Gel Reaction Research Articles

Synchrotron Capabilities in a Laboratory Setting: In Situ X-Ray Absorption Spectroscopy of Disordered Vanadium Ferrite Electrodes for Lithium-Ion Batteries

X-ray absorption spectroscopy (XAS) provides important information on metal oxidation state andelement-specific coordination, but data collection has historically required the energy specificityand brilliance of a synchrotron facility. Recent developments in detectors and optics are nowbringing XAS capabilities to the laboratory setting through multiple commercially availableinstruments. At the U.S. Naval Research Laboratory, we use laboratory-based XAS to explore thelocal electronic and atomic structure of a class of disordered vanadium ferrite (VFe2Ox) aerogelsthat exhibit promising performance for electrochemical energy-storage applications such asrechargeable lithium-ion batteries.1,2 These materials are synthesized by an epoxide-promoted sol–gel reaction of iron chloride and vanadium isopropoxide, with the resulting fluid-filled gelsrendered as high surface area aerogels via supercritical-CO2 drying. During the initial sol–gelsynthesis, electroinactive metals such as aluminum, zinc, and zirconium may also be substitutedfor vanadium and iron to alter the local electronic environment and corresponding electrochemicalperformance of VFe2Ox. Heat treatment of as-dried VFe2Ox aerogels under either O2-containingor inert atmosphere yields disordered or nanocrystalline variants, respectively. The resulting seriesof native and substituted VFe2Ox materials are evaluated as powder-composite cathodes versuslithium metal in coin cells with conventional nonaqueous lithium-ion electrolyte. We correlatesuch critical battery-performance parameters as total specific capacity, high-rate capability, andcycle life as a function of VFe2Ox composition and its degree of structural order/disorder, asmeasured with in-situ XANES and EXAFS. In parallel with experimental observations,calculations on VFe2Ox reveal that V incorporates into the defective spinel structure at tetrahedralsites and that both disorder induced by vacancies and Fe/V tetrahedral occupation lowers theoverall energy and opens an electronic energy gap that establishes the redox sequence duringlithiation.1. C. N. Chervin, J. S. Ko, B. W. Miller, L. Dudek, A. N. Mansour, M. D. Donakowski, T.Brintlinger, P. Gogotsi, S. Chattopadhyay, T. Shibata, J. F. Parker, B. P. Hahn, D. R. Rolison,and J. W. Long, J. Mater. Chem. A 3, 12059 (2015).2. C. N. Chervin, R. H. DeBlock, J. F. Parker, B. M. Hudak, N. L. Skeele, J. S. Ko, D. R. Rolison,and J. W. Long, RSC Adv. 11, 14495 (2021).

Synthesis of Single Nanometer-Sized Au Nanoparticles Coated with Silica Toward X-Ray Contrast Agent

In this study, we proposed a method for fabricating diagnostic imaging nanoparticles composed of Au nanoparticles and silica shells (Au/SiO2). The proposed method consisted of two steps. The first step was the synthesis of Au nanoparticles. In sodium hydroxide (NaOH) solution, hydrogen tetrachloroaurate (III) trihydrate was reduced with tetrakis(hydroxymethyl)phosphonium chloride to synthesize Au nanoparticles with a diameter of 1.7 ± 0.3 nm. The Au nanoparticles were then coated with silica in the following step. The silica coating was achieved via a sol–gel reaction of tetraethyl orthosilicate in the presence of Au nanoparticles in water/ethanol dissolved in NaOH. The Au/SiO2 nanoparticles degraded faster in saline or phosphate-buffered saline than in water, and the X-ray imaging capability was retained.

A route toward fabrication of 3D printed bone scaffolds based on poly(vinyl alcohol)–chitosan/bioactive glass by sol–gel chemistry

Among different methods for the fabrication of bone scaffolds, 3D printing has created great advances in tissue engineering and regenerative medicine owing to its ability to make objects mimicking native tissues. Thanks to its abundant availability, structural features, and favorable biological properties, chitosan (CS) hydrogel was selected to be used for preparation of the bone scaffolds. However, the 3D printing of CS-based hydrogels is still under early exploration. Knowing the fact that natural polymers are not so competent at holding large amounts of water, poly(vinyl alcohol) as the second polymer was employed. The novelty of the present research lies in the concept of employing sol‐gel chemistry in order to attain proper viscosity and rheological behavior to give self-standing filaments of the polymer blends. Employing sol–gel reaction in the preparation of the hybrid hydrogels had the advantage of endowing shape fidelity to the polymer blend without any solidifying in the needle. The obtained organic-inorganic hybrids were directly printed and subsequently cross-linked. The best performance in terms of mechanical strength, cell viability, and bio-mineralization was observed for the 50:50 ratio. The in vitro cell culture and the bioactivity results showed that the printed scaffolds with this method have great potential in bone tissue engineering. Further, this method could be expandable to print other hydrogels with diverse applications such as implantable devices, soft robotics, etc.

