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Developing efficient carbon dioxide (CO2) capture and conversion methods is vital for climate change mitigation. Cycloaddition of CO2 with epoxides to form cyclic carbonates is a promising utilization method. In this study, a deep eutectic solvent‐modified dendritic fibrous nano‐silica (DES@DFNS) catalyst was synthesized by functionalizing DFNS with DES. This catalyst was used for the cycloaddition of CO2 with styrene oxide to produce styrene carbonate. The material's morphology and properties were characterized using various analytical techniques, revealing a high surface area, good porosity, and significant concentrations of Lewis acidic and basic sites. Rietveld refinement analysis provided insights into its phase composition, crystallite size, microstrain, stress, and other microstructural properties. Despite a lower surface area, DES@DFNS demonstrated superior catalytic activity. The interaction between DES and DFNS showed that DES was physically adsorbed onto the DFNS surface, contributing to its enhanced performance. Factors such as smaller crystallite size, higher microstrain, increased dislocation density, and improved elastic properties provided more active sites and greater mechanical stability, boosting overall efficiency and durability. The DES@DFNS catalyst achieved 99% conversion of styrene oxide with 96% selectivity and 95% yield of styrene carbonate at 120 °C for 10 h under solvent‐free, atmospheric conditions. The synergistic effect of Lewis acidic and basic sites on DES@DFNS supported catalytic activity under moderate conditions. Additionally, the catalyst demonstrated reusability, maintaining performance for up to six cycles without significant loss of activity, making it a promising candidate for sustainable CO2 fixation and valorization processes. [ABSTRACT FROM AUTHOR]

MXenes, a class of two-dimensional (2D) materials, have gathered significant attention as excellent electrode materials for various energy applications owing to their remarkable properties such as superior metallic conductivity, abundant surface functionality, high electrical conductivity, hydrophilicity, abundance of surface active sites, enormous cycle life, and ordered lamellar structure. In this study, we present the heterostructured growth of bimetallic Co-NiSe2 on MXene via a simple hydrothermal method. The resulting hybrid structure of Co-NiSe2 exhibits nanorod-like morphology wrapped around MXene sheets. When evaluated as an electrode material for supercapacitors, the Co-NiSe2/MXene composite demonstrates enhanced feasibility, displaying relatively high specific surface area and electrical conductivity, thus exhibiting excellent electrochemical performance. Specifically, the Co-NiSe2/MXene composite exhibits a high specific capacitance of 1394.8 F·g–1 at a current density of 1 A·g–1. Furthermore, the synergetic hybrid material can deliver a high energy density of 20 Wh·kg–1 at a power density of 684 W·kg–1. Importantly, the Co-NiSe2/MXene material exhibits good rate performance and cycle stability, showcasing its potential for advanced energy storage applications. [ABSTRACT FROM AUTHOR]

In this study, we presented hollow bimetallic mixed oxides of molybdenum and nickel, prepared through a facile polymer-assisted solution process. Our focus was on addressing the influence of polymer concentration on the formation of hollow nanoparticles (HNPs) of the bimetallic mixed oxides, a critical aspect explored through XRD, Raman, and TEM analyses. Raman study indicated that as the PAA concentration increases, the oxygen vacancies become more dominant with a decrease in the O/Mo ratio. The formation process of the hollow structure in the MoO3/NiMoO4 nanostructure was confirmed using FESEM and TEM. The influence of oxygen vacancies over the surface of the mixed oxides and their concentration was examined by XPS analysis. The resulting MoO3/NiMoO4 HNPs serve as catalysts for the oxygen evolution reaction (OER), and their performance was systematically investigated using ECSA, EIS, CV, and LSV analyses. The superior electrochemical performance of the optimized mixed oxide composite is attributed to the increased number of oxygen vacancies, electrical conductivity, and a reduced Tafel slope. Notably, the best composite exhibits a 3-fold increase in electrochemical surface area and a lower overpotential. Specifically, the reduction in the Tafel slope from 142.2 to 97.5 mV dec−1 and the overpotential from 402 to 330 mV for HNPs prepared with PAA 0.10 g/10 mL and PAA 0.15 g/10 mL, respectively, underscores the efficacy of the developed catalyst. DFT calculations of the OER were found to be uphill in energy which makes the *O to *OOH step the PDS for defective metal oxide with a ΔG of 3.00 eV. This research contributes valuable insights that open new avenues for the application of molybdenum oxides and their derivatives in water-splitting processes. The findings not only address the challenges in OER kinetics but also hold promise for advancing the field of green hydrogen production through enhanced electrocatalytic materials. [ABSTRACT FROM AUTHOR]

