Composite Nanoparticles Research Articles

(Keynote) Macroscopic Materials Synthesized from Nanoparticle Superlattices

One of the promises of nanotechnology in its early developmental stages was the ability to make designer materials with precise control over individual building block composition and organization in 3D space. In recent years, material synthesis methods have advanced to be able to create a multitude of nanoparticles of varying sizes, shapes, and compositions, providing a vast array of building blocks to use as materials fabrication components. Additionally, processing methods have been developed to arrange these nanoparticles into ordered arrays, to dry them into thin films, and even to sinter them into more complex bulk solids. However, the fundamental promise of being able to build a material with controlled hierarchical structure across all length scales (atomic crystal structure, molecular composition; nanoscale feature size, shape, and organization; microstructure; macroscopic form) has been challenging to realize. A materials synthesis and processing route that could create free-standing, macroscopic materials or arbitrary three-dimensional shapes with precisely controlled nanoparticle positions across the entirety of the material composition would therefore be a major advancement. Here, we demonstrate a nanoparticle-based building block called a “Nanocomposite Tecton (NCT)” that enables a self-assembly route to fabricating free-standing 3D solids of arbitrary macroscopic shapes that can utilize a multitude of different nanoparticle compositions, and also possess specifically programmed nanoscale particle arrangements and controlled microstructure. This talk will outline the key synthesis and processing steps that enable this method of making materials with programmed material structure across ~7 orders of magnitude in length scale, thereby realizing a long-standing goal of nanomaterials fabrication.

Nanoparticles for Active and Sustainable Fuel Cell Cathodes

Depletion of fossil fuels and environmental pollution raised interest in new technologies for sustainable energy production, conversion, and storage, among which fuel cell technology is greatly studied, in both academia and industry. Proton exchange membrane fuel cells (PEMFCs) are reputed energy devices, due to their high conversion efficiency and low environmental pollution.1 Nowadays, Pt-based catalysts exhibit the best electrocatalytic activity towards oxygen reduction reaction (ORR), but enhancing their catalytic efficiency and reducing costs are essential for commercializing fuel cell technology.2 Our interest relies with the development of Pt-based nanoalloys2,4 via solution organometallic chemistry approach.3 This approach allows control over the composition, structure, and morphology of metal nanoparticles, and could lead to increased catalytic activity and long-term stability by revealing more active sites of the catalyst. Additionally, the ability to alloy with a range of metals for producing bimetallic compounds is one of the key advantages of this approach.In this communication, the synthesis of Pt-based nanoparticles and their characterization by state-of-the-art techniques such as ICP, EA, IR, TEM and HR-TEM will be described. The influence of the Pt complexes used as precursors and of the reaction conditions on the morphology of the Pt nanoparticles will be shown. The obtained nanostructures offer interesting starting materials to incorporate other metals, such as transition or rare earth metals, in order to have nanoalloys and study their performance in ORR in comparison to pure Pt catalysts.

(Invited) Bragg Coherent Diffraction Imaging Studies of Composition Distribution and Strain in Catalytic Alloy Nanoparticles

Compositional distribution, strain, and defects in alloy nanoparticles significantly affect the catalytic properties for a wide range of applications such as gas reforming, fuel cells, electrolysis, etc. while various alloy compositions of nanoparticles have been investigated to improve performance and reduce the amount of precious metals used. It was reported that the composition distribution of the alloy particles, expectedly homogeneous in the whole particle, changed dynamically depending on the operating environment, resulting in altering the catalytic activity [1]. Furthermore, defects such as dislocations, grain boundaries, and elastic strain of the crystalline lattice also significantly affect catalytic properties. Since these factors dynamically change and evolve under operating environments, in situ measurements are essential to reveal these factors and ultimately to exploit them to enhance the catalytic properties. Bragg coherent diffraction imaging (BCDI) is a lens-less imaging method that measures speckle patterns near Bragg diffraction from a crystalline sample and reconstructs the 3D particle images. Since Bragg diffraction is inherently sensitive to displacements of the crystal lattice, BCDI yields the displacement field within the sample as well as the electron density, i.e., the “shape” of the particle. This displacement field information further allows us to evaluate strain distribution, dislocations, and composition distribution in the particle. BCDI is also advantageous for in situ measurements because the 3D image can be obtained by rotating the sample by only a few degrees, which eases the geometrical constraint of an electrochemical cell for the measurement. This is in contrast to conventional 3D imaging techniques such as X-ray CT, which usually requires 180 degrees of sample rotation.Furthermore, it is expected that the measurement capabilities of BCDI will be rapidly advanced by upgrading synchrotron radiation facilities such as APS-U, which delivers high-flux coherent X-rays. This should expand the applications of BCDI to wider electrochemical materials. In this presentation, we will briefly overview the principle of BCDI followed by specific examples of in situ measurements of catalytic alloy particles [2-4] conducted at 34-ID-C at Advanced Photon Source.[1] F. Tao et al., Science 322, 932 (2008).[2] T. Kawaguchi et al., Phys. Rev. Lett. 123, 246001 (2019).[3] T. Kawaguchi et al., Nano Lett. 21, 5945 (2021).[4] D. Sheyfer, R. G. Mariano, T. Kawaguchi, et al., Nano Lett. 23, 1 (2023).