Structural, dielectric, and electrochemical properties of pear-shaped CexLi2Zn0.5Mn0.5Ti3−xO8 supercapacitor: XRD and dielectric calculation

Complex nano-perovskite materials have recently gained attention as promising electrode materials for supercapacitors due to their high capacitances. The crystalline structure, dielectric properties, and electrochemical properties of LiZn0.5Mn0.5Ti3-xCexO8 (x = 0, 0.05, 0.1, & 0.15) pear-shaped nanoceramics, which were prepared through sol–gel reactions and sintered at 800 °C for 3 h, were explored. The XRD proves the well-crystalline structure for the prepared nanoceramic with the diffraction peaks corresponding to the cubic LiZnTi3O8 phase, the doped samples appearing with new peaks are matched to the cubic CeO2 phase. The impact of the Ce3+ ratio in the Li2Zn0.5Mn0.5Ti3O8 pear-shaped nanostructure on the dielectric properties of the nanoceramics is apparent, as the conductivity increases with increasing frequency and temperature. The electrochemical attitude can be ascribed to the LiZn0.5Mn0.5Ti3O8 pear-shaped nanostructure under the effect of Ce3+ ions producing continuous internal rearrangement. The capacitance values for Li2Zn0.5Mn0.5Ti3O8 doped with different ratios (3, 5, 10, 15%) Ce3+ are changed from 41.58 to 38.28 F.g-1, at scan rate (10) mVs-1. High electrocatalytic properties of the LiZn0.5Mn0.5Ti3-xCexO8 nanoceramics is approved using cyclic voltammetry, and electrochemical impedance spectroscopy. Furthermore, the Electrochemical analysis indicates that LiZn0.5Mn0.5Ti3-xCexO8 nanoceramics promising for supercapacitors applications.

Effect of molar concentration and drying methodologies on monodispersed silica sol for synthesis of silica aerogels with temperature-resistant characteristics

A variety of hierarchical nanoporous silica aerogels with diversified particle distributions were synthesized from well-dispersed silica sols by a traditional sol–gel method. Among the six particle sizes of aerogels, the silica aerogel with 0.4 M TEOS/MTMS surface modification and supercritical drying attains 11.61 ± 2.96 nm constituent part with well slender size particle dissemination, high-temperature confrontation and low thermal conductivity. In association with the outmoded two-step acid-base dilution of silica sols, the well-diffused form of silica sols with surface alteration also provides a low thermal conductivity of 0.01865 W.m−1 K−1 with greater thermal resistance. In addition, the drying shrinkage can be minimized with surface modification by properly silylation with TMCS. The concentrations of well-diffused silica sol were adjusted to achieve higher surface area, low density, large pore size and structure, and temperature resilience with the help of controlling the sol–gel reaction. The resilient skeleton structure developed from the assembly of tiny particles can efficiently restrict the glutinous heat dissipation between aerogel networks without collapsing a porous network up to a higher temperature of 900 °C. However, this network retains a similar pattern up to 1000 °C with only 32 % volume contraction after 2hr of heat treatments. At an elevated temperature of 1100–1200 °C, the viscid heat flow between nanoparticles and the porous network cannot be meritoriously suppressed and starts to collapse after a shorter duration. The enormous results of silica aerogels will help design suitable thermal insulation with higher resilience and low thermal conductivity.

