Ag-doped TiO2 Research Articles

Crystallization and Optical Behaviour of Nanocomposite Sol-Gel TiO2:Ag Films.

Sol-gel spin coating method was employed for depositing TiO2 and Ag-doped TiO2 films. The effects of Ag doping and the annealing temperatures (300-600 °C) were studied with respect to their structural, morphological, vibrational, and optical properties. Field Emission Scanning Electron microscopy (FESEM) investigation exhibited the grained, compact structures of TiO2-based films. Ag incorporation resulted in a rougher film surface. X-ray diffraction (XRD) results confirmed the formation of Ag nanoparticles and AgO phase, along with anatase and rutile TiO2, strongly depending on Ag concentration and technological conditions. AgO fraction diminished after high temperature annealing above 500 °C. The vibrational properties were characterized by Fourier Transform Infrared (FTIR) spectroscopy. It was found that silver presence induced changes in IR bands of TiO2 films. UV-VIS spectroscopy revealed that the embedment of Ag NPs in titania matrix resulted in higher absorbance across the visible spectral range due to local surface plasmon resonance (LSPR). Ag doping reduced the optical band gap of sol-gel TiO2 films. The optical and plasmonic modifications of TiO2:Ag thin films by the number of layers and different technological conditions (thermal and UV treatment) are discussed.

Investigations on the complexation and binding mechanism of bovine serum albumin with Ag-doped TiO2 nanoparticles.

It is essential to study the interactions between nanoparticles and proteins to better understand the biological interactions of nanoparticles. In this study, we studied the protein adsorption mode on the surface of Ag-doped TiO2 nanoparticles (NPs) using a model protein, bovine serum albumin (BSA). The mechanism of binding BSA to the Ag-doped TiO2 NPs was studied by applying fluorescence quenching, absorbance measurements, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy techniques. The strong binding between BSA and Ag-doped TiO2 NPs was confirmed by a high value of binding constant (K = 2.65 × 105 L mol-1). We also studied the thermal stability of BSA in the presence of the Ag-doped TiO2 NPs. Thermodynamic parameters indicated that the adsorption of BSA on the Ag-doped TiO2 NPs was a spontaneous, natural and exothermic process. The effect of Ag-doped TiO2 NPs on the transportation function of BSA was also studied using a fluorescence spectroscopic technique. Fluorescence spectroscopic data suggested the existence of a strong interaction between BSA and the surface of the Ag-doped TiO2 NPs, which indicated that the binding affinities of some selected amino acids in BSA changed. This, in turn, clearly confirms that the Ag-doped TiO2 NPs affect the transportation capability of BSA in blood.

Green synthesis and characterization of TiO2 and Ag-doped TiO2 nanoparticles for photocatalytic and antimicrobial applications

TiO2 and Ag-doped TiO2 nanoparticles were synthesized using lemon grass plant leaf extract via a greener co-precipitation method. Plant biomolecules facilitated nanoparticle production, ensuring stability. Characterization involved XRD, FE-SEM, XPS, FT-IR, EDX, UV-DRS, HR-TEM and UV–Vis spectroscopy analyses, revealing tetragonal and cubic structures for TiO2 and Ag-TiO2, with average sizes of 11.96 and 41.8 nm, respectively. FT-IR confirmed characteristic bands, FE-SEM and HR-TEM analysis reveal that Ag-doped TiO2 nanoparticles primarily form irregular agglomerations, with interplanar spacings of 0.362 nm for the anatase (220) plane and 0.235 nm for the silver (111) plane and EDX determined elemental composition. UV–DRS calculated band gap values (3.3 eV for TiO2, 0.9 eV for Ag-TiO2). Photocatalytic performance against methylene blue dye under sunlight indicated higher degradation by Ag-TiO2 (96.96 %) than TiO2 (77.77 %). Antimicrobial testing showed superior activity of Ag-TiO2 over TiO2.