Chemical Composition of Anabasis articulata, and Biological Activity of Greenly Synthesized Zinc Oxide Composite Nanoparticles (Zn-NPs): Antioxidant, Anticancer, and Larvicidal Activities

The synthesis of nanoparticles utilizing green techniques is becoming increasingly important due to its low cost, biocompatibility, high productivity, and eco-friendliness. Herein, the current work focused on the biosynthesis, characterization, and biological applications of zinc oxide nanoparticles (ZnO-NPs) from Anabasis articulata, including antioxidant anticancer and larvicidal properties, as well as modifications to the phytochemical ingredients. Hence, the tannin, phenolic, and flavonoid concentrations of the produced nanoparticle samples were lower than those of the original aqueous extract. When compared to the results of ascorbic acid (12.78 mg/mL), the produced extract of A. articulata and its zinc nanoparticles showed remarkable efficacy as antioxidant agents with IC50 values of 27.48 and 69.53 mg/mL, respectively. A normal lung fibroblast cell line (WI-38) and three tumor cells were used to test the compounds’ anticancer properties. With an IC50 of 21.19 µg/mL, the ZnO-NPs of A. articulata showed the greatest cytotoxicity against HePG-2 cell lines. Additionally, A. articulata zinc nanoparticles showed significant cytotoxicity against MCF-7 and PC3 tumor cell lines, with IC50 values of 30.91 and 49.32 µg/mL. The biogenic ZnO-NPs had LC50 and LC90 values of 13.64 and 26.23 mg/L, respectively, and are very effective against Aedes aegypti larval instar (III). Additionally, the percentages of larval mortality increased from 28.61% at 5 ppm to 84.69% at 25 ppm after 24 h post-treatment. The overall results of this study point to the potential of A. articulata as a substitute biological agent for potential therapeutic/leutic uses in the medical domains and for preventing the proliferation of malarial vector insects.

Interaction of zein/HP-β-CD nanoparticles with digestive enzymes: Enhancing curcumin bioavailability

The low bioavailability of polyphenolic compounds due to poor solubility and stability is a major challenge. Encapsulation of polyphenols in zein-based composite nanoparticles can improve the water dispersion, stability, targeted delivery, and controlled release of polyphenols in the gastrointestinal tract. In this study, we investigated the fluorescence properties, bioactivity, and microstructural characteristics of polyphenols during digestion, revealing that zein nanoparticles protect polyphenols from gastric degradation and promote their sustained release in the small intestine. The effects of different ionic species and salt ion concentrations on the digestive properties of polyphenol complex delivery systems have also been explored. In addition, the formation of “protein corona” structures during digestion may affect bioavailability. These findings highlight the potential of nanoparticle formulations to improve polyphenol stability and absorption. The results of this study may provide new insights and references for the study of polyphenol bioavailability enhancement.