Robust conductive nanocomposite hydrogels with an interpenetrating network based on polyaniline for flexible supercapacitors

AbstractConductive polyacrylic acid/polyaniline/SiO2 (PAA/PANI/SiO2) nanocomposite hydrogels as electrolytes for a high‐performance flexible supercapacitor were prepared by combining in situ radical polymerization of anionic monomer acrylic acid, in situ sol–gel reaction of vinyltriethoxysilane (VTES), and oxidative polymerization of conductive monomer aniline (ANI). In the nanocomposite hydrogel, vinyl‐SiO2 nanoparticles served as analogous covalent crosslinkers, while the reversible noncovalent interactions (such as hydrogen bonds, electrostatic interactions, and chain entanglements) between the PAA/SiO2 and PANI networks acted as physical crosslinkers. The interconnected PANI and PAA/SiO2 networks thus constructed an interpenetrating three‐dimensional network that improved the movement of electrons and ions while also enhancing the mechanical properties of the hydrogel. At a volume ratio of ANI to VTES of 50:200, the compressive strength and conductivity of PAA/PANI/SiO2 hydrogels were as high as 1505 kPa and 4.42 S/m, respectively. Moreover, the flexible supercapacitors based on the nanocomposite hydrogel electrolyte exhibited high specific capacitance (574.7 F/g), energy density (19.6 Wh/kg), and power density (1.4 kW/kg) at a current density of 0.05 A/g. Meanwhile, these supercapacitors exhibit exceptional flexibility and mechanical stability, and can be repeatedly bent without degrading performance. This nanocomposite hydrogel has considerable potential for use in other flexible energy devices and electronics due to its excellent mechanical and electrochemical properties.Highlights Conductive nanocomposite hydrogel have good conductivity and mechanical properties. Conductive hydrogels are used as electrolytes for flexible supercapacitors. Vinyl‐SiO2 served as analogous covalent crosslinkers for the hydrogel. Noncovalent bonds between PAA/SiO2 and PANI acted as physical crosslinkers. Interconnected PANI and PAA/SiO2 networks formed an interpenetrating network.

High early pozzolanic reactivity of alumina-silica gel: A study of the hydration of composite cements with carbonated recycled concrete paste

Carbonated recycled concrete paste (cRCP) is a unique supplementary cementitious material with pozzolanic properties stemming from the alumina-silica gel. This study reveals that the high early strength of composite cements with cRCP is attributed to its rapid pozzolanic reactivity. 27Al and 29Si NMR investigations show that the alumina-silica gel is consumed after only 7 days of hydration. The rapid gel reaction results in the formation of a C-(A)-S-H phase with a low Ca/Si ratio. After 7 days, belite and remains of alite react further and increases the Ca/Si ratio of the C-(A)-S-H phase to a level typical for blended cements. As a result, a lower porosity forms already at early age, resulting in high strength. The reactivity of cRCP is influenced by its origin and carbonation conditions. Carbonation in sulfate-rich solutions enhances the gel surface area and accelerates the reaction. Slag remnants in cRCP react aiding to microstructure and strength development.

Portable paper-based molecularly imprinted sensor for visual real-time detection of influenza virus H5N1

The rapid detection of pathogens is important to the control of epidemics. Here, a paper-based molecularly imprinted sensor has been developed for the visual detection of influenza H5N1 virus. Firstly, the paper-based molecularly imprinted was prepared by a sol–gel reaction. Then, H5N1 ∼ Apt was covalently bound to the surface of the ZIF-8-NH2 coated with rhodamine B (RhB) through an amide bond, to produce the fluorescent and colorimetric probe ZIF-8-NH2@RhB ∼ Apt. When H5N1 and ZIF-8-NH2@RhB ∼ Apt are added to the paper-based MIPs, the H5N1 will be combined with MIPs through the synergistic effects of shape and size compatibility and interaction with the functional groups of the monomers, and ZIF-8-NH2@RhB ∼ Apt will bind to H5N1 through its aptamers to form a sandwich structure. The sensor has ultra-high sensitivity and the detection limit is 0.58 fmol/L by using fluorescence spectroscopy. A semi-quantitative signal can also be observed with the naked eye within 10 min. A comparative study showed that direct visual detection was highly reliable, and the sensitivity was better than that achieved with a commercially available kit. Importantly, the paper-based sensor is low in produce cost (Original size: RMB 1.53 Yuan each; Smaller size: RMB 0.08 Yuan each) and is easy to cut, store and carry. This sensor is expected to allow self-service, visual, high-throughput, and real-time virus detection, which is of great significance for epidemic prevention and control.

