One-Step Synthesis of Ag@TiO₂ Nanoparticles for Enhanced Photocatalytic Performance

Formation of Olive-like TiO2 Nanospheres in a Polymeric Mesh by Sol-Gel Method

Olive-like TiO2 (titanium dioxide), nanospheres compounds were synthesized. Polysaccharide (1-3 linked β-D galactapyranose and 1.4-linked 3.6 anyhdro-α-L-galactopyranose and titanium isopropoxide (IV) was used as a precursor in its formation. The powder sample was evaluated by scanning tunneling microscope, X-ray diffraction pattern, power spectral density, fast Fourier transform, differential thermal analysis, continuous wavelet transform, and isotropy texture analysis. The results demonstrate that these nanospheres can successfully be synthesized in a solution using a polysaccharide network by means of the sol-gel method. The synthesized olive-like TiO2 nanospheres have diameters ranging from 50 nm to 500 nm. The synthesis parameters, such as temperature, time, and concentration of the polysaccharide, were controlled in solution.

A critical review on the recent trends of photocatalytic, antibacterial, antioxidant and nanohybrid applications of anatase and rutile TiO2 nanoparticles

Titanium dioxide nanoparticles (TiO2 NPs) have become a focal point of research due to their widespread daily use and diverse synthesis methods, including physical, chemical, and environmentally sustainable approaches. These nanoparticles possess unique attributes such as size, shape, and surface functionality, making them particularly intriguing for applications in the biomedical field. The continuous exploration of TiO2 NPs is driven by the quest to enhance their multifunctionality, aiming to create next-generation products with superior performance. Recent research efforts have specifically focused on understanding the anatase and rutile phases of TiO2 NPs and evaluating their potential in various domains, including photocatalytic processes, antibacterial properties, antioxidant effects, and nanohybrid applications. The hypothesis guiding this research is that by exploring different synthesis methods, particularly chemical and environmentally friendly approaches, and incorporating doping and co-doping techniques, the properties of TiO2 NPs can be significantly improved for diverse applications. The study employs a comprehensive approach, investigating the effects of nanoparticle size, shape, dose, and exposure time on performance. The synthesis methods considered encompass both conventional chemical processes and environmentally friendly alternatives, with a focus on how doping and co-doping can enhance the properties of TiO2 NPs. The research unveils valuable insights into the distinct phases of TiO2 NPs and their potential across various applications. It sheds light on the improved properties achieved through doping and co-doping, showcasing advancements in photocatalytic processes, antibacterial efficacy, antioxidant capabilities, and nanohybrid applications. The study concludes by emphasizing regulatory aspects and offering suggestions for product enhancement. It provides recommendations for the reliable application of TiO2 NPs, addressing a comprehensive spectrum of critical aspects in TiO2 NP research and application. Overall, this research contributes to the evolving landscape of TiO2 NP utilization, offering valuable insights for the development of innovative and high-performance products.

Multicomponent Photocatalytic-Dispersant System for Oil Spill Remediation

In the present work, the potential application of a fabricated halloysite nanotubes-Ag-TiO2 (HNT-Ag-TiO2) composite loaded with a binary surfactant mixture made up of lecithin and Tween 80 (LT80) in remediating oil spillages was examined. The as-prepared Ag-TiO2 that was used in the fabrication of the HNT-Ag-TiO2-LT80 composite was characterized by X-ray diffraction, Raman spectroscopy, UV-vis and diffuse reflectance spectroscopy, CV analyses, and SEM-EDX. The synthesized composite was also characterized by thermogravimetric analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy. The synthesized composite was active in both the UV and visible light regions of the electromagnetic spectrum. The oil-remediating potential of the as-prepared composite was examined on crude oil, and aromatics and asphaltene fractions of crude oil. The composite was able to reduce the surface tension, form stable emulsions and smaller oil droplet sizes, and achieve a high dispersion effectiveness of 91.5%. A mixture of each of the crude oil and its fractions and HNT-Ag-TiO2-LT80 was subjected to photodegradation under UV light irradiation. The results from the GC-MS and UV-vis analysis of the photodegraded crude oil revealed that the photocatal composite was able to photodegrade the crude oil, aromatics, and asphaltene fractions of crude oil with the formation of intermediate photodegradation products depicting that the HNT-Ag-TiO2-LT80 has a potential as an oil spill remediation material.