Development of an Effective Au : Pd Bimetallic Heterogeneous Catalyst for Oxidative Lignin Depolymerization to Low Molecular Weight Aromatics

AbstractLignin, a phenolic‐rich biomass component, holds promise for producing value‐added products. However, its complex structure and recalcitrance present challenges for its effective utilization. To overcome this, a AuPd/Li−Al layered double hydroxide (LDH) catalyst was developed to facilitate lignin depolymerization. Various AuPd bimetallic nanoparticle compositions were supported on a basic Li−Al LDH support via a sol‐immobilization method and characterized using N2‐physisorption, X‐ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The catalysts were then evaluated in the oxidation of several benzylic alcohols using O2 as the oxidant, from which Au7Pd3/Li−Al LDH and Au1Pd1/Li−Al LDH were identified as possessing promising catalytic activity. Further investigations focused on the aerobic oxidation of β‐O‐4 linked lignin model dimers under atmospheric pressure. The tested catalysts demonstrated sequential oxidation of the model compounds, leading to cleavage of the β‐O‐4 linkage. Finally, the catalysts were applied to the oxidative deconstruction of γ‐valerolactone (GVL) extracted maple lignin at 120 °C. Au1Pd1/Li−Al LDH emerged as the most effective catalyst, yielding a range of aromatic monomers with a total monomer yield of 27 %. These results highlight the potential of the Au1Pd1/Li−Al LDH catalyst system as an eco‐friendly approach for lignin depolymerization under mild conditions.

Aminated nano-crystalline cellulose decorated binary Ag-ZnO nanocomposite particles with a comparative study of antimicrobial activity and cell viability

In this research, the objective is to prepare cytotoxically less active biocompatible aminated nanocrystalline cellulose (NCC) decorated Ag-ZnO nanocomposite particles. For this, raw rice (Oryza sativa) straw is employed as a primary source of cellulose. The raw rice straw collected from local agricultural field is first exposed to alkali treatment and subsequent bleaching to remove non-cellulosic components. Acid hydrolysis with 60 % (v/v) H2SO4 produced tiny spherical (147 nm) as well as few needle-shape (96 nm) particles with the highest crystalline index (77 %). The ultra-small particles, termed as nanocrystalline cellulose (NCC), are amine functionalized before decorating binary Ag-ZnO nanoparticles (NPs) following an in-situ green co-reduction protocol. The crystallinity and valence states of Ag-ZnO NPs in the nanocomposite, named as NCCNH2@Ag-ZnO, are well maintained. A comparative study of antimicrobial activity and cell viability (against brine shrimp eggs i.e., Artemia salina) among Ag-ZnO NPs, NCC@Ag-ZnO and NCCNH2@Ag-ZnO nanocomposites is carried out. Due to the presence of multiple coordination sites on NCCNH2, the stable network of NCCNH2@Ag-ZnO nanocomposite particles showed the minimum antimicrobial activity and cytotoxicity. Hence, the NCCNH2@Ag-ZnO nanocomposite would be relatively safe for use in wound healing/dressing materials, disinfectants and food packaging.

Efficacy of mesoporous TiO2–ZrO2@g-C3N4 produced using a simple ultrasonic approach for copper ion removal from wastewater

The present study describes ultrasonically produced ternary composite material composed of carbon nitride nanosheets, zirconium, and titanium oxides for elimination of copper ions. The formation of monoclinic ZrO2, anatase TiO2, and g-C3N4 phases with respective crystallite sizes 6, 11, 13 nm were verified by the X-ray diffraction technique. The dispersion of the metal oxides nanoparticles with the graphitic nanosheets, the elemental composition of Zr, Ti, O, C and N, and the characteristic functional groups were verified respectively by TEM, EDX, and FTIR analysis that confirmed the successful formation and composition of the nanocomposite TiO2–ZrO2@g-C3N4 (TZCN). The good porosity of the composite that show a surface area, pore volume, and pore diameter values of 47.42 m2/g, 0.056 cm3 g−1, and 20.3 Å that nominate it for adsorption application. The adsorption capabilities of the nanocomposite were studied for copper ion removal from an aqueous solution, as well as the impacts of pH and starting Cu2+ concentration. The results show that the adsorption process is pH and starting concentration-dependent, with a maximum adsorption capacity of 447.8 mg/g. The Cu2+ adsorption is a monolayer chemisorption process that is well described by the Langmuir adsorption model and follows pseudo-second-order kinetics. Moreover, a plausible mechanism for Cu2+ ion adsorption on the surface of TZCN nanocomposite particles is proposed.

