Maximizing Photoelectrochemical Performance in Metal-Oxide Hybrid Composites via Amorphous Exsolution-A New Exsolution Mechanism for Heterogeneous Catalysis.

Exsolution generates metal nanoparticles anchored within crystalline oxide supports, ensuring efficient exposure, uniform dispersion, and strong nanoparticle-perovskite interactions. Increased doping level in the perovskite is essential for further enhancing performance in renewable energy applications; however, this is constrained by limited surface exsolution, structural instability, and sluggish charge transfer. Here, hybrid composites are fabricated by vacuum-annealing a solution containing SrTiO3 photoanode and Co cocatalyst precursors for photoelectrochemical water-splitting. In situ transmission electron microscopy identifies uniform, high-density Co particles exsolving from amorphous SrTiO3 films, followed by film-crystallization at elevated temperatures. This unique process extracts entire Co dopants with complete structural stability, even at Co doping levels exceeding 30%, and upon air exposure, the Co particles embedded in the film oxidize to CoO, forming a Schottky junction at the interface. These conditions maximize photoelectrochemical activity and stability, surpassing those achieved by Co post-deposition and Co exsolution from crystalline oxides. Theoretical calculations demonstrate in the amorphous state, dopant─O bonds become weaker while Ti─O bonds remain strong, promoting selective exsolution. As expected from the calculations, nearly all of the 30% Fe dopants exsolve from SrTiO3 in an H2 environment, despite the strong Fe─O bond's low exsolution tendency. These analyses unravel the mechanisms driving the amorphous exsolution.

One-Step Photochemical Preparation of CdS/Poly(MMA-co-MAA) Composite with Enhanced Photocatalytic Activity.

This paper presents a one-step photochemical method for the preparation of CdS/Poly(MMA-co-MAA) composite photocatalyst, based on the concept of simultaneous photocatalytic polymerization of organic monomers during UV-light induced formation of CdS. The preparation is carried out in an aqueous solution of Na2S2O3, CdSO4, methyl methacrylate (MMA) and methacrylic acid (MAA), under a UV lamp. The continuously formed CdS particles with photocatalytic activity act the role of initiator to directly initiate the copolymerization of MMA and MAA, resulting in the in situ formation of the composite and full contact of the CdS particles with the oxygen-containing groups in the polymer. Taking the photocatalytic degradation of methylene blue as a case study, the composite exhibited significantly higher activity under simulated solar light compared to the pure CdS. By analysis on various data, the enhanced photocatalytic activity is attributed to the enhanced visible light absorption, and especially the high electron-hole separation efficiency caused by the electrostatic interaction between photogenerated holes and carbonyl oxygen atoms with negatively charged features. Furthermore, the composite displays excellent sunlight activity and recyclability, suggesting its potential for practical applications. Such a one-step construction strategy relying only on photo-energy is green, low-cost and promising in obtaining high-performance semiconductor/polymer composite photocatalysts.

Fracture strength of preformed zirconia crown and CAD-CAM zirconia, ceramic, and hybrid composite crowns for the restoration of primary molars: An in vitro study.

BACKGROUND: Paediatric-preformed zirconia crowns have been associated with several issues, primarily their inability to be crimped and the need for extensive tooth preparation. Additionally, the capacity to adjust the size, shape, and fit of these crowns is very limited. AIM: To evaluate and compare the fracture strength of four different types of dental crowns intended for paediatric patients. DESIGN: The fracture resistance of four types of paediatric crowns was evaluated using the universal testing machine; freshly extracted primary molars received one of the following: preformed zirconia crowns, custom-made computer-aided design and computer-aided manufacturing (CAD-CAM) zirconia crowns, custom-made CAD-CAM ceramic crowns, and custom-made CAD-CAM hybrid composite crowns. Data were statistically compared using the Kruskal-Wallis test followed by the Bonferroni test, and the level of significance was set at 5%. RESULTS: Results showed that there was a statistically significant difference among the four groups (p < .001). The highest value of fracture force was observed for the milled zirconia crown and the lowest for the prefabricated zirconia. CONCLUSION: The implementation of the CAD-CAM digital crown fabrication technique has the potential to address issues associated with preformed crowns in paediatric patients, particularly in terms of fracture resistance.