Multi-functional silver nanoprism-titanium dioxide hybrid nanoarrays for trace-level SERS sensing and photocatalytic removal of hazardous organic pollutants

Owing to the excellent optoelectronic properties of metal nanoparticle-semiconductor interfaces; hybrid substrates with superior catalytic and sensing properties can be designed. In the present study, we have attempted to evaluate anisotropic silver nanoprisms (SNP) functionalized titanium dioxide (TiO₂) particles for multifunctional applications such as SERS sensing and photocatalytic decomposition of hazardous organic pollutants. Hierarchical TiO₂/SNP hybrid arrays have been fabricated via facile and low-cost casting techniques. The structural, compositional, and optical characteristics of TiO₂/SNP hybrid arrays were well elucidated and correlated to SERS activities. SERS studies revealed that TiO₂/SNP nanoarrays possess almost 288 times enhancement compared to bare TiO₂ substrates and 2.6 times enhancement than pristine SNP. The fabricated nanoarrays demonstrated detection limits down to 10^-12 M concentration levels and lower spot-to-spot variability of ∼ 11%. The photocatalytic studies showed that almost 94 and 86% of rhodamine B and methylene blue were decomposed within 90 min of visible light exposure. Besides, two times enhancement in photocatalytic activities of TiO₂/SNP hybrid substrates was also observed than bare TiO₂. The highest photocatalytic activity was exhibited by SNP to TiO₂ molar ratio of 1.5 × 10^-3. The electrochemical surface area and the interfacial electron-transfer resistance were increased with the increment in TiO₂/SNP composite load from 3 to 7 wt%. Differential Pulse Voltammetry (DPV) analysis revealed a higher RhB degradation potential of TiO₂/SNP arrays than SNP or TiO₂. The synthesized hybrids exhibited excellent reusability without any significant deterioration in photocatalytic properties over five successive cycles. TiO₂/SNP hybrid arrays were proved to be multiple platforms for sensing and degrading hazardous pollutants for environmental applications.

Gamma Radiation Synthesis of Ag/P25 Nanocomposites for Efficient Photocatalytic Degradation of Organic Contaminant

Titanium dioxide (TiO₂) has garnered significant attention among various photocatalysts, whereas its photocatalytic activity is limited by its wide bandgap and inefficient charge separation, making the exploration of new strategies to improve its photocatalytic performance increasingly important. Here, we report the synthesis of Ag/P25 nanocomposites through a one-step gamma-ray radiation method using AgNO₃ and commercial TiO₂ (Degussa P25). The resulting products were characterized by powder X-ray diffraction, UV-Vis diffused reflectance spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The effect of free radical scavengers, feed ratios of Ag/P25, and dose rates on the photocatalytic activity of the Ag/P25 nanocomposites were systematically investigated using rhodamine B under Xenon light irradiation. The results showed that the Ag/P25 photocatalyst synthesized with a feed ratio of 2.5 wt% and isopropyl alcohol as the free radical scavenger at a dose rate of 130 Gy/min exhibited outstanding photocatalytic activity, with a reaction rate constant of 0.0674 min^-1, much higher than that of P25. Additionally, we found that the particle size of Ag could be effectively controlled by changing the dose rate, and the Ag/P25 nanocomposites doped with smaller size of Ag nanoparticles performed higher photocatalytic activities. The synthesis strategy presented in this study offers new insight into the future development of highly efficient photocatalysts using radiation techniques.