Fabrication, characterization, and dihydromyricetin-loaded bioavailability of Pickering emulsions stabilized by Ampelopsis grossedentata polysaccharide -fish collagen peptide composite nanoparticles

A novel strategy was devised to synthesize robust nanocarriers by conjugating fish collagen peptides (FCP) with Ampelopsis grossedentata polysaccharide (AGP), culminating in the creation of FCP-AGP nanoparticles (FCAGPs) for advanced drug delivery systems. The innovative approach entailed the systematic investigation of particle size, zeta potential, and surface hydrophobicity alterations in FCAGPs upon varying AGP concentrations. The optimized FCAGP-4 nanoparticles, boasting a precisely engineered AGP content of 2.0 % (w/v) and an average particle diameter finely tuned to 353.2 ± 10.5 nm, demonstrated outstanding characteristics in dispersibility, stability, and emulsifying capacity. Furthermore, the water contact angle of FCAGP nanoparticles notably increased from 46.3 ± 2.8° to 70.2 ± 5.6°, indicating enhanced surface hydrophobicity. The mechanism by which FCAGP nanoparticles were attached to the surface of oil droplets to stabilize the emulsions was elucidated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Significantly, a modified sample pretreatment technique was employed to demonstrate clearly the emulsion phase interface on the SEM.Innovative FCAGP-stabilized Pickering emulsions achieved 65.39 % in DMY bioavailability, facilitating its slow-release and enhanced bioaccessibility during in vitro digestion. Pickering emulsions loaded DMY demonstrated improved stability and sustained release under simulated digestive conditions, bolstering its therapeutic efficacy. Our findings solidify the theoretical basis for green synthesis of propeptide-polysaccharide nanoparticles and introduce a novel strategy for targeted propeptide Pickering emulsions in drug delivery, highlighting the transformative potential of FCAGP nanoparticles in enhancing lipophilic drug bioavailability and pharmacological impact.

A novel pharmacological strategy using nanoparticles with glutathione and virgin coconut oil to treat gentamicin-induced acute renal failure in rats.

In acute renal failure (ARF), the glomerular filtration rate is reduced, and nitrogenous waste products accumulate persistently, which can last anywhere from a few hours to several days. There is hope for a reversal of the rapid loss of renal function caused by this condition. This study, with gentamicin-induced acute ARF as a prospective setting, sets out to examine the reno-protective benefits of virgin coconut oil (VCO) and GSH. Furthermore, the study evaluated the effect of medication nanoparticle compositions on several kidney function markers. The induction of ARF is achieved with the intraperitoneal injection of gentamicin. To assess renal function, rats underwent 24h of dehydration and hunger before their deaths. The study examined various aspects, including kidney function tests, markers of oxidative stress, histology of kidney tissue, inflammatory cytokines, immunohistochemistry expression of nuclear factor-kappa B (NF-κB), and specific biomarkers for kidney tissue damage, such as kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL). The results of our study indicated that the combination of VCO and GSH, using both regular and nanoparticle formulations, had a better protective impact on the kidneys compared to using either drug alone. The recovery of renal tissue and serum markers, which are symptomatic of organ damage, indicates improvement. This was also demonstrated by the reduction in tubular expression of TNF-α, IL-1β, KIM-1, and NGAL. The immunohistochemical studies showed that the combination therapy, especially with the nanoforms, greatly improved the damaged cellular changes in the kidneys, as shown by higher levels of NF-κB. The study shows that VCO and GSH, when administered individually or combined, significantly improve ARF in a gentamicin-induced rat model, highlighting potential therapeutic implications. Notably, the combined nanoparticulate formulations exhibit substantial effectiveness.

Study on carbon allotrope abrasive particles based on C60 molecule for diamond chemical mechanical polishing

In this study, we developed C60 reactive diamond composite particles for the chemical mechanical polishing (CMP) of diamond substrates by applying the high hardness and high reactivity of the C60 molecule. When diamond substrates were polished using these C60 diamond composite particles, the polished surface was found to be superior to that of diamond particles. In addition, when the composite particles were irradiated with ultraviolet light to produce polishing fine particles, the polishing rate was improved by about 30%. These results indicate that the composite nanoparticles that reacted with C60 have the potential to remove even the hardest of diamond substrates.