Simulated sunlight-driven photocatalytic activation of peroxydisulfate by core–shell Ag@SiO2/TiO2 nanocomposite for efficient methyl orange degradation

Herein, core–shell Ag@SiO2/TiO2 nanocomposites were synthesized and applied to activate peroxydisulfate (PDS) for wastewater purification. The Ag core and Ag-doped TiO2 shell were obtained by stober method and calcination method. The dispersion degree and size of Ag in TiO2 would influence the oxygen vacancy. Ag enhanced the visible absorption of TiO2 and activated PDS. Improved degradation performance was attributed to enhanced PDS activation by photogenerated e−, which separated h+and thus promoted methyl orange(MO) degradation. Reactive oxidative species were verified under dark and light conditions via quenching experiments and electron paramagnetic resonance tests, demonstrating SO4•–, h+, O2•–, and1O2were formed in light,whereasSO4•–, •OH, O2•–, and 1O2were responsible for MO degradation under dark conditions. The Ag@SiO2/TiO2/PDS/light system showed selectivity for removal of cationic dyes (e.g., methylene blue and malachite green) through adsorption and photocatalysis, whereas anionic dyes (e.g., MO) were degraded by photocatalysis alone. Besides, we found excess adsorption of micropollutant onto catalyst may be adverse to the activation of PDS. Therefore, the adsorption of oxidant (such as PDS) onto the catalyst surface would be beneficial for catalytic activation and micropollutant degradation, especially onto active sites. This work aims to provide a new avenue for core-shell structure catalyst synthesis in wastewater purification.

Ultralow-resistance and self-sterilization biodegradable nanofibrous membranes for efficient PM0.3 removal and machine learning-assisted health management

The development of multifunctional nanofibrous membranes (NFMs) that enable anti-viral protection during air purification and respiratory disease diagnosis for health management is of increasing importance. Herein, we unraveled a heterostructure-enhanced electro-induced stereocomplexation (HEIS) strategy to fabrication of poly(lactic acid) (PLA) NFMs enabling a combination of efficient PM removal, respiratory monitoring and self-sterilization. The strategy involved an electro-induced stereocomplexation (EIS) approach to trigger the generation of hydrogen bonds between enantiomeric poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) chains, promoting CO dipole alignment and molecular polarization during electrospinning. This was further enhanced by incorporation of Ag-doped TiO2 (Ag-TIO) nanodielectrics to promote the electroactivity and surface activity, conferring profound refinement of PLA nanofibers (from 460 nm to an ultralow level of 168 nm) and high porosities of over 91 %. Arising from the sustainable generation of plentiful charges based on triboelectric nanogenerator (TENG) mechanisms, the electroactive PLA NFMs exhibited remarkable triboelectric properties even in high-humidity environments (80 %RH), excellent PM0.3 filtration efficiency with an ultralow pressure drop (93.1 %, 31.8 Pa, 32 L/min), and 100 % antimicrobial efficiency against both E. coli and S. aureus. Moreover, a deep-learning algorithm based on convolutional neural network (CNN) was proposed to recognize various respiratory patterns. The proposed strategy confers the biodegradable NFMs an unusual combination of ultralow-resistance air purification and machine learning-assisted health management, signifying promising prospects in environmental protection and personal healthcare.

Preparation and antibacterial activity of Ag-doped TiO2 coating on the porous surface of aluminum

Aluminum (Al) and its alloys have been widely used in daily life, but the absence of antibacterial properties makes them potential vectors for bacterial transmission. In this study, an Ag-doped TiO2 coating was successfully prepared on the porous surface of etched Al foil using the sol-gel method. The results indicated that the porous layer allowed the gel to permeate through the holes, thereby forming an interface carrying these antibacterial agents with a thickness of about 10 μm. The Ag dopant promoted the transformation of titania from rutile to anatase during the calcination process, with the rutile being absent when the atomic ratio of Ag to Ti reached 0.10. Meanwhile, the doped Ag+ was thermally decomposed into metallic Ag0. As a result, doping Ag enhanced the photocatalytic efficacy of TiO2 coating. Moreover, the antibacterial rate of this coating against Escherichia coli and Staphylococcus aureus under dark conditions could reach more than 99%, and the corrosion resistance of the Al foil was also slightly improved by it.

Functionalization of Artwork Packaging Materials Utilizing Ag-Doped TiO2 and ZnO Nanoparticles.