Effective Removal of Methylene Blue by Mn3O4/NiO Nanocomposite under Visible Light

Wastewater treatment is indispensable as wastewater can lead to adverse health effects and deteriorate the quality of life on earth. Photocatalysis is a facile methodology to address this issue. In this study, nanocomposites (NCs) of manganese oxide (Mn3O4) and nickel oxide (NiO) were synthesized in different weight ratios via the solid-state reaction route. Structural properties, optical properties, surface morphology, and functional group analysis of the synthesized nanomaterials were conducted using X-ray diffraction (XRD), UV– Vis spectroscopy, scanning electron microscopy (SEM) along with energy-dispersive X-ray (EDX) analysis, and Fourier-transform infrared (FTIR) spectroscopy, respectively. The bandgap of the nanocomposite decreases significantly from 2.35 eV for the Mn3O4 NPs to 1.65 eV for the Mn3O4/NiO nanocomposite (NC). Moreover, adsorption studies followed by the photocatalytic performance of the Mn3O4/NiO NCs were evaluated to determine the removal of methylene blue (MB) dye from wastewater. The photocatalytic performance of the nanocomposite enhances as the ratio of Mn3O4 in the composite increases from one weight percentage to three weight percentage. The photocatalytic degradation efficiency was calculated to be 95%. The results show that the synthesized NCs could play an important role in photocatalytic wastewater purification and environmental remediation.

Removing methylene blue from water: A study of sorption effectiveness onto nanoparticles-doped activated carbon

In this present study, silver (Ag) and titanium dioxide (TiO₂) nanoparticles were successfully deposited on coconut shell-derived activated carbon (CSAC), to synthesize a novel nanocomposite (CSAC@AgNPs@TiO₂NPs) for the adsorption of Methylene Blue (MB) dye from aqueous solution. The fabricated CSAC@AgNPs@TiO₂NPs nanocomposite was analyzed by Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscope (TEM) equipped with Energy Dispersive X-ray spectroscopy (EDS) detector, X-ray Photoelectron Spectroscope (XPS), and Brunauer-Emmett-Teller (BET). The successful deposition of AgNPs and TiO₂NPs on CSAC surface was revealed by the TEM/EDX, SEM, and XPS analysis. The mesopore structure of CSAC@AgNPs@TiO₂NPs has a BET surface area of 301 m²/g. The batch adsorption studies were conducted and the influence of different parameters, i.e., adsorbent dose, adsorption time, initial dye concentration, pH and temperature were investigated. The nonlinear isotherm and kinetic modelling demonstrated that adsorption data were best fitted by Sips isotherm and pseudo-second-order models, respectively. The maximum adsorption capacity of MB onto CSAC@AgNPs@TiO₂NPs by the Sips model was 184 mg/g. Thermodynamic results revealed that the adsorption was endothermic, spontaneous and physical in nature. CSAC@AgNPs@TiO₂NPs revealed that MB absorption by CSAC@AgNPs@TiO₂NPs was spontaneous and endothermic. The uptake capacity of MB was influenced significantly by the presence of competing ions including, NO₃^-, HCO_3, Ca²⁺, and Na⁺. Repeated tests indicated that the CSAC@AgNPs@TiO₂NPs can be regenerated and reused six times before being discarded. The primary separation mechanism between MB dye and CSAC@AgNPs@TiO₂NPs was the electrostatic interaction. Thus, CSAC@AgNPs@TiO₂NPs was an outstanding material, which displayed good applicability in real water with ≥ 97% removal of MB dye.