Synthesis and characterization of oleic acid-stabilized cobalt ferrite @MCM-41/nanocomposites for pH-responsive drug delivery

This study presents composite nanoparticles combining cobalt ferrites-oleic acid (CF-OA) and mesoporous silica (MCM-41) for drug delivery. Temperature-dependent analyses at 25 and 42 °C reveal distinct alterations in particle size and distribution, emphasizing the role of oleate complexes in stabilizing the nanocomposites. Power of Laws calculations (n = 0.58, m = 0.44) assessed diffusion and matrix erosion effects, highlighting the pH-responsive behavior. Results showed CF-OA@MCM-41with nanometric scale and predominantly spherical morphology influenced by temperature variations. Nitrogen BET analysis revealed a surface area of 542.1 m2g−1 and a pore volume of 1.1 cm3g−1. Drug release studies demonstrated controlled doxorubicin (DOX) release from CF-OA@MCM-41. In vivo studies showed significant tumor growth suppression (liver cancer): average tumor volume in D-C@M group was 167.8 mm3 after 21 days, compared to 1953.8 mm3, 1203.6 mm3, and 269 mm3 for PBS, CF-OA@MCM-41, and DOX alone respectively. In vitro, a 3 µg mL−1 concentration showed no significant 293 T cell viability change and increased HEP G2 cell viability. Significant HEP G2 cell viability inhibition occurred at 1 and 2 µg mL−1 CF-OA@MCM-41 carrying DOX, with p-values < 0.01 and < 0.001. CF-OA@MCM-41 nanoparticles exhibit promising potential for targeted cancer therapy due to their pH sensitivity and controlled drug release capabilities.

Erythrocyte membrane-camouflaged mesoporous silica composite nanoparticles for loading and controlled release of the hepatoprotective agent silibinin: A-synthesis and physicochemical characterization.

Milk thistle has long been used in the treatment of liver and biliary disorders. In the present study, to make a long-acting delivery system for silibinin (SBN, a major active constituent of milk thistle seeds with antioxidant and hepatoprotective function), mesoporous silica composite nanoparticles (NC) were synthesized and coated with RBC membrane. A modified Stöber method was used for NC synthesis, which was then characterized using FE-SEM, DLS, TEM, FTIR, and EDAX techniques. A suitable lysis buffer was used to prepare RBC-ghost, and sonication was used to coat SBN-loaded NC (SBN-NC). The RBC-ghost coated SBN-NC (SBN-NC-RBCG) was evaluated by SDS-PAGE, Bradford, TEM, EDAX, and DLS methods. SBN release was then compared for the SBN-NC and SBN-NC-RBCG samples. the RBC membrane proteins were recovered from the coating of SBN-NC-RBCG, and SBN release was sustained over 24 h when compared with the SBN-NC. Overall, through prolonging circulation in the bloodstream and evading the immune system, the developed system can improve SBN bioavailability in liver inflammation and fibrosis conditions that need further research.

True-solution-scale utilization of natural chlorophyll a in aqueous media through cooperative aggregation with phycocyanin

The challenge of applying chlorophyll(Chl) in aqueous media has been a significant obstacle to the diversified development of Chl a-related industries. This study presents the first report on the true-solution-scale utilization of Chl in aqueous media through the construction of chlorophyll a-phycocyanin (Chls-PC) composite nanoparticles. This study determined the optimal conditions for Chls-PC preparation: a composite ratio of 1:25, a solvent ratio of 1:4, and a stirring time of 1 h. Fluorescence spectroscopy, transmission electron microscope, and confocal microscopy confirmed Chl a and PC aggregation. Surface hydrophobicity and contact angle measurements showed that Chls-PC water solubility was similar to PC and much higher than Chl. Infrared spectroscopy, quantum chemical calculations, X-ray photoelectron spectroscopy, and molecular dynamics simulations elucidated the water solubilization mechanism of Chls-PC both experimentally and theoretically. This research provides theoretical guidance for the development and production of water-based products using Chl as a raw material.