Two­year clinical performance of indirect restorations fabricated from CAD/CAM nano hybrid composite versus lithium disilicate in mutilated vital teeth. A randomized controlled trial.

TRIAL DESIGN: This is a randomized, controlled, superiority, double-blinded, parallel-group, two-arms trial with an allocation ratio of 1:1. The aim of this trial was to compare the two-year clinical performance of partial indirect restorations fabricated from CAD/CAM nano-hybrid composite and ceramic lithium disilicate blocks using the modified USPHS criteria. METHODS: In two parallel groups (n = 50 restorations), fifty participants having mutilated vital teeth with a minimum of two remaining walls were randomly enrolled in this trial and received indirect restorations of either nano-hybrid composite resin blocks (Brilliant, Coltene, Switzerland) or Lithium Disilicate (IPS Emax CAD). The restorations were assessed using modified USPHS criteria by two independent blinded assessors at baseline, six months, one-year and two years follow-up visits. Categorical and ordinal data were presented as frequencies and percentages. Categorical data were analyzed using the chi-square test. Ordinal data were analyzed using the Mann-Whitney U test for intergroup comparisons and Freidman's test followed by the Nemenyi post hoc test for intragroup comparisons. Numerical data were presented as mean and standard deviation values. They were analyzed for normality using the Shapiro-Wilk test. Data were found to be normally distributed and were analyzed using the independent t-test. The significance level was set at p ≤ 0.05 within all tests. RESULTS: Forty-eight participants received the allocated intervention and completed the follow-up periods. There was a statistically significant difference between both tested materials for all USPHS criteria regarding Marginal integrity and Marginal discoloration at six-months Follow-up, but with no statistically significant difference at one- and two-year follow-up. CONCLUSIONS: Both materials showed an acceptable, successful clinical performance along the two-years follow-up period. CLINICAL RELEVANCE: The CAD/CAM nano-hybrid composite blocks are as reliable as Lithium disilicate for restoring mutilated vital teeth.

Bio-mimetic selectivity in Hg2+ sensing developed via electro-copolymerized PEDOT and benzothiazole-Au nanoparticles composite.

To eliminate the potential health risks of mercury, development of stable and selective mercury sensor with high sensitivity is the need of the hour. To address this, a novel PEDOT-AA-BTZ-Au-based Hg2+ selective, hybrid electrochemical sensor has been designed by following a simple protocol for electrode fabrication. The electrode was designed by carefully optimizing the onset oxidation potential of supramolecule 2-(anthracen-9-yl)benzo[d]thiazole (AA-BTZ) and conducting polymer poly-(3,4-ethylenedioxythiophene) (PEDOT), using copolymerization approach followed by dropcasting of gold nanoparticles (AuNPs). The designed electrode offered synergistic effects thus augmenting the electrical conductivity and adsorption capacity as depicted by its porous surface morphology. The highly sensitive analytical signal was generated by sulphur pockets present in AA-BTZ and PEDOT conducting framework. This is further complemented by the selectivity offered by the soft interactions between AuNPs and Hg2+ resulting in a low detection limit of 0.60 nM. The prepared system was further utilized for sensing Hg2+ ion in real systems including lake water and cosmetic samples. Low interference from other ions and better reproducibility further established the suitability of the designed transducer system for future on-site sensing.

Hybrid Composite of Sn(IV)-Porphyrin and Mesoporous Structure for Enhanced Visible Light Photocatalytic Degradation of Organic Dyes.

Two hybrid composites (SnP@MCM-41 and SnP@SiO2) were fabricated by chemical adsorption of (trans-dihydroxo)(5,10,15,20-tetraphenylporphyrinato)tin(IV) (SnP) on mesoporous structured Mobil Composition of Matter No. 41 (MCM-41) and SiO2 nanoparticles. These materials were characterized by Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, fluorescence spectroscopy, transmission electron microscopy, and field-emission scanning electron microscopy techniques. The incorporation of SnP into MCM-41 and SiO2 supports efficient photocatalytic degradation of the anionic erioglaucine, cationic rhodamine B, and neutral m-cresol purple dyes under visible light irradiation in an aqueous solution. The performances of degradation of these dyes by these photocatalysts under visible light irradiation varied from 87 to 95%. The pseudo-first-order degradation rate constant of organic dyes for SnP@MCM-41 was higher than those of SnP@SiO2 and SnP. These visible light photocatalysts showed remarkable stability and reliable reusability.