Most of the artworks stored in museums are often kept in inappropriate climatic and environmental conditions that facilitate the formation and growth of microorganisms, such as fungi, which are responsible for many types of biodegradation phenomena. To mitigate and prevent these deteriorative processes, functionalized packaging materials can be used for the storage and handling of artworks. The aim of this study was to develop a potential anti-biodeterioration coating suitable for packaging purposes. TiO2 and ZnO doped with different amounts of Ag (0.5 wt%, 1 wt%, and 3 wt%) were synthesized and dispersed in polyvinyl alcohol (PVA) and acrylic resin (Paraloid B72), then applied on different types of packaging materials (cellulose and the high-density spunbound polyethylene fiber Tyvek®, materials that are frequently used as packaging in museums). Analytical investigations (SEM/EDS, Raman, FTIR, and XRD) were employed to assess dispersion on the packaging material. Furthermore, resistance against biodeteriogens was assessed using Cladosporium sp., a bioluminometer, to define the biocidal efficacy.

Enhanced removal of pesticide micropollutant and bacteria using solar light-assisted Ag-doped TiO2: prospects for environmental and health impacts.

Pesticide micropollutants like 4-chlorophenol (4CP) and E. coli bacteria represent a substantial hazard, impacting both the environment and human health. This study delves into the effectiveness of Ag-doped TiO2 (Ag@TiO2) in removing both 4CP and E. coli. Ag@TiO2 has demonstrated remarkable effectiveness in removing 4CP under both solar and visible light conditions, earning degradation efficiencies of 91.3% and 72.8%, respectively. Additionally, it demonstrates outstanding photodegradation efficiency for 4CP (98.8%) at an initial concentration of 1mgL-1. Moreover, Ag@TiO2 exhibited substantially higher removal performance for 4CP (81.6%) compared to TiO2 (27.6%) in wastewater. Analysis of the radicals present during the photodegradation process revealed that ·O2- primarily drives the decomposition of 4CP, with h+ and ·OH also playing significant roles in the oxidation reactions of the pollutant. Interestingly, even under dark conditions, Ag@TiO2 exhibited the capability to eliminate approximately 20% of E. coli, a percentage that increased to over 96% under solar light. In addition, the prospects for environmental and health impacts of utilizing Ag@TiO2 for pesticide micropollutant removal and bacteria were discussed.

Anticancer and Photocatalytic Activity of Ag-doped TiO2 Nanoparticles Synthesized Using Carica papaya Leaf Extract

Anticancer and Photocatalytic Activity of Ag-doped TiO2 Nanoparticles Synthesized Using Carica papaya Leaf Extract

Photocatalytic self-cleaning and antibacterial activity of modified wood by Ag doped TiO2 nanoparticles

The use of nanoparticles has attracted widespread attention in surface science to improve the characteristics of substrates such as thermal stability, corrosion resistance, self-cleaning, and antibacterial effects. Nonetheless, porous materials like wood have received limited attention due to their inherent absorbency. This study aims to evaluate the antibacterial and photo-activity of modified wood employing Ag-doped TiO2 coating applied on the wood surface. The main characteristics of the modified wood were measured through XRD, SEM, AFM, TGA, and DRS analysis to determine structure and crystallinity, shape of particles, physical modifications of the wood surface, degradation rate, band gap alterations, and light absorbance, respectively. Methylene blue indicator witnessed a photo-degradation rate of 90 percent under UV irradiation after 21 h. This rate was observed at around 38 percent under irradiation of visible light. All in all, the modified wood underwent less color change whereas the parent wood witnessed a major change regarding its color. The antibacterial properties of wood were also measured. Two bacterial infections, S. Aureus and E. Coli, were employed for the following experiments. The results illustrated that the coating was able to reduce the amount of colonization and adhesion of E. Coli by 50 % and S. Aureus to zero.

