild and Heterogeneous Catalytic System

Abstract:Ag-TiO2 nanocomposite is reported to be an efficient, active, and benign recyclable catalyst for highly efficient synthesis of 1,8-dioxodecahydroacridine derivatives from dimedone, aromatic aldehydes, and several anilines or ammonium acetate in ethanol as a solvent at room temperature in a short reaction time and suitable yield. This catalyst is effortlessly recycled by simple filtration and can be reused up to five times with only a negligible loss in its catalytic effectiveness. Low catalyst loading, cost-effectively mild conditions, non-chromatographic purification of target compounds, excellent atom economy, informal procedure, use of a cheaply accessible nanocomposite catalyst, and recyclability of the catalyst are all significant benefits of this method. AFM analysis is performed to confirm the structure, topography, and morphology of Ag-TiO2 nanocomposite. 1,8-dioxodecahydroacridine derivatives having natural significance possess a wide range of pharmacological activities; for instance, antibacterial, antimalarial, anticancer, and mutagenic properties. In terms of the distinctions between aldehydes and anilines, this approach offers a wide range of applications.

Plasmonic Optoelectronic Memristor Enabling Fully Light-Modulated Synaptic Plasticity for Neuromorphic Vision.

Exploration of optoelectronic memristors with the capability to combine sensing and processing functions is required to promote development of efficient neuromorphic vision. In this work, the authors develop a plasmonic optoelectronic memristor that relies on the effects of localized surface plasmon resonance (LSPR) and optical excitation in an Ag–TiO2 nanocomposite film. Fully light‐induced synaptic plasticity (e.g., potentiation and depression) under visible and ultraviolet light stimulations is demonstrated, which enables the functional combination of visual sensing and low‐level image pre‐processing (including contrast enhancement and noise reduction) in a single device. Furthermore, the light‐gated and electrically‐driven synaptic plasticity can be performed in the same device, in which the spike‐timing‐dependent plasticity (STDP) learning functions can be reversibly modulated by visible and ultraviolet light illuminations. Thereby, the high‐level image processing function, i.e., image recognition, can also be performed in this memristor, whose recognition rate and accuracy are obviously enhanced as a result of image pre‐processing and light‐gated STDP enhancement. Experimental analysis shows that the memristive switching mechanism under optical stimulation can be attributed to the oxidation/reduction of Ag nanoparticles due to the effects of LSPR and optical excitation. The authors' work proposes a new type of plasmonic optoelectronic memristor with fully light‐modulated capability that may promote the future development of efficient neuromorphic vision.

Effect of Heating Rate on the Photocatalytic Activity of Ag–TiO2 Nanocomposites by One-Step Process via Aerosol Routes

Ag–TiO2 nanocomposite films, based of Ag and TiO2 nanoparticles, were fabricated in a one-step aerosol route employing the simultaneous plasma-enhanced chemical vapor deposition and physical vapor deposition systems. The as-fabricated films were subjected to different heating rates (3 to 60 °C/min) with a constant annealing temperature of 600 °C to observe the significant changes in the properties (e.g., nanoparticle size, crystalline size, crystallite phase, surface area) toward the photocatalytic performance. The photocatalytic activity was evaluated by the measurement of the degradation of a methylene blue aqueous solution under UV light irradiation, and the results revealed that it gradually increased with the increase in the heating rate, caused by the increased Brunauer–Emmett–Teller (BET) specific surface area and total pore volume.

Fractional order stagnation point flow of the hybrid nanofluid towards a stretching sheet

Fractional calculus characterizes a function at those points, where classical calculus failed. In the current study, we explored the fractional behavior of the stagnation point flow of hybrid nano liquid consisting of TiO2 and Ag nanoparticles across a stretching sheet. Silver Ag and Titanium dioxide TiO2 nanocomposites are one of the most significant and fascinating nanocomposites perform an important role in nanobiotechnology, especially in nanomedicine and for cancer cell therapy since these metal nanoparticles are thought to improve photocatalytic operation. The fluid movement over a stretching layer is subjected to electric and magnetic fields. The problem has been formulated in the form of the system of PDEs, which are reduced to the system of fractional-order ODEs by implementing the fractional similarity framework. The obtained fractional order differential equations are further solved via fractional code FDE-12 based on Caputo derivative. It has been perceived that the drifting velocity generated by the electric field E significantly improves the velocity and heat transition rate of blood. The fractional model is more generalized and applicable than the classical one.