Surface Modification of ZnO with Sn(IV)-Porphyrin for Enhanced Visible Light Photocatalytic Degradation of Amaranth Dye.

Two hybrid composite photocatalysts, denoted as SnP/AA@ZnO and SnP@ZnO, were fabricated by a reaction of trans-dihydroxo[5,10,15,20-tetrakis(4-pyridyl)porphyrinato]tin(IV) (SnP) and ZnO with and without pretreatment of adipic acid (AA), respectively. In SnP@ZnO, SnP and ZnO are likely held together by a coordinative interaction between the pyridyl N atoms of SnP and the Zn atoms on the surface of ZnO. In the case of SnP/AA@ZnO, the SnP centers were robustly coupled with ZnO nanoparticles through the AA anchors. SnP/AA@ZnO exhibited largely enhanced photocatalytic activities for the degradation of anionic amaranth (AM) dye under a visible light irradiation, compared to SnP, ZnO, and SnP@ZnO. The degradation efficiency of AM by SnP/AA@ZnO was 95% within 60 min at a rate constant of 0.048 min-1. The remarkable photocatalytic oxidation performance of SnP/AA@ZnO was mainly attributed to the synergistic effect between SnP and ZnO. This study is valuable for the development of highly effective composite photocatalytic systems in advanced oxidation processes and is of importance for the treatment of wastewater containing dyes.

Mn3O4 nano-octahedrons embedded in nitrogen-doped graphene oxide as potent anode material for lithium-ion batteries.

Mn3O4 nano-octahedrons embedded in N-doped graphene oxide (MNGO) nanosheets were synthesized using a simple, energy-efficient, and rapid microwave-digested hydrothermal route in a single step. The structural and morphological aspects of synthesized materials were evaluated by XRD, IR, Raman, FE-SEM, and HR-TEM techniques. Then, the composite MNGO was tested for its Li-ion storage properties and compared with reduced graphene oxide (rGO) and Mn3O4 materials. The MNGO composite exhibited superior reversible specific capacity, excellent cyclic stability, and outstanding structural integrity throughout the electrochemical studies. The MNGO composite showed a reversible capacity of 898 mA h g-1 after 100 cycles at 100 mA g-1 and Coulombic efficiency of 97.8%. Even at a higher current density of 500 mA g-1, it exhibits a higher specific capacity of 532 mA h g-1 (~1.5 times higher than commercial graphite anode). These results demonstrate that Mn3O4 nano-octahedrons embedded on N-doped GO are a highly durable and potent anode material for LIBs. Supplementary Information: The online version contains supplementary material available at 10.1007/s11581-023-05035-6.

Materials Formed by Combining Inorganic Glasses and Metal-Organic Frameworks.

Here, we propose the combination of glassy or crystalline metal-organic frameworks (MOFs) with inorganic glasses to create novel hybrid composites and blends.The motivation behind this new composite approach is to improve the processability issues and mechanical performance of MOFs, whilst maintaining their ubiquitous properties. Herein, the precepts of successful composite formation and pairing of MOF and glass MOFs with inorganic glasses are presented. Focus is also given to the synthetic routes to such materials and the challenges anticipated in both their production and characterisation. Depending on their chemical nature, materials are classified as crystalline MOF-glass composites and blends. Additionally, the potential properties and applications of these two classes of materials are considered, the key aim being the retention of beneficial properties of both components, whilst circumventing their respective drawbacks.

Trap Inlaid Cationic Hybrid Composite Material for Efficient Segregation of Toxic Chemicals from Water.