Enhancing the anti-ageing, antimicrobial activity and mechanical properties of surface-coated paper by Ag@TiO2-modified nanopigments

In this work, the effect of using Ag-doped TiO₂ nanopigments on optical, mechanical and antimicrobial properties of coated paper was explored. Furthermore, the long-term antimicrobial activity of the coated paper was examined for up to 25 years. Titanium dioxide (TiO₂) nanoparticles have been synthesized and doped with different percentages of Ag nanoparticles (Ag NPs) using a simple wet chemical approach. The Ag@TiO₂ modified nanopigments were in the form of nanorods with an average size of about 20 nm as observed from TEM images. Increasing Ag content from 0.01 to 1.0% showed an increase in the mechanical properties of coated paper in terms of tensile, stretching, tensile energy absorption and burst while preserving the optical properties. Moreover, the antimicrobial inhibition activity increased with increasing the Ag content. The 1% Ag@TiO₂ showed a long-lasting antimicrobial effect against Staphylococcus aureus (S. aureus) Gram-positive bacteria even after 25 years of ageing (93.4% inhibition). Investigation of reactive oxygen species (ROS) generation and reaction mechanism of antimicrobial activity over Ag/TiO₂ under visible light is proposed. These results suggest that Ag/TiO₂ NPs can be potentially used as a disinfection coating for paper and improving its mechanical properties.

Silver@mesoporous Anatase TiO2 Core-Shell Nanoparticles and Their Application in Photocatalysis and SERS Sensing

Nanostructured noble metal-semiconductor materials have been attracting increasing attention because of their broad application in the field of environmental remediation, sensing and photocatalysis. In this study, a facile approach for fabricating silver@mesoporousanataseTiO2 (Ag@mTiO2) core-shell nanoparticles employing sol-gel and hydrothermal reaction is demonstrated. The Ag@mTiO2nanoparticles display excellent surface-enhanced Raman scattering (SERS) sensitivity and they can detect the methylene blue (MB) molecules with the concentration of as low as 10−8 M. They also exhibit outstanding photocatalytic activity compared with mTiO2, due to the efficient separation and recombination restrain of electron–hole pairs under ultraviolet light. The Ag@mTiO2nanoparticles also present good stability and they can achieve recyclable photocatalytic degradation experiments for five times without loss of activity. Subsequently, the nanoparticles with dual functions were successfully used to in situ monitor the photodegradation process of MB aqueous solution. These results, demonstrating the multifunctional Ag@mTiO2 nanoparticles, hold promising applications for simultaneous SERS analysis and the removal of dye pollutants in environmental field.

Improving SERS Sensing Efficiency and Catalytic Reduction Activity in Multifunctional Ternary Ag-TiO2-GO Nanostructures: Roles of Electron Transfer Process on Performance Enhancement

Multifunctional nanocomposites have received great attention for years; electron transfer (ET) is considered as an explanatory mechanism for enhancement of performance of these nanostructures. The existence of this ET process has been proved in many studies using either experimental or computational approaches. In this study, a ternary nanocomposite system of Ag/TiO2/GO was prepared to evaluate the performance enhancement in two experimental models: a physical model (i.e., surface-enhanced Raman scattering (SERS) sensor) and a chemical one (i.e., catalytic reduction reaction). The metal/semiconductor heterojunction between Ag and TiO2, as well as Ti-O-C bonds, has allowed plasmonic hot electrons to be transferred in the internal structure of the material. An investigation on the role of Ag content on the SERS sensing and catalytic reduction efficiency of Ag/TiO2/GO was performed in both models. Interestingly, they all resulted in the same optimal Ag content of 50 wt%. It was then further discussed to provide a convincing evidence for the plasmon-induced electron transfer phenomena in the Ag/TiO2/GO nanostructure. These findings also suggest a pathway to design and develop high-performance, cost-effective, facile-preparation, and eco-friendly multifunctional nanostructures for detecting and removing contaminants in environment.