Solar irradiated selective nitroaromatics reduction over plasmonic Ag-TiO2: Deposition time dependent size growth and oxidation state of co-catalyst

Solar irradiated plasmonic Ag-TiO2 (P25) nanocomposites have proficiently harvested solar energy towards nitroaromatics reduction comparatively to almost irresponsive bare TiO2. p-Nitrotoulene (p-NT) and p-nitrobenzaldehyde (p-NBAL) were potentially reduced to p-aminotoulene (p-AT, 87% and 50%) and p-aminobenzaldehyde (p-ABAL, 70% and 38%) with Ag5-P25 (5 min photodeposition time (PDT)) and Ag30-P25 (30 min PDT) respectively. The focus of this study was mainly on the role of PDT (3–30 min) which was found to be directly co-related with size, distribution and oxidation state of deposited Ag nanoparticles (NPs) over titania surface, responsible for superior photocatalytic activity. HR-TEM images confirmed the average size of Ag nanoparticles to be ∼1–2 nm and ∼7–8 nm for Ag5-P25 and Ag30-P25 respectively. Further, XPS analysis suggested the formation of ternary hybrid (Ag2O/Ag-P25) in case of 5 min PDT whereas only metallic Ag was found to be photodeposited as the times was increased to 30 min.

Antimicrobial biodegradable film based on corn starch/Satureja khuzestanica essential oil/Ag–TiO2 nanocomposites

Biosynthesis of nanoparticles (NPs) using plant extract is an eco-friendly method, in which natural materials are used and is a simple, non-toxic, and environmentally friendly green synthesis. In this study, corn starch (CS) film containing Satureja khuzestanica essential oil (SEO) and Ag–TiO2 nanocomposites (size: nearly 30–60 nm) were prepared and its antimicrobial, morphological, physical, and mechanical characteristics were investigated. Ag–TiO2 nanocomposites with different molar percentages were synthesized by S. khuzestanica extract and based on the best antibacterial results against Gram-negative bacteria (Escherichia coli ATCC 25922 and Salmonella typhimurium ATCC 14028) and Gram-positive bacteria (Staphylococcus aureus ATCC 25923), were chosen to prepare the films. Four types of biodegradable films were provided: simple CS film, the film incorporated with SEO (essence film), the film incorporated with Ag–TiO2 nanocomposites (nanofilm), and nano/essence film. The scanning electron microscopy (SEM) was employed for investigating the morphology of the films. The combined energy-dispersive x-ray spectroscopy with SEM was applied to analyze the near-surface elements. Physical characteristics of the films containing water vapor permeability (%) and their moisture content, mechanical tests, and antibacterial properties were examined. Antimicrobial evaluation of the films revealed a 3–4 log and 6–7 log (CFU ml−1) reduction in S. aureus and E. coli species respectively, compared to the control group. The bio-polymer film incorporated with extracted essential oil of S. khuzestanica and Ag–TiO2 nanocomposites are effective to package foods and can delay chemical, physical, and microbial spoilage.

Effect of thermal annealing on microstructure and optical properties of silver-carbon nanocomposite thin films

We reported a novel and versatile processing for the synthesis of Ag-carbon nanocomposites using the combination of the sputtering and PECVD techniques. The influence of the thermal annealing on the surface morphology, the structure and the optical properties of these films was studied. The effective medium model was used to describe the spectrophotometric measurements. Numerical calculations were allowed determining optical constants. The calculated transition gap Eg was found to vary between 1 and 1.5 eV depending on the annealing temperature. These values are lower than those reported for standard Ag-TiO2 and Ag-ZnO nanocomposites, which is promising for advanced optoelectronic devices.