Unveiling the effect of Bi in ZnFe2O4 nanoparticles in electrochemical sensors

This work investigates the effect of the inclusion of Bi3+ ions in ZnFe2O4 nanoparticles on electron transfer at the electrochemical interface. ZnBixFe2-xO4 (x = 0, 0.5, 1, 2) nanomaterials are synthesized and the impact of Bi3+ ions on the chemical features of ZnFe2O4 nanoparticles is studied by using different materials’ characterization techniques. The effect of the change in the chemical composition of ZnFe2O4 nanoparticles on the electrochemical sensing performance is extensively studied and correlated with the electrochemical sensitivity and kinetic rate constant. Screen-printed electrodes functionalized with ZnBixFe2-xO4 nanomaterials have an excellent enhancement of electrochemical sensing performance towards paracetamol, as a test molecule, compared to the carbon electrodes. The highest sensitivity (37.8 ± 0.2 μA/mM) and the best kinetic rate constant (13.1 ± 2.8 ms−1) are achieved by the ZnFe2O4 sensor, while the ZnBi2O4 sensor achieved a sensitivity of (23.5 ± 0.6) μA/mM with a kinetic rate constant of (0.45 ± 0.16) ms−1. The ZnFe2O4 sensor is found to have a direct electron transfer, whereas the other sensors participate in a surface state-mediated electron transfer at the electrochemical interface. This research shows a clear path to the potential applications of spinel oxide-based electrochemical sensors for specific drugs or molecules detection.

Research Progress on the Preparation of Manganese Dioxide Nanomaterials and Their Electrochemical Applications.

Manganese dioxide (MnO2) nanomaterials have shown excellent performance in catalytic degradation and other fields because of their low density and great specific surface area, as well as their tunable chemical characteristics. However, the methods used to synthesize MnO2 nanomaterials greatly affect their structures and properties. Therefore, the present work systematically illustrates common synthetic routes and their advantages and disadvantages, as well as examining research progress relating to electrochemical applications. In contrast to previous reviews, this review summarizes approaches for preparing MnO2 nanoparticles and describes their respective merits, demerits, and limitations. The aim is to help readers better select appropriate preparation methods for MnO2 nanomaterials and translate research results into practical applications. Finally, we also point out that despite the significant progress that has been made in the development of MnO2 nanomaterials for electrochemical applications, the related research remains in the early stages, and the focus of future research should be placed on the development of green synthesis methods, as well as the composition and modification of MnO2 nanoparticles with other materials.

Supreme capture of Europium(ΙΙΙ) by silica-hyperbranched poly(ethylene imine) composites from aqueous solutions − A mechanistic study

Two bio-inspired variations of the sol–gel technique produced silica-hyperbranched poly (ethylene imine) (PEI) composite nanoparticles (NP) and xerogels (XG). Both methods are performed in ambient conditions and do not require toxic organic solvents or high temperatures. We have investigated the removal efficiency of trivalent europium by these two hybrid species in near-neutral aqueous solutions. The adsorption kinetics and isotherms, including data fitting with the pseudo-first and second order kinetic, and the Langmuir isotherm model are presented and discussed. Thermodynamic parameters indicate exothermic reaction (–180 kJ/mol for NP and –192 kJ/mol for XG, respectively) In addition, spectroscopic (Fourier Transform Infra-Red FTIR, Fluorescence Spectroscopy FS, X-ray Photoelectron Spectroscopy XPS) and microscopic techniques (Scanning Electron Microscopy SEM coupled with Energy Dispersive X-ray analysis EDX), as well as ζ-potential and Dynamic light scattering (DLS) measurements, have been employed to evaluate the interaction mechanism between the surface active moieties and Eu(III). The extremely high and homogeneous dispersion of the amino and silicate groups of the composites has led to the highest capacity value (22 mmol/g or 3343 mg/g and 14 mol/g or 2128 mg/g for the two distinct forms of the nanoparticles and the xerogels, respectively) reported up to today implying a potential application for lanthanide recovery. The adsorption data along with the spectroscopic and microscopic indicate that the adsorption is well described by the Langmuir isotherm model and is based on the formation of inner- and outer-sphere complexes between Eu(III) the amine and −Si-O− moieties.