Structural and optical properties of highly Ag-doped TiO2 thin films prepared by flash thermal evaporation

The present study investigates the structural and optical properties of silver (Ag)-doped titanium dioxide (TiO2) thin films prepared via flash thermal evaporation using TiO2 and Ag powders mixture at various mass ratios. The crystallinity and surface morphology of the films were studied by varying the percentage of Ag content. Structural properties were characterized using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM), while optical properties were assessed through optical transmission spectra analysis. Results indicate that Ag doping enhances crystallinity, as evidenced by XRD and Raman spectroscopy, and induces surface plasmon resonance (SPR) absorption attributed to Ag nanoparticles. SEM micrographs reveal agglomerated silver particles on the film surface, confirming Ag diffusion during annealing. Surface analysis through Secondary Ion Mass Spectrometry (SIMS) measurements illustrated the diffusion of Ag within the TiO2 samples and its subsequent accumulation at the surface. We have suggested that the crystallization observed in the evaporated TiO2-Ag thin films may primarily result from the thermal diffusion of Ag metal rather than the annealing process alone. Optical transmission spectra demonstrate a shift in the absorption edge towards the visible region with increasing Ag concentration, indicating enhanced light absorption properties.

Biogenic synthesis of Ag-doped TiO2 photocatalyst using citrus paradisi extract for solar trigged degradation of methylene blue

The world has witnessed substantial deterioration of water resources by different effluents. The most reported among effluents that have caused damage to the water resources are azo dyes that need to be expelled by most efficient techniques such as photocatalysis. This specific study has focused on the synthesis and augmentation of TiO2 for the degradation of methylene blue (MB). In this work TiO2 was synthesized by biogenic route using the extract of Citrus paradisi and the synthesized metal oxide (TiO2) was doped with Ag to escalate the photocatalytic degradation of MB. The synthesized biogenic photocatalyst was characterized by employing XRD and FTIR techniques, which confirms the purity of TiO2. The stability of Ag-doped TiO2 photocatalyst was investigated by performing Zeta-potential and the surface morphology was studied thorough FE- SEM. The photocatalytic efficiency of the photocatalysts were evaluated using UV-vis-Spectroscopy. The XRD analysis confirmed the phase purity of synthesized TiO2 and Ag-doped TiO2. The presence of functional groups associated with the TiO2 and Ag-doped TiO2 were also observed through FTIR. The developed photocatalysts via biogenic route were tested for the degradation of MB that exhibited 56.38% for TiO2 and 85.55% Ag-TiO2 in 120mins respectively.

Ag-doped TiO2 with Tuneable Ag⁰ and Ag+ for Enhanced Photocatalytic Degradation of RR4 Dye

Ag-doped TiO2 with Tuneable Ag⁰ and Ag+ for Enhanced Photocatalytic Degradation of RR4 Dye

Evaluation of antifungal activity of visible light-activated doped TiO2 nanoparticles.

Titanium dioxide (TiO2) is a well-known material for its biomedical applications, among which its implementation as a photosensitizer in photodynamic therapy has attracted considerable interest due to its photocatalytic properties, biocompatibility, high chemical stability, and low toxicity. However, the photoactivation of TiO2 requires ultraviolet light, which may lead to cell mutation and consequently cancer. To address these challenges, recent research has focused on the incorporation of metal dopants into the TiO2 lattice to shift the band gap to lower energies by introducing allowed energy states within the band gap, thus ensuring the harnessing of visible light. This study presents the synthesis, characterization, and application of TiO2 nanoparticles (NPs) in their undoped, doped, and co-doped forms for antimicrobial photodynamic therapy (APDT) against Candida albicans. Blue light with a wavelength of 450nm was used, with doses ranging from 20 to 60J/cm2 and an NP concentration of 500µg/ml. It was observed that doping TiO2 with Cu, Fe, Ag ions, and co-doping Cu:Fe into the TiO2 nanostructure enhanced the visible light photoactivity of TiO2 NPs. Experimental studies were done to investigate the effects of different ions doped into the TiO2 crystal lattice on their structural, optical, morphological, and chemical composition for APDT applications. In particular, Ag-doped TiO2 emerged as the best candidate, achieving 90-100% eradication of C. albicans.