CoCr2O4/Graphene modified glass carbon electrode for highly dual-sensing detection of hydrogen peroxide and glucose

The development of a non-enzymatic electrochemical sensor possessing well dual-sensing to H2O2 and glucose remains challenging due to less report. Herein, spinel CoCr2O4 nanoparticles with small size were synthesized by sol–gel reaction, which were then simply mixed with commercial graphene under ultrasonic to obtain uniformly dispersed CoCr2O4/Graphene composite. They were deposited onto the surface of bare glassy carbon electrode (GCE) through a common drop-coating method. The CoCr2O4/Graphene/GCE sensor firstly achieves highly dual-sensing to H2O2 and glucose in 0.1 M NaOH solution. At 0.4 and 0.55 V, its sensitivities to H2O2 and glucose can separately reach up to 1168.6 and 1722.5 μA mM−1 cm−2, and the corresponding detection limits are as low as 18 nM and 12 nM. These key indexes are the best among reported dual-functional spinel oxide-based electrodes. This excellent electrochemical sensing ability stems from its large electrode active area, good conductivity, and the synergism between graphene and CoCr2O4 nanoparticles with mixed redox couplings, which provides an efficient platform for dual-sensing detection. In addition, the modified electrode can accurately determine glucose in human tears, rat serum and orange juice, as well as H2O2 in milk whey, mouthwash and disinfectant, thus predicting its good application prospects.

A Composite of Polyether Ether Ketone and Silica‐Coated Copper Particles for Creating Tailored Conductive Tracks via Laser Printing

AbstractConventional substrates for optoelectronic systems include inorganic or organic carrier materials; however, these systems are typically subjected to environmentally harmful multistep processes to prepare printed circuit boards. To mitigate these issues, the present article reports a polyether ether ketone (PEEK)‐based composite densely filled with copper microparticles, prepared using a simple, cost‐effective, and sustainable synthesis method. The material exhibits high thermal conductivity but is electrically nonconductive prior to undergoing laser treatment. To prevent the composite from exhibiting electrical conductivity, the copper particles are coated with a thin silica layer through a sol–gel reaction. The thermal stability of PEEK and the Cu–PEEK composites with Cu contents of up to 70 vol%, which are prepared via heat melding, is investigated by thermogravimetric analysis, differential scanning calorimetry, and Fourier‐transform infrared spectroscopy to clarify the manner in which copper affects the chemical structure of the polymer. The developed composite exhibits a significantly higher thermal conductivity than that of the unfilled PEEK polymer. This paper also describes the effects of laser treatment on the surface morphology. Overall, this study suggests that conductive tracks with low electrical resistance can be created on electrically insulating substrates with high thermal conductivity.

BZT substitution effect on the characteristics of (1-x) MT – x BZT composite ceramics synthesized by the sol–gel method

This paper addresses a crucial gap in the effect of adding BaZr0.1Ti0.9O3 (BZT) on the structural, microstructural, dielectric, and electrical properties of MgTiO3 (MT) material. These ceramics with the chemical composition (1-x) MT – x BZT were synthesized with different compositions ranging from × = 0.0 to 1.0 with a 0.1 step using the sol–gel reaction process. The X-ray diffraction (XRD) results and Rietveld refinement analysis showed the formation of a tetragonal phase with the P4mm space group for the BZT sample and a hexagonal phase with the R-3 space group for MT ceramics, without any secondary phases. However, (1-x) MT – x BZT composites with × ranging from × = 0.1 to 0.9, showed a coexistence of tetragonal (P4mm) and hexagonal (R-3) phases. Scanning Electron Microscopy (SEM) was used to investigate the morphology and grain size of the compounds. The SEM results revealed a clear decrease in grain growth for x = 0.6 of BZT content with the higher density. Furthermore, the dielectric properties of these composites were studied by impedance spectroscopy, which showed a single diffuse dielectric phase transition for all the BZT-MT composites. There was a clear increase in dielectric permittivity (εr′) value with the increase of the BZT content. This broad phase transition is highly desired and has not been observed in previous studies. The obtained composite ceramics could open the way to lead new applications in microelectronic devices.