Metal-based oxoanions are potentially toxic pollutants that can cause serious water pollution. Therefore, the segregation of such species has recently received significant research attention. Even though several adsorbents have been employed for effective management of chemicals, their limited microporous nature along with non-monolithic applicability has thwarted their large-scale real-time application. Herein, we developed a unique anion exchangeable hybrid composite aerogel material (IPcomp-6), integrating a stable cationic metal-organic polyhedron with a hierarchically porous metal-organic gel. The composite scavenger demonstrated a highly selective and very fast segregation efficiency for various hazardous oxoanions such as, HAsO42- , SeO42- , ReO4- , CrO42- , MnO4- , in water, in the presence of 100-fold excess of other coexisting anions. The material was able to selectively eliminate trace HAsO42- even at low concentration to well below the AsV limit in drinking water defined by WHO.

Hybrid nanostructures of Pd-WO3 grown on graphitic carbon nitride for trace level electrochemical detection of paraoxon-ethyl.

Well-defined crystal structures of Pd-doped WO3 nanorods were assembled on graphitic carbon sheets (Pd-WO3/g-C3N4) for ultrasensitive detection of paraoxon-ethyl (PEL) using an electrochemical method. The electrochemical behavior of PEL on the Pd-WO3/g-C3N4 hybrid composite was investigated using cyclic voltammetry (CV) and amperometric techniques. The Pd-WO3 crystallite was seen to modify the kinetics of g-C3N4, which improved the reduction/redox peak currents of PEL at the Pd-WO3/g-C3N4 composite compared to those of the g-C3N4 and WO3/g-C3N4-modified electrode. Moreover, the π-π interaction and hydrogen bond between the PEL and Pd-WO3/g-C3N4 composite improved the charge-transfer properties. The Pd-WO3/g-C3N4 hybrid composite was therefore able to obtain an enhanced sensitivity (3.70 ± 0.05 µA µM-1 cm-2) and low detection limit (0.03 nM; S/N = 3) with a wide range of linear concentrations (0.01-60 and 80-900.0 ± 5 µM) at applied potential of - 0.63 V (vs. Ag/AgCl). The detection of PEL in agricultural water and soil samples was successfully demonstrated with satisfactory RSD of 2.5 to 3.1% and recovery results of 97 to 102%, respectively.

Carbon Nanotube Fibers Decorated with MnO2 for Wire-Shaped Supercapacitor.

Fibers made from CNTs (CNT fibers) have the potential to form high-strength, lightweight materials with superior electrical conductivity. CNT fibers have attracted great attention in relation to various applications, in particular as conductive electrodes in energy applications, such as capacitors, lithium-ion batteries, and solar cells. Among these, wire-shaped supercapacitors demonstrate various advantages for use in lightweight and wearable electronics. However, making electrodes with uniform structures and desirable electrochemical performances still remains a challenge. In this study, dry-spun CNT fibers from CNT carpets were homogeneously loaded with MnO2 nanoflakes through the treatment of KMnO4. These functionalized fibers were systematically characterized in terms of their morphology, surface and mechanical properties, and electrochemical performance. The resulting MnO2-CNT fiber electrode showed high specific capacitance (231.3 F/g) in a Na2SO4 electrolyte, 23 times higher than the specific capacitance of the bare CNT fibers. The symmetric wire-shaped supercapacitor composed of CNT-MnO2 fiber electrodes and a PVA/H3PO4 electrolyte possesses an energy density of 86 nWh/cm and good cycling performance. Combined with its light weight and high flexibility, this CNT-based wire-shaped supercapacitor shows promise for applications in flexible and wearable energy storage devices.

Effect of pressure and light curing of composite micro hardness.

The aim of this study is to evaluate the micro hardness Vickers of a composite micro hybrid polymerized under constant pressure. Twelve experimental samples were made equally divided into two groups: an experimental group and a control. Enamel plus HRi (Micerium) microbiotic composite resin, UD3 colour, was inserted into a syringe heater (ENA HEAT Composite Heating Conditioner) so that the material could be brought to a temperature of 39°C. A defined amount of composite resin is taken from the syringe with a Heidemann spatula and placed between two slides, previously cleaned with 90 ° alcohol. The samples are then inserted one at a time into a special device for constant pressure application. Vickers hardness measurements were made on the top of surfaces. The mean value of the samples belonging to the experimental group is 56.81 ± 0.71. The mean value of the control samples is 52.02 ± 2. The results obtained allow us to state that applying a constant pressure during the cementation phase of indirect adhesive restorations allows to obtain better mechanical characteristics of the composite used as a cementing agent.