Tailoring the bandgap of Mn3O4 for visible light driven photocatalysis

The photocatalytic activity of pure Mn₃O₄ and silver (Ag) modified Mn₃O₄ nanoparticles have been investigated. The nanoparticles were prepared by using co-precipitation technique. The structural analysis showed that the Ag modified Mn₃O₄ was successfully synthesized. For instance, a slight shift to lower angle of XRD pattern was observed after Ag doping. Morphological analysis revealed that the particles have an average size of 274 nm, 287 nm and 321 nm for pure, 1% and 3% Ag modified Mn₃O₄ respectively. The UV-Visible analysis indicated that the bandgap of Mn₃O₄ decreased with increased Ag content and the band gap is 1.4 eV with the 3% of Ag content. The spectra obtained from DRS were also evaluated through inverse logarithmic derivative method (ILD) to counter check the bandgap values. 3% Ag-modified photocatalysts exhibited the enhanced decolorization efficiency compared to pure Mn₃O₄ nanoparticles. The pseudo first order kinetic model is used to explain the photocatalytic kinetics of the photocatalyst. The rate constant values are 0.01/min, 0.017/min and 0.024/min for pure Mn₃O₄, 1% Ag and 3% Ag modified Mn₃O₄ nanoparticles, respectively.

Synthesis and Characterization of Various Doped TiO2 Nanocrystals for Dye-Sensitized Solar Cells

Few works are reported on solvothermal preparation of nanoparticles by utilizing acetone alone without a surfactant. This synthesis approach is found to be prominent for producing the mesoporous structure, which is crucial in improving the dye loading of the photoanode. In addition, doping of metal ions is advantageous in order to bring down the excitation energy, which is promising for boosting the performance of the doped oxides. This research aims to synthesize various kinds of doped-TiO2 nanocrystals to serve as photoanode materials in dye-sensitized solar cells (DSSCs). An X-ray diffraction study evidenced the existence of the crystalline phase in pure and doped-TiO2 nanocrystals. Rietveld refinement study showed the mixed phases of crystalline TiO2 in the CrT, CuNT, and ST as compared to a single anatase phase in the samples PT, AgT, BT, CoT, FeT, SnT, ZT, VT, and ZMT. The absorption spectroscopy analysis demonstrated the reduced optical band gap from 3.10 to 2.79 eV. Scanning electron microscopy investigation endorsed the formation of TiO2 mesoporous microspheres with a mean diameter ranging from 200 to 331 nm along with a nanocrystal diameter ranging from 10 to 20 nm. Doping with the different dopants enhanced the conversion efficiency of DSSCs from 1.31 to ∼6%. Furthermore, we have performed the electrochemical impedance spectroscopy of DSSCs, and the findings are presented.

Photocatalytic Activity of Silver-Based Biomimetics Composites

Different Ag@TiO2 and Ag@ZnO catalysts, with nanowire (NW) structure, were synthesized containing different amounts of silver loading (1, 3, 5, and 10 wt.%) and characterized by FE-SEM, HRTEM, BET, XRD, Raman, XPS, and UV-vis. The photocatalytic activity of the composites was studied by the production of hydrogen via water splitting under UV-vis light and the degradation of the antibiotic ciprofloxacin. The maximum hydrogen production of all the silver-based catalysts was obtained with a silver loading of 10 wt.% under irradiation at 500 nm. Moreover, 10%Ag@TiO2 NWs was the catalyst with the highest activity in the hydrogen production reaction (1119 µmol/hg), being 18 times greater than the amount obtained with the pristine TiO2 NW catalyst. The most dramatic difference in hydrogen production was obtained with 10%Ag@TiO2-P25, 635 µmol/hg, being 36 times greater than the amount reported for the unmodified TiO2-P25 (18 µmol/hg). The enhancement of the catalytic activity is attributed to a synergism between the silver nanoparticles incorporated and the high surface area of the composites. In the case of the degradation of ciprofloxacin, all the silver-based catalysts degraded more than 70% of the antibiotic in 60 min. The catalyst that exhibited the best result was 3%Ag@ZnO commercial, with 99.72% of degradation. The control experiments and stability tests showed that photocatalysis was the route of degradation and the selected silver-based catalysts were stable after seven cycles, with less than 1% loss of efficiency per cycle. These results suggest that the catalysts could be employed in additional cycles without the need to be resynthesized, thus reducing remediation costs.