Unveiling superior chemical mechanical polishing properties of a novel shell-core structure: Insights from an atomic-scale perspective

The precision polishing process plays a crucial role in the modern advanced semiconductor manufacturing field, making it imperative to develop excellent polishing abrasives through new techniques. In this study, we obtained well-defined spherical nano-composite polishing particles CeO2@SiO2 via posterior grafting synthesis, which have a clear core–shell structure and exhibit a high Ce3+ concentration. Atomic force microscopy revealed significant improvement in surface roughness of the abrasives on Si substrates, achieving the material removal rate (MRR) of 300 nm/min. MRR is closely correlated with the Ce3+ concentration. Combining aberration-corrected transmission electron microscopy with first-principles calculations demonstrated that surface oxygen vacancies and interfacial charge transfer were the primary origins of high Ce3+ concentration, and revealed the material removal mechanism. This work not only provides new insights into the process but also offers new routes for the development of novel polishing abrasives in the future.

Engineering of LiTaO3 Nanoparticles by Flame Spray Pyrolysis: Understanding In Situ Li-Incorporation into the Ta2O5 Lattice.

Lithium tantalate (LiTaO3) perovskite finds wide use in pyroelectric detectors, optical waveguides and piezoelectric transducers, stemming from its good mechanical and chemical stability and optical transparency. Herein, we present a method for synthesis of LiTaO3 nanoparticles using a scalable Flame Spray Pyrolysis (FSP) technology, that allows the formation of LiTaO3 nanomaterials in a single step. Raman, XRD and TEM studies allow for comprehension of the formation mechanism of the LiTaO3 nanophases, with particular emphasis on the penetration of Li atoms into the Ta-oxide lattice. We show that, control of the High-Temperature Particle Residence Time (HTPRT) in the FSP flame, is the key-parameter that allows successful penetration of the -otherwise amorphous- Li phase into the Ta2O5 nanophase. In this way, via control of the HTPRT in the FSP process, we synthesized a series of nanostructured LiTaO3 particles of varying phase composition from {amorphous Li/Ta2O5/LiTaO3} to {pure LiTaO3, 15-25 nm}. Finally, the photophysical activity of the FSP-made LiTaO3 was validated for photocatalytic H2 production from H2O. These data are discussed in conjunction with the role of the phase composition of the LiTaO3 nanoparticles. More generally, the present work allows a better understanding of the mechanism of ABO3 perovskite formation that requires the incorporation of two cations, A and B, into the nanolattice.

Self-assembly TiO2@Silane@SiO2 core-shell as s-scheme heterojunction photocatalyst against methylene blue degradation: synthesis and mechanism insights

Pollutants are the most critical threats to the health of water resources. On this basis, fabricating a core-shell as an S-scheme heterojunction photocatalyst for the treatment of wastewater from methylene blue (MB) dye was aimed in this research. In this study, TiO2-doped silanized silica dielectric nanocomposites were synthesized as self-assembly TiO2@Silane@SiO2 heterojunction through sol-gel and solvothermal methods using tetrabutyl orthotitanate (TBOT) as precursor followed by calcination at 650 °C for 3 h. Silanization of silica nanoparticles was done at two different concentrations. The results showed that layer-by-layer synthesis (i.e. self-assembly of APTES on SiO2, precipitation of TiO2 layer on it by sol-gel technique and then calcination) was the optimum preparation method. The structural and morphological features were investigated by XRD, FTIR, BET, TGA-DTG, FE-SEM, EIS and ESR techniques. It was found that the band gap energy of nanocomposite particles reduced from 3.14 eV for the sample prepared by the solvothermal method (i.e. without APTES) to 2.91 eV (i.e. shifting the light absorption from UV to the visible region) for the sample prepared by the sol-gel layer-by-layer method. The prepared samples were used against the photo-degradation of MB. TiO2@Silane@SiO2 core-shell nanoparticles exhibited efficient photocatalytic degradation against MB with a photodegradation efficiency of 85 % under UV and 60 % under visible irradiation. Finally, the prepared nanocomposite particles were incorporated to an emulsion acrylic resin to prepare photocatalytic polymer film. The prepared films were evaluated for photocatalytic degradation of MB stain and mechanical performances. It was found that the TiO2@Silane@SiO2 nanocomposite particles that prepared by layer-by-layer method caused about 56 % improvement in hydrophobicity, 276.7 % increment in the tensile strength, 109.6 times enhancement in the modulus, 381.4 times enhancement in the toughness and 57.6 times improvement in the elongation at break of the acrylic film compared to the pure TiO2-containing acrylic film, respectively.