Synthesis and characterization of Ag–TiO2 nano-composites to study their effect on seed germination

Synthesis and characterization of Ag–TiO2 nano-composites to study their effect on seed germination

Photocatalytic C-H bond activation by surface anchoring of [CoII(Saloph)(His)] complex on Ag-TiO2 nanocomposite

A novel heterojunction plasmonic photocatalyst [Co(Saloph)(His)]/Ag-TiO2 as a nanohybrid material was applied for the photocatalytic activity towards the C-H bond cleavage of alcohols to the aldehyde using different oxidants, O2, H2O2, or TBHP under irradiation of visible-light and NHPI as co-catalyst. It was synthesized by photo-deposition of metallic silver nanoparticles on titanium oxide surface and follow it, modification with cobalt(II) Saloph complex under ultrasonic agitation condition using histidine linker to reach a photocatalyst under 50 nm in size and band gap 2.64 eV. The [Co(Saloph)(His)]/Ag-TiO2 nanohybrid was characterized with EDS, XRD, DRS, FT-IR, PL spectroscopies, FESEM imaging, and BET technique. The size This three-component plasmonic photocatalyst revealed high photocatalytic efficiency with 95% conversion and 99% selectivity in aerobic conditions. The higher photocatalytic performance of [Co(Saloph)(His)]/Ag-TiO2 than the Co(Saloph)/TiO2 and Ag-TiO2 NPs should be related to the localized surface plasmonic resonance (LSPR) of these motives. So, this three-component nanohybrid provides an efficient interfacial electron transfer process through a synergistic effect that allows producing a nanocatalyst, with advantages of stability and fast selective C-H bond activation alcohols at ambient temperature using O2 as an inexpensive environmental friendly oxidant.

Catalytic Reduction of 4-Nitrophenol to 4-Aminophenol using Chitosan Ag-TiO2 Nanocomposite and its Applications in the Removal of Malachite Green by Photodegradation Technique

A simple colloidal processing method was used to synthesize chitosan Ag-TiO2 nanocomposite and its use aimed at the catalytic reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 as reductant. The nanocomposite catalyst was characterized using different technquies and revealed its better catalytic ability than pure TiO2. Since the nanocomposites are readily improved from the solution phase without centrifugation or filtration. The catalytic activity trials were examined by changing the catalyst dose, concentration of NaBH4, amount of nitrobenzene and temperature. The reduction reactions were affected by the temperature of reaction medium and the concentration of NaBH4. The photodegradation conditions were optimized by changing different parameters such as irradiation time, dosage, pH and initial dye concentration.

Green biomimetic synthesis of Ag\u2013TiO2 nanocomposite using Origanum majorana leaf extract under sonication and their biological activities

BackgroundStudies of plant extract-mediated synthesis of nanoparticles is extensively explored and studied in recent time due to eco-friendly, cost-effectiveness and minimal use of toxic chemicals for synthesis. In this study, the synthesis of Ag–TiO2 nanocomposites (NCs) was carried out using Origanum majorana leaf extract under ultrasound irradiation. Origanum majorana leaf extract plays an important role as reducing and capping agent in synthesis of Ag–TiO2 nanocomposites (NCs). The antimicrobial activities of synthesised Ag–TiO2 NCs have been studied against Gram-positive and Gram-negative bacteria. In addition to this, the antioxidant activity of green Ag–TiO2 NCs was also evaluated on the basis of free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS), and hydrogen peroxide free radicals.ResultsGreen-synthesised Ag–TiO2 NCs were successfully characterised on the basis of UV–Vis spectrophotometer, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD), scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM–EDS) and transmission electron microscopy (TEM). The results revealed the spherical shape of nanocomposite with an average size 25–50 nm. The synthesised Ag–TiO2 NCs have showed significant antimicrobial activity against Escherichia coli, Bacillus subtilis and Aspergillus niger in comparison to TiO2 nanoparticles (NPs). The antioxidant evaluation of biomimetic synthesised Ag–TiO2 NCs also exhibited strong activity than TiO2 NPs and comparable to standard.ConclusionGreen-synthesized Ag–TiO2 NCs provide a promising approach that can satisfy the requirement of large-scale industrial production bearing the advantage of low cost, eco-friendly and reproducible.