Synthesis of Mn-doped and anatase/rutile mixed-phase TiO2 nanofibers for high photoactivity performance

A soft membrane of Mn@TiO₂ NFs was fabricated by an electrospinning and thermal annealing process. It shows a mixture phase and a palpably increased specific surface area, which ensured a pronounced enhancement of the photocatalytic activity.

Highly stable AgNPs prepared via a novel green approach for catalytic and photocatalytic removal of biological and non-biological pollutants

Increases in biological and non-biological pollutants pose a significant threat to environmental systems. In an effort to develop an effective means to treat such pollutants, the use of Phaseolus vulgaris (kidney beans) as reducing and capping agents is proposed for the green synthesis of highly stable silver nanoparticles (AgNPs) with a face-centered cubic (fcc) crystalline structure (size range: 10-20 nm). The potent role of the resulting AgNPs was found as triple platforms (photocatalyst, catalyst, and antimicrobial disinfectant). AgNPs were able to photocatalytically degrade approximately 97% of reactive red-141 (RR-141) dye within 150 min of exposure (quantum efficiency of 3.68 × 10^-6 molecule.photon^-1 and a removal reaction kinetic rate of 1.13 × 10^-2 mmol g^-1 h^-1). The role of specific reactive oxygen species (ROS) in the photocatalytic process and complete mineralization of dye was also explored through scavenger and chemical oxygen demand (COD) experiments, respectively. As an catalyst, AgNPs were also capable of reducing 4-nitrophenol to 4-aminophenol within 15 min. Overall, AgNPs showed excellent stability as catalyst and photocatalyst even after five test cycles. As an antimicrobial agent, the AgNPs are effective against both gram-positive (Bacillus subtilis) and -negative bacteria (Escherichia coli), with the zones of clearance as 15 and 18 mm, respectively. Thus, the results of this study validate the triple role of AgNPs derived via green synthesis as a photocatalyst, catalyst, and antimicrobial agent for effective environmental remediation.

Gram-scale synthesis of splat-shaped Ag-TiO2 nanocomposites for enhanced antimicrobial properties

The control over contagious diseases caused by pathogenic organisms has become a serious health issue. The extensive usage of antibiotics has led to the development of multidrug-resistant bacterial strains. In this regard, metal-oxide-based antibacterial nanomaterials have received potential research interest due to the efficient prevention of microorganism growth. In this study, splat-shaped Ag-TiO₂ nanocomposites (NCs) were synthesized on the gram scale and the enhanced antibacterial properties of TiO₂ in the presence of silver were examined. The formation of Ag-TiO₂ NCs was analyzed through various characterization techniques. The cell viability experimental results demonstrated that the Ag-TiO₂ NCs have good biocompatibility. The antibacterial activity of the prepared Ag-TiO₂ NCs was tested against the Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacterial strains. The Ag-TiO₂ NCs exhibited promising and superior antibacterial properties compared to TiO₂ nanospheres as confirmed by the bacterial growth and inhibition zone. The improvement in the antibacterial activity was attributed to the synergistic effect of the hybrid nature of TiO₂ nanoparticles in the presence of Ag.

Galvanic Replacement-Enabled Synthesis of In(OH)3/Ag/C Nanocomposite as an Effective Photocatalyst for Ultraviolet C Degradation of Methylene Blue