Different wounds take a while to heal, and the process is frequently accompanied by bacterial infection and scar formation. This study aimed to fabricate polyurethane (PU) fibers through electrospinning, utilizing a mixture of THF and DMF solvents in a 90:10 ratio. Subsequently, these fibers were coated with different concentrations of hyaluronic acid (HA) and silver (Ag) nanoparticles (NPs) using the hydrothermal treatment to create biocompatible and antibacterial scaffolds applicable to wound management. Pristine samples served as a basis for comparison. Following high-temperature usage during the hydrothermal coating, the Field emission scanning electron microscopy (FE-SEM) results showed defect-free morphology. However, the fibers' diameter significantly increased by layer of HA. In particular, the diameter of the PU fibers was 1.87 ± 1.1 µm, whereas the fibers with the maximum amount of HA (0.5%) had an enlargement of 4.43 ± 1.4 µm in fiber diameter. The Fourier transform infrared (FTIR) spectroscopy demonstrated the presence of distinctive functional groups, supporting the hypothesis that HA and Ag NPs were efficaciously coated on PU fibers. Moreover, HA-coated fibers improved hydrophilicity, mechanical strength, thermal stability, degradability, and biomineralization. Notably, the Ag-coated scaffolds exhibited antibacterial activity against E. coli and S. aureus. The MTT assay, DAPI staining, and FE-SEM results after culturing HEK 293T cells have demonstrated the biocompatibility of the nanocomposite fibers. In other words, the developed HA and Ag NPs coated PU fibers by hydrothermal technique would be a futuristic method for promoting tissue healing and imparting antibacterial ability in curing skin wounds. [ABSTRACT FROM AUTHOR]

Numerous strategies exist to design a suitable bone graft made from polyurethane (PU) nanofibers. However, using PU nanofibers is impractical owing to their hydrophobicity. This work transforms the hydrophobicity of PU nanofibers using β‐cyclodextrin (β‐CD) and zinc oxide (ZnO) nanoparticles (NPs). Transmission and scanning electron microscopy (SEM) indicated the size of ~100 to 200 nm for ZnO NPs, and these NPs could finely harmonize inside nanofibers. The phenolphthalein absorbance test confirmed the inclusion of ZnO and β‐CD. Fourier transform infrared, X‐ray diffraction, and photoelectron spectroscopy showed that synthesized composites have intermolecular hydrogen interactions between the PU, β‐CD, and ZnO NPs. These embellishments improved the hydrophilicity from a contact angle of 60.2 ± 0.2° to 0°. The tensile strength of modified fibers increased from 2.16 ± 0.14 to 6.65 ± 6.0 MPa. The incorporation of ZnO NPs caused the mineralization of the nanofibers and the maximum number of hydroxyapatite NPs in the composite, which had the highest concentration of ZnO NPs. These nanofiber mats boosted the proliferation of Human Embryonic Kidney 293 T cells till 6 days of culture for the nanofiber with 5% β‐CD and 75 mg ZnO NPs combination. Cell fixation studies indicated the successful attachment of cells onto nanofibers. Consequently, our multifunctional scaffolds could be osteoproductive and osteoinductive biomaterials for future bone tissue engineering. [ABSTRACT FROM AUTHOR]

The anthropogenic carbon dioxide (CO2) fixation and various engineering strategies are gaining very significant attention because of the expansion of the net‐zero carbon environment in the atmosphere. Herein, we designed a sodium aluminate@γ‐alumina (NaAlO2@γ‐Al2O3) catalyst by a simple and facile precipitation and impregnation tactics. A series of different weight percentage NaAlO2@γ‐Al2O3 materials were successfully synthesized and well characterized by using advanced analytical and spectroscopic techniques such as TGA, XRD, FE‐SEM, TEM/HR‐TEM, FT‐IR, Raman, TPD, and XPS analysis. The NaAlO2@γ‐Al2O3 catalyst was employed as a competent catalyst for the CO2 fixation under atmospheric pressure reaction conditions. The catalytic activity results evidently revealed that the cycloaddition reaction successfully achieved 94% styrene oxide conversion and 93% selectivity, along with an 87% yield of the styrene carbonate at 120 °C for 6 h. Furthermore, we comprehensively examined the effect of different reaction parameters such as the effect of sodium aluminate amount, co‐catalyst amount, temperature, and time for CO2 fixation reaction. Additionally, different terminal and internal epoxides were tested under optimized reaction conditions and achieved moderate to excellent yield of the desired cyclic carbonate products. Interestingly, a plausible reaction mechanism was proposed for the styrene carbonate synthesis using NaAlO2@γ‐Al2O3 catalyst surface with the support of characterization and experimental results. Remarkably, the NaAlO2@γ‐Al2O3 catalyst could be easily recoverable and successfully recyclable up to six consecutive cycles without declining its initial catalytic activity along with stable structural and physicochemical properties. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) has received very little exploration on its importance in the realm of battery‐type energy storage technologies. They are abundantly present in seawater, and if successfully extracted and utilized in energy storage systems, it could lead to the long‐term advancement of human civilization. Here, we fabricated an all‐solid‐state supercapacitor (ASSSC) using tellurium nanotubes decorated cobalt magnesium telluride microtubes (Te NTs@CoMgTe MTs) clad on nickel foam (NF). Owing to the unique mixed phase hierarchical structure, Te NTs@CoMgTe MTs showcases some advancement in energy storage performance. When tested in a three‐electrode system, multiphasic hybrid of elemental Te and metal tellurides, Te NTs@CoMgTe MTs outperforms the monometallic telluride owing to the strong synergistic interaction effect triggered from conductive three components and delivers a long‐life span performance up to 15,000 cycles. The fabricated Te NT@CoMgTe MT//AC solid‐state device exhibits a maximum areal capacity of 59.2 μAh cm−2 (56.3 mAh g−1) at a current density of 6 mA cm−2 with a maximum energy density of 42.2 Wh kg−1 (46.5 μWh cm−2) at a power density of 6857.1 W kg−1 (7574.6 μW cm−2). The performance of the device is rigid even at different bending angles (0 to 180°) which validates the extensibility of the process for future applications. [ABSTRACT FROM AUTHOR]