BaO as a heterogeneous nanoparticle catalyst in oil transesterification for the production of FAME fuel

Metal oxide-based catalysts play an important role in the transesterification reaction of vegetable oils for fatty acid methyl ester (FAME) production. Additionally, nanocatalysts demonstrate high efficiency due to their increased surface area, higher catalytic activity, and easy operational procedures. Thus, the main objective of this work is to investigate FAME production from sunflower oil using barium oxide (BaO) nanoparticles. BaO was synthesized through one-pot sol–gel reactions and was analysed by several techniques, such as X-ray diffraction (XRD), transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence(EDXRF), N2 adsorption–desorption of liquid nitrogen at 77 K [Brunner–Emmett–Teller (BET)] for surface area measurement and UV–Vis spectroscopy. BaO behaved as an efficient catalyst in the transesterification of oils into FAMEs. Furthermore, the impacts of a variety of reaction parameters on the biofuel yield were explored. The catalyst with 4.7 wt% has the maximum yield of 78.38 % achieved under the optimized reaction conditions (70 °C, 1:20 M ratio of oil:methanol). The characteristics of the resulting methyl ester partially agreed with international FAME standards, making it suitable for use as a blend with petroleum diesel in proportions defined by volume according to the specifications of the American Society for Testing and Materials(ASTM). The catalyst was also evaluated for reusability tests, and the reusability through the reaction showed less than a 7 % conversion drop after 3 runs and 14.6 % after 5 runs.

Impact of varying Li+ concentration on the upconversion emission and temperature sensing characteristics of YVO4: Tm3+/Yb3+ phosphor

A series of Li+ codoped YVO4: Tm3+/Yb3+ phosphors were prepared by Pechini sol–gel reaction technique. Structural study of the material confirms the crystal structure of the prepared samples and also gives information about the crystallite size and phase purity with the variation of Li+ ion concentrations. Emission peaks around ∼ 476, and ∼ 799 nm corresponds to the 1G4→3H6, and 3H4→3H6 transitions, which could be seen under irradiation of NIR (980 nm) laser light. Li+ (10 mol%) codoped sample shows maximum upconversion. Li+ doping significantly increases the up-conversion emission intensities by more than 5 times for emission peaks around 476 nm and 799 nm.The possible explanation for the increase in UC (Upconversion) emission intensity is attributed to both improved crystallinity and crystal field modification around Tm3+ ions. The variation of UC emission spectra with respect to pump power was observed to investigate the underlying UC luminescent mechanism in YVO4: Tm3+/Yb3+ codoped with Li+ (10 mol%). The multiphoton involvement is observed in the power-dependent study of upconverted blue and NIR emission bands. Widely used fluorescence intensity ratio (FIR) technique was used to evaluate the temperature sensing capability of the optimized Li+ codoped phosphor. The FIR study of Stark components 3F2, and 3H4 levels indicates that this material is an efficient material for temperature sensing. The optimized sample, doped with Li+, exhibits relative sensitivity of 0.78% K−1 at a temperature of 548 K. This material have utility in both light-emitting diodes and as a temperature-sensing probe.

Chitosan–Resole–Pectin Aerogel in Methylene Blue Removal: Modeling and Optimization Using an Artificial Neuron Network

In this study, a novel chitosan–resole–pectin aerogel (CS–R–P) was created from a sol–gel reaction with a solution of Cs and P with resole by a freeze-drying technique, and this adsorbent was proposed for the removal of methylene blue (MB). In addition, with the use of an artificial intelligence technique known as an artificial neural network (ANN), this material was modeled and optimized. Its physical morphology and chemical composition were also characterized with FTIR and XPS, and its adsorption properties were analyzed. For modeling the adsorption process, three main parameters were used: the chitosan–resole–pectin concentration (45–75%), thermal treatment (6–36 h), and known concentrations of methylene blue (25–50 and 100 mg/L), established on the Box–Behnken design. The ANN was coupled with the improved gray wolf optimization (IWGO) metaheuristic algorithm, achieving a correlation coefficient of R2 = 0.99. The characterization indicates that the surface of the aerogels was micro- and mesoporous, the resole gave physical stability, and the polysaccharide base delivered the functional groups necessary for dye adsorption; the aerogels were successful dye adsorbents with a qe of 12.44 mg/g. Finally, the physical and chemical sorption was ascertainable with an adsorption that followed pseudo-second-order kinetics. The MB adsorption was clearly occurring though cation exchange and hydrogen binding as observed in the chemical composition. The ANN with the gray wolf optimizer was used for the prediction of the best operating parameters for MB removal, applying the following conditions—the CS–R–P aerogel concentration (52/30/18), the thermal treatment (9.12 h), and the initial concentration of methylene blue (37 mg/L)—achieving a 94.6% removal. These conclusions suggest that using artificial intelligence such as an ANN can provide an efficient and practical model for maximizing the removal action of new aerogels based on chitosan.