Improving the Performance of Titanium Oxide Nanocomposites as NO2 Gas Sensors for Optimum Sensitivity

In this study, we investigate the performance improvement of titanium oxide (TiO2) nanocomposites as NO2 gas sensors for optimum sensitivity. The TiO2 nanocomposites were synthesized using a solvothermal method and were modified with different dopants and additives to enhance their sensing properties. The sensing performance of the TiO2 nanocomposites was evaluated in terms of sensitivity, selectivity, response time, and recovery time. The synthesized nanocomposites were successfully characterized using AFM, FTIR, SEM-EDX and XRD techniques. The results showed that the addition of additives such as TiO2/GO, TiO2-Ag/GO and TiO2- Al2O3/GO: TiO2/GO significantly improved the sensing properties of the TiO2 nanocomposites. The Ag-doped TiO2 nanocomposites exhibited the highest sensitivity towards NO2 gas with a very low detection limit. The Al2O3-doped TiO2 nanocomposites showed good selectivity towards NO2 gas compared to other interfering gases and has led to increase in the surface area. In conclusion, the addition of additives and the optimization of the annealing temperature can significantly improve the sensing properties of TiO2 nanocomposites towards NO2 gas. The findings of this study can contribute to the development of highly sensitive and selective NO2 gas sensors for various applications such as environmental monitoring and industrial safety.

Preparation and Properties of Cotton Fabric Photocatalyzed by Ag-Doped Madder-Sensitized TiO2

In this study silver nanoparticles (NP) were grown in-situ on the surface of madder-sensitized TiO2 by an in-situ reduction method using silver nitrate as a silver source and a honeysuckle extract as a reducing agent. Silver doped madder-sensitized TiO2 nanoparticles were then prepared, supported on the surface of cotton fabrics to prepare photocatalytic cotton fabrics with high-efficiency self-cleaning properties and excellent antibacterial properties. transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses showed that elemental Ag NPs were deposited on the surface of the madder-sensitized TiO2, and that Ag-doped madder-sensitized TiO2 NPs were successfully loaded on the cotton fabric surface. The results of UV-Visible diffuse reflectance spectroscopy (UV-Vis-DRS) and Photoluminescence Spectroscopy (PL) showed that Ag-doping could further reduce the band gap of madder-sensitized TiO2 than pure TiO2. The absorption of light in the photocatalytic system was increased, and the recombination of electron-hole pairs was effectively inhibited. Compared with madder-sensitized TiO2 photocatalyzed cotton fabric, the degradation rate of nano-Ag-doped madder-sensitized TiO2 photocatalytic cotton fabric for methylene blue (MB) was increased by 10.66% within 2 h, and the degradation process was in line with the first-order reaction kinetic model. After 5 times of washing, the photocatalytic cotton fabric still had excellent photocatalytic performance. Its antibacterial rates against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) reached 100 and 99.99%, respectively. In addition, it had good wrinkle resistance and UV protection properties, but the cross-linking modification reduced the breaking strength by about 14%.

Ag Doping and rGO Coupling of TiO<sub>2</sub> within Polysiloxane Matrix for the Ecofriendly Development of High-Performance Cotton Fabric

In this work, TiO2 was applied to cotton fabric by a sol–gel-hydrothermal process. A combination of 3-(trihydroxysilyl) propyl methylphosphonate monosodium salt solution (TPMP) and (3-aminopropyl)triethoxysilane (APTES) was used as a matrix to enhance the interfacial interaction between TiO2 and surface of the cotton fibres. During the hydrothermal treatment, silver nitrate (AgNO3) or reduced graphene oxide (rGO) were added to produce Ag-doped TiO2- or rGO-coupled TiO2-coated textiles. The successful application of all investigated components on cotton fabric was confirmed by the analysis of SEM and EDS. The results of UPF determination and self-cleaning activity showed excellent performance of both studied nanocomposite coatings, whereas the use of rGO proved to be better than Ag.

Effect of Ag-doping on morphology, structure, band gap and photocatalytic activity of bio-mediated TiO2 nanoparticles