Sub-10 nm indium metal nanoparticles (In NPs) stabilized on conductive carbon were reacted with silver nitrate in dark conditions in water at room temperature in a galvanic replacement manner to produce an indium hydroxide/silver/carbon nanocomposite (In(OH)3/Ag/C). The chosen carbon imparted colloidal stability, high surface area, and water dispersibility suitable for photodegradation of harmful dyes in water. The size and shape of indium hydroxide and silver nanoparticles produced were found to be 6.6 ± 0.9 nm, similar to that of the In NPs that were started with. The nanocomposite was characterized by transmission electron microscopy, energy dispersive X-ray spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. The galvanic reaction between In NPs and silver nitrate was tracked with UV-vis spectroscopy in a control experiment without a carbon substrate to confirm that the reaction was indeed thermodynamically spontaneous as indicated by the positive electromotive force (EMF) of +1.14 V calculated for In/Ag+ redox couple. The photocatalytic performance of the nanocomposite was evaluated to be approximately 90% under UVC radiation when 10 ppm of methylene blue and 13 wt % of indium hydroxide/silver loading on carbon were used.

Kale M, Divakaran N, Senthil T, P. S, Wu L, Wang J. A Novel Approach to Enhance Mechanical and Thermal Properties of SLA 3D Printed Structure by Incorporation of Metal-Metal Oxide Nanoparticles

Silver (Ag) ornamented TiO₂ semiconducting nanoparticles were synthesized through the sol-gel process to be utilized as nanofillers with photo resin to enhance the mechanical and thermal properties of stereolithography 3D printed objects. The as-prepared Ag-TiO₂ nanoparticles (Ag-TNP) were typified and qualified by XRD, XPS, Raman, and FESEM; TEM analysis dissected the morphologies. The enhancement in the tensile and flexural strengths of SLR/Ag-TNP nanocomposites was noted as 60.8% and 71.8%, respectively, at the loading content of 1.0% w/w Ag-TNP within the SLR (stereolithography resin) matrix. Similarly, the thermal conductivity and thermal stability were observed as higher for SLR/Ag-TNP nanocomposites, equated to neat SLR. The nanoindentation investigation shows an excerpt hike in reduced modulus and hardness by the inclusion of Ag-TNP. The resulted thermal analysis discloses that the introduction of Ag-TNP can appreciably augment the glass transition temperature (T_g), and residual char yield of SLR nanocomposites remarkably. Hence, the significant incorporation of as-prepared Ag-TNP can act as effective nanofillers to enhance the thermal and mechanical properties of photo resin.

Enhanced Photocatalytic Performance and Mechanism of Au@CaTiO3 Composites with Au Nanoparticles Assembled on CaTiO3 Nanocuboids

Using P25 as the titanium source and based on a hydrothermal route, we have synthesized CaTiO₃ nanocuboids (NCs) with the width of 0.3–0.5 μm and length of 0.8–1.1 μm, and systematically investigated their growth process. Au nanoparticles (NPs) of 3–7 nm in size were assembled on the surface of CaTiO₃ NCs via a photocatalytic reduction method to achieve excellent Au@CaTiO₃ composite photocatalysts. Various techniques were used to characterize the as-prepared samples, including X-ray powder diffraction (XRD), scanning/transmission electron microscopy (SEM/TEM), diffuse reflectance spectroscopy (UV-vis DRS), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Rhodamine B (RhB) in aqueous solution was chosen as the model pollutant to assess the photocatalytic performance of the samples separately under simulated-sunlight, ultraviolet (UV) and visible-light irradiation. Under irradiation of all kinds of light sources, the Au@CaTiO₃ composites, particularly the 4.3%Au@CaTiO₃ composite, exhibit greatly enhanced photocatalytic performance when compared with bare CaTiO₃ NCs. The main roles of Au NPs in the enhanced photocatalytic mechanism of the Au@CaTiO₃ composites manifest in the following aspects: (1) Au NPs act as excellent electron sinks to capture the photoexcited electrons in CaTiO₃, thus leading to an efficient separation of photoexcited electron/hole pairs in CaTiO₃; (2) the electromagnetic field caused by localized surface plasmon resonance (LSPR) of Au NPs could facilitate the generation and separation of electron/hole pairs in CaTiO₃; and (3) the LSPR-induced electrons in Au NPs could take part in the photocatalytic reactions.