Organocatalytic Asymmetric Domino [3+2]-Cycloaddition-Acyl Transfer Reaction between Azomethine Ylides and α-Nitro-α,β-Unsaturated Ketones.

Here in we have developed an organocatalytic asymmetric domino [3+2]-cycloaddition-acyl transfer reaction between in situ generated azomethine ylides and α-nitro-α,β-unsaturated ketones. The desired penta-substituted pyrrolidine products were obtained in high yields and in moderate to good enantio- and diastereoselectivities. Also, an isomerization reaction in silica gel was performed for the formation of another diastereomer in high yields with retention of enantioselectivities.

Uncovering Electrochemical Cation-Storage Mechanisms in Defective Vanadium Ferrites Using Synchrotron-Quality, in-Lab X-Ray Absorption Spectroscopy

X-ray absorption spectroscopy (XAS) is a critical tool for investigating new materials for electrochemical energy storage, providing important information on metal oxidation state and element-specific coordination. Historically, XAS measurements had required the energy specificity and brilliance of a synchrotron facility, but recent advances in detectors and optics are bringing XAS capabilities to the laboratory setting with multiple commercial instruments available. At the Naval Research Laboratory, we use laboratory-based XAS to study a class of disordered vanadium ferrite (VFe2Ox) aerogels that exhibit promising performance for electrochemical energy-storage applications such as rechargeable lithium-ion batteries.1,2 The structure and composition of these materials are readily varied via modifications to the epoxide-promoted sol–gel reaction of iron chloride and vanadium isopropoxide (e.g., substitution with other cations such as Al3+),2 as well as post-synthesis thermal treatments that render disordered, defective, or nanocrystalline forms of a given composition. The resulting series of VFe2Ox materials are evaluated by XAS in both ex situ and in situ configurations, including as powder-composite cathodes versus lithium metal in pouch cells with conventional nonaqueous lithium-ion electrolyte. X-ray Absorption Near-edge Spectroscopy (XANES) at the V K-edge and Fe K-edge is used to track V and Fe oxidation state, respectively, permitting the assignment of metal-centered redox across the broad potential range over which these materials are electrochemically active (2–3.4 V vs Li/Li+). Extended X-ray Absorption Fine Structure (EXAFS) analysis provides information on V- or Fe-specific coordination as a function of composition, structure, and state-of-charge. Parallel computation efforts using Density-Functional Theory offer a complementary feedback loop with experimental XANES and EXAFS to achieve a sophisticated description of these complex battery materials.1. C. N. Chervin, J. S. Ko, B. W. Miller, L. Dudek, A. N. Mansour, M. D. Donakowski, T.Brintlinger, P. Gogotsi, S. Chattopadhyay, T. Shibata, J. F. Parker, B. P. Hahn, D. R.Rolison, and J. W. Long, J. Mater. Chem. A 3, 12059 (2015).2. C. N. Chervin, R. H. DeBlock, J. F. Parker, B. M. Hudak, N. L. Skeele, J. S. Ko, D. R.Rolison, and J. W. Long, RSC Adv. 11, 14495 (2021).

Synthesis of Polystyrene@TiO2 Core–Shell Particles and Their Photocatalytic Activity for the Decomposition of Methylene Blue

In this study, we investigated the preparation conditions of polystyrene (PS)@TiO2 core–shell particles and their photocatalytic activity during the decomposition of methylene blue (MB). TiO2 shells were formed on the surfaces of PS particles using the sol–gel method. Homogeneous PS@TiO2 core–shell particles were obtained using an aqueous NH3 solution as the promoter of the sol–gel reaction and stirred at room temperature. This investigation revealed that the temperature and amount of the sol–gel reaction promoter influenced the morphology of the PS@TiO2 core–shell particles. The TiO2 shell thickness of the PS@TiO2 core–shell particles was approximately 5 nm, as observed using transmission electron microscopy. Additionally, Ti elements were detected on the surfaces of the PS@TiO2 core–shell particles using energy-dispersive X-ray spectroscopy analysis. The PS@TiO2 core–shell particles were used in MB decomposition to evaluate their photocatalytic activities. For comparison, we utilized commercial P25 and TiO2 particles prepared using the sol–gel method. The results showed that the PS@TiO2 core–shell particles exhibited higher activity than that of the compared samples.