The production of nanoparticles using biogenic synthesis techniques is becoming more prominent due to its diverse applications. In this research, the extract from mango leaf was utilized to fabricate a green method for producing Ag-doped and undoped TiO2 nanoparticles that is non-toxic, economical, and environmentally favorable. Titanium isopropoxide (TTIP) was used as a precursor for Ag-doped and undoped TiO2 nanoparticle production, where the concentrations of the dopant material silver were 2.5 and 3%. Acquired undoped and Ag-doped TiO2 nanoparticles were characterized using several analytical techniques. The morphological, structural, and photocatalytic activity were evaluated using XRD, SEM, EDX, and UV–Vis spectroscopy. In the XRD analysis, undoped and Ag-doped TiO2 nanoparticles indicated the formation of an anatase phase, but there was no rutile phase. The photocatalytic activity and nanoparticles’ band gap were assessed using UV–Vis spectroscopy. The UV–Vis Spectroscopy also revealed a reduced band gap energy (Eg) of Ag-doped TiO2 nanoparticles than the undoped TiO2 Nanoparticles (NPs). The development of photocatalytic activity and features of the “Red-shift” characteristic was established by the progressive photo-degradation of Methylene Blue (MB). The SEM analysis revealed that Ag-doped TiO2 nanoparticles showed more agglomeration than the undoped sample. The average particle size of undoped TiO2 nanoparticles was 38.33 nm, and the size gradually increased for 2.5% and 3% Ag-doping. Utilizing EDX analysis, the doping of Ag+ in the TiO2 lattice structure was confirmed. We can predict from the findings that utilizing biosynthesized TiO2 nanoparticles can be an excellent option for water purification, dye-sensitized solar cells, photo-degradation process, etc., in the long run.

Efficient and stable immobilization of TiO2-based composite photocatalytic system for separation and purification of organic pollutants in wastewater under solar light

Photocatalytic removal of organic pollutants emerging from untreated industrial and aquaculture wastewater are still limited by catalytic efficiency and stability in practical application. In this study, we report the development of a silicone-immobilized, PEG-assisted Ag-doped TiO2 composite for efficient and sustainable removal of organic pollutants under solar irradiation. Firstly, a silicone-immobilized pristine TiO2 (S-TiO2) photocatalytic system was developed, demonstrating superior and stable removal of the organic pollutant Rhodamine B (Rh B) compared to PVA-TiO2 and dip-coated TiO2. Subsequently, pristine TiO2 was modified with the surfactant PEG, Ag species (Ag2O, Ag3PO4), and synthesized using the hydrothermal method, immobilized on silicone (S-H-PEG/PAgT). The S-H-PEG/PAgT, characterized by SEM, XRD, UV–Vis, and WCA revealed surface roughness, crystalline phase, excellent light absorption in the visible region, a narrow band gap, and hydrophobicity. The S-H-PEG/PAgT showed enhanced catalytic performance than S-TiO2 (Control) in the removal of tetracycline, a representative emerging organic contaminant. Furthermore, it displayed remarkable stability over 10 cycles and practicability in environmental conditions. Mechanism analysis revealed •O2– and h+ as the dominant active species involved in the catalytic reaction. Notably, a synergistic effect of surface hydrophobicity, roughness, and photocatalytic activity contributed to the reduction of pollutants. Therefore, the developed novel solar light driven S-H-PEG/PAgT photocatalytic system shows great promise for practical purification of organics pollutants in wastewater.

Photocatalytically active Ag-doped TiO2 coatings developed by plasma electrolytic oxidation in the presence of colloidal Ag nanoparticles

The plasma electrolytic oxidation process of Ti foil in the presence of a colloidal solution of Ag nanoparticles was used for the synthesis of exceptionally photocatalytically active Ag-doped TiO2 coatings. UV–Vis absorption spectroscopy was applied to follow the changes in the surface plasmon resonance band of the Ag nanoparticles as a function of the Ag:PO43− ratio in a phosphate-based electrolyte solution. Transmission electron microscopy revealed the size of the Ag nanoparticles in the range of 3–12 nm. The XRD patterns of the Ag-doped TiO2 coatings confirmed the crystalline anatase TiO2 phase regardless of the dopant concentration and without metallic Ag or crystalline Ag oxide forms. The typical porous morphology of the Ag–TiO2 coatings was observed by scanning electron microscopy. A significantly improved photocatalytic activity of the Ag–TiO2 coatings in the degradation process of the insecticide lindane (gamma isomer of benzene hexachloride) and test molecule methyl orange compared to pure TiO2 was determined using the GC technique. The degradation efficiency of Ag-doped TiO2 coatings is higher for lindane than for methyl orange.