Sensing Exposure Time to Oxygen by Applying a Percolation-Induced Principle.

The determination of food freshness along manufacturer-to-consumer transportation lines is a challenging problem that calls for cheap, simple, reliable, and nontoxic sensors inside food packaging. We present a novel approach for oxygen sensing in which the exposure time to oxygen-rather than the oxygen concentration per se-is monitored. We developed a nontoxic hybrid composite-based sensor consisting of graphite powder (conductive filler), clay (viscosity control filler) and linseed oil (the matrix). Upon exposure to oxygen, the insulating linseed oil is oxidized, leading to polymerization and shrinkage of the matrix and hence to an increase in the concentration of the electrically conductive graphite powder up to percolation, which serves as an indicator of food spoilage. In the developed sensor, the exposure time to oxygen (days to weeks) is obtained by measuring the electrical conductivity though the sensor. The sensor functionality could be tuned by changing the oil viscosity, the aspect ratio of the conductive filler, and/or the concentration of the clay, thereby adapting the sensor to monitoring the quality of food products with different sensitivities to oxygen exposure time (e.g., fish vs grain).

Synergetic Improvement of Stability and Conductivity of Hybrid Composites formed by PEDOT:PSS and SnO Nanoparticles.

In this work, layered hybrid composites formed by tin oxide (SnO) nanoparticles synthesized by hydrolysis and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) have been analyzed. Prior to the composite study, both SnO and PEDOT:PSS counterparts were characterized by diverse techniques, such as X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), photoluminescence (PL), atomic force microscopy (AFM), optical absorption and Hall effect measurements. Special attention was given to the study of the stability of the polymer under laser illumination, as well as the analysis of the SnO to SnO2 oxidation assisted by laser irradiation, for which different laser sources and neutral filters were employed. Synergetic effects were observed in the hybrid composite, as the addition of SnO nanoparticles improves the stability and electrical conductivity of the polymer, while the polymeric matrix in which the nanoparticles are embedded hinders formation of SnO2. Finally, the Si passivation behavior of the hybrid composites was studied.

Comparative Evaluation of Mechanical and Microleakage Properties of Cention-N, Composite, and Glass Ionomer Cement Restorative Materials.

AIM: The longevity of restorative materials depends on the resistance to masticatory forces. The present study was undertaken to evaluate the mechanical and microleakage properties of Cention-N with glass ionomer cement (GIC) and composite restorative materials. MATERIALS AND METHODS: A total of 45 specimen blocks were prepared with 15 samples of each type of restorative material, namely Cention-N, GIC, and hybrid composite. Samples were subjected to load at crosshead speed of 0.75 ± 0.25 mm/min till the fracture of sample. Class V cavities were prepared on the buccal surface of orthodontically extracted premolars followed by restoration of each test material. All the surfaces of the tooth were coated with clear nail varnish except 1 mm around the margins of the restorations. These samples were immersed in 0.5% basic fuchsine dye and longitudinally sectioned and observed under stereomicroscope to check microleakage. The obtained data were statistically evaluated. RESULTS: We found the highest mean compressive and flexural strength for hybrid composite followed by Cention-N and least for GIC which is statistically significant (p < 0.001). CONCLUSION: Mean microleakage was least for Cention-N. Cention-N is a newer restorative material having higher mechanical properties with lesser microleakage. CLINICAL SIGNIFICANCE: Cention-N is a newer restorative material having promising properties. This material can be used as an alternative restorative material.

Preparation of a glassy carbon electrode modified with reduced graphene oxide and overoxidized electropolymerized polypyrrole, and its application to the determination of dopamine in the presence of ascorbic acid and uric acid.