Results of the implementation of sanitation measures in the farms unfavorable for bovine leukemia

The dynamics of recuperation work on the example of two farms similar in economic and production and technological characteristics of the Novosibirsk region were studied. The data on leukemia at the time of the beginning of active recuperation work and the results after several years were presented. The infection rates of the livestock by different age groups and in different parts of the studied farms were analyzed for 2017-2022. The infection rate of cows on the farms tended to decrease slightly from 2017 to 2019 and was in the range of 8-4%. The infection rate of the heifers was 5-12%. Registration of new cases of serology response in the group of the calves in the farm No. 1 decreased from 9.9 to 4.9%, in the farm No. 2 from 14.2 to 7.1%. The positive dynamics of implementation of the recovery plan using enzyme-linked immunosorbent assay (ELISA) for serological diagnosis was shown. After switching from the immunodiffusion in agar gel reaction (AGID) to ELISA and its first use, the number of newly detected animals increased in all age groups in both farms compared to the previous period. In subsequent studies, the percentage of new cases decreased significantly. Physical separation of the groups of animals with different statuses, placing them in different sections and clear control with the immediate exclusion of infected animals from the production process led to a noticeable improvement in the epizootic situation on the farm. Aspects causing delay in sanitation work were noted, in particular, untimely separation of animals into groups after serological diagnosis and establishment of their infection status. Complete replacement of infected cattle in unhealthy herds or wards by groups of serology-negative animals can significantly reduce the recovery period, especially at the final stage.

Synthesis and application of nano-silicon prepared from rice husk with the hydrothermal method and its use for anode lithium-ion batteries

Nano-silicon is synthesized by hydrothermal method from rice husk, which has the advantage of using low temperature in an autoclave at 180 °C. Reduction of silica using a mixture of silica gel extracted from rice husks with Mg powder. The silica gel and Mg powder reaction produces nano-silicon. XRD diffractogram, it can be seen that Si-0.5, Si-0.6, and Si-0.7 form hkl (111), (220), (311), (400), (331), and (422). Raman spectra show peaks at the Raman shift of 520 cm−1, XPS spectrum high scan Si2p peaks at 99 eV, indicating silicon, and at 103 eV, the oxide layer on nano-silicon. The isotherm adsorption graph using the BET method type IV isotherm graphs with surface areas are 18.60 m2g−1 until 20.39 m2g−1. Pore size using the BJH method shows 1.69 nm until 8.30 nm. SEM and TEM nano-silicon morphology images, the shape of the nano-silicon is spherical. The nano-silicon formed produces high-performance anode lithium-ion batteries with a discharge capacity of 1757 mAh g−1, above 1000 mAh g−1 for approximately 200 cycles.

Increase in volume stability of RO phases in steel slag by combined treatment of alkali and dry carbonation

RO phases account for 8.5–16.9 wt% of steel slags and exhibit delayed hydration activity, which may result in poor volume stability of steel slags (SS). Treatment of alkali activator (sodium silicate) followed by dry carbonation technology (ADC) was conducted on synthetic RO phases with various molar ratios of FeO, MgO, and MnO to promote its early hydration activity. Results show that 28 d compressive strength of mortar added by ADC_SS is 19.67% higher than that of added untreated SS and 26% decrease in expansion rate. Hydration degree of RO phases increases obviously during alkali treatment from 10.6% to 21.7% (RO-6), and is further stimulated by subsequently carbonation (reaching 44.1%), both resulting in much consumption of expansive component (i.e., MgO) in RO phases. The early hydration activity of cement promoted by adding ADC_RO phase/SS, which mainly attributes to the nucleation effect of hydration and carbonation products (i.e., Mg(OH)2, pyoaurite, and MgCO3·3H2O). The alkali excitation reaction of silica gels produced during carbonation as well as the formation of monocarboaluminate further contribute to the strength gain. ADC_SS used as admixture for cement makes pastes have advantage of higher strength, higher hydration rate, lower heat release, and less expansion rate compared to the system contained untreated SS. ADC may be a potential method to treat SS and makes SS to be used as admixture for Portland cement.