This paper presents a method for the preparation of a graphene-based hybrid composite film by electrodeposition of reduced graphene oxide and overoxidized electropolymerized polypyrrole onto a glassy carbon electrode (GCE) using cyclic voltammetry. The morphology of the hybrid composite film was characterized by scanning electron microscopy. The electrochemical activity of the modified GCE was studied by cyclic voltammetry using the negatively charged redox probe Fe(CN)63- and the positively charged redox probe Ru(NH3)63+. The modified GCE displays excellent electrocatalytic activity for dopamine (DA) and uric acid (UA), but electrostatically repulses ascorbate anion under physiological pH conditions. The voltammetric response to DA is linear in the 2.0 µM to 160 µM concentration range even in the presence of 1.0 mM ascorbic acid and 0.1 mM of UA. The detection limit is 0.5 µM. The amperometric response to DA (best measured at 0.22 V vs. Ag/AgCl) extends from 0.4 µM to 517 µM and has a 0.2 µM detection limit. Graphical abstract Schematic presentation of the fabrication of a glassy carbon electrode modified with reduced graphene oxide and overoxidized electropolymerized polypyrrole, and its application to the determination of dopamine in the presence of ascorbic acid and uric acid.

Efficient and Selective Methane Borylation Through Pore Size Tuning of Hybrid Porous Organic-Polymer-Based Iridium Catalysts.

As a new energy source that could replace petroleum, the global reserves of methane hydrate (combustible ice) are estimated to be approximately 20 000 trillion cubic meters. A large amount of methane hydrate has been found under the seabed, but the transportation and storage of methane gas far from coastlines are technically unfeasible and expensive. The direct conversion of methane into value-added chemicals and liquid fuels is highly desirable but remains challenging. Herein, we prepare a series of iridium complexes based on porous polycarbazoles with high specific areas and good thermochemical stabilities. Through structure tuning we optimized their catalytic activities for the selective monoborylation of methane. One of these catalysts (CAL-3-Ir) can produce methyl boronic acid pinacol ester (CH3 Bpin) in 29 % yield in 9 h with a turnover frequency (TOF) of approximately 14 h-1 . Because its pore sizes favor monoborylated products, it has a high chemoselectivity for monoborylation (CH3 Bpin:CH2 (Bpin)2 =16:1).

Electrospun nanofibers hybrid composites membranes for highly efficient antibacterial activity.

Safety of drinking-water is an urgent for human health. It is critical to promote the cheap technologies for water purification to guarantee the free-pathogens-drinking water. The present study has been investigated the antibacterial activity of polyacrylonitrile (PAN) nanofibers membranes which decorated by Ag, CuO or ZnO nanoparticles as bactericides. The hybrid nanofiber composites were fabricated by electrospinning technique and the obtained membranes were characterized using SEM, EDX and FTIR. Their antibacterial activity was evaluated against E. coli and S. aureus. The data was revealed that the functionalization was successfully obtained by the incorporation of nanoparticles as an additive into the polymer solution which associated many superior properties. Continuous PAN membrane fibers with average diameters from 170 to 250 nm without any beads of plain and its hybrid membrane composites were obtained. The antimicrobial activity was estimated using both disk diffusion tests and growth kinetic models. The antibacterial activity was improved as the concentrations of nanoparticles enhanced. This study provided the real solution for production and inactivation of bacteria which related to the impregnated the PAN nanofibers membrane with Ag, CuO or ZnO NPs. The results have significant implications for finding a safe and an inexpensive path to solve the problems of drinking water, especially in the developing countries.

Evaluation of the Flexural Strength of Submicron Hybrid Composite using Different Fabrication Methods: An in vitro Study.

AIM: The aim of this study is to perform three-point bend test on submicron hybrid composite fabricated with direct and indirect veneer technique. MATERIALS AND METHODS: A total of 20 maxillary anterior teeth were selected, and labial reduction of 0.5 to 0.75 mm with a chamfered finish line for veneer preparation was done. Teeth were divided into two groups depending on fabrication technique being used: group I-veneers fabricated with light and group II-veneers fabricated with light and heat (PHOTOPOL). Specimens were tested under universal testing machine (UTM) where load was applied at a crosshead speed of 1 mm/min with a pointer of 1 mm diameter. Data were statistically analyzed. RESULTS: The results showed highly significant difference between the two groups with the mean value of group I (246.7 ± 2.285 N) and group II (531.1 ± 4.411 N). CONCLUSION: The curing mechanism involving light and heat increases the fracture resistance of the veneers. CLINICAL SIGNIFICANCE: Within the limitations of this study, the results led to the conclusion that the association of common composites with a simple postcure heat treatment may be an alternative for current indirect composite systems, although more studies are needed to assess other properties of the composites for this application.