The selective fixation of CO2 and epoxides into cyclic carbonates offers an atom-economical approach towards promising utilization of anthropogenic CO2 gas. This work demonstrates the development of recyclable organic–inorganic hybrid TBAI@CuO catalyst containing quaternary ammonium (TBAI) salt as active organic groups and CuO flowers as the inorganic component. Initially, CuO flowers was synthesized using a simple oxidation-precipitation method followed by immobilization of TBAI groups using impregnation method. The impregnated TBAI groups functioned as the active basic centers, whereas CuO flowers with effective surface area provided heterogeneity, Lewis acidic sites, facilitated better dispersion and strong interaction of TBAI. Resultantly, hybrid TBAI@CuO catalyst consisted of dual-active sites which played a decisive role in manipulating catalytic activity without requirement of a co-catalyst. With styrene oxide and CO2 as model substrates, the present catalyst system delivered 95% conversion and 97% selectivity towards styrene carbonate under solvent-free and milder reaction conditions when compared to other single metal oxide catalysts. The homogeneously dispersed TBAI groups in strong interaction with CuO flowers provided simultaneous access to both Lewis acidic as well as basic sites and hence resulted in superior catalytic activity. Meanwhile, hybrid TBAI@CuO catalyst showed catalytic adequacy for various terminal and internal epoxides. This catalytic system also presented good reusability without prominent loss in activity and no leaching of active TBAI groups. Based on characterization results, a plausible reaction mechanism was predicted to support the cycloaddition reaction with hybrid TBAI@CuO catalyst. It was proposed that inorganic Lewis acidic CuO activated the epoxide whereas the immobilized TBAI groups activated the inert CO2 molecule and stabilized the epoxide after ring opening. Therefore, the CuO flowers acting in concert with the immobilized TBAI groups showed exceptional acid–base cooperativity and provided high selectivity towards cyclic carbonates. The hybrid TBAI@CuO catalyst in this effort bridges the gap between homogeneous and heterogeneous catalysis for sustainable transformation of CO2 and epoxides to cyclic carbonates under solvent-free and comparatively mild reaction conditions [ABSTRACT FROM AUTHOR]

Exploring the utilization of earth-abundant metals for essential organic transformations is highly fascinating from an industrial viewpoint. In this present study, a simple and energy efficient precipitation protocol was employed for the synthesis of hierarchical MgO microspheres that were efficiently used as catalysts in the Claisen–Schmidt condensation reaction. The hierarchical MgO microsphere catalyst was prepared via a precipitation process using Na2CO3 as a precipitating agent under green reaction conditions. The inherent properties of the synthesized MgO hydroxide and MgO microspheres were well characterized using advanced analytical and spectroscopic techniques, such as TGA, XRD, FE-SEM, EDAX, TEM/HR-TEM, FT-IR, XPS, NH3 and CO2-TPD analyses. The synthesized MgO material successfully achieved excellent inherent properties, such as high thermal stability, good crystallinity, microsphere morphology, large specific surface area, and uniformly dispersed active sites on the material surface. Using the MgO catalyst, various reaction parameters, such as the effect of catalyst dosage, temperature, time, and solvents, were examined. As a result, chalcone was obtained as a product with 100% conversion and 90% yield in the presence of green solvent ethanol under reflux conditions at 80 °C for 20 h with 20 wt% catalyst amount. The catalytic activity was truly reliant on the inherent properties of hierarchical MgO microspheres. The competent MgO microsphere catalyst showed excellent catalytic activity for aldehyde and acetophenone molecules functionalized with electron-withdrawing groups and achieved respective chalcone products with excellent yields (84–91%) under optimized reaction conditions. The prominent structural and physicochemical properties facilitated catalytic activity in the Claisen–Schmidt condensation reaction under temperate reaction conditions. Remarkably, the efficient hierarchical MgO microsphere catalyst showed excellent recyclability up to 8 consecutive cycles with insignificant loss of its initial catalytic activity under optimized reaction conditions. The characteristic results of the spent MgO catalyst showed supportive evidence for stable structural and physicochemical properties. [ABSTRACT FROM AUTHOR]

Utilization of anthropogenic CO2 for the synthesis of valuable heterocyclic compounds is a very significant strategy to alleviate environmental issues. Herein, a hollow CeO2 nanosphere (HNS–CeO2) material made using solvothermal-method-assisted synthesis was employed as an efficient catalyst for the selective benzimidazole synthesis under neat and temperate reaction conditions. We examined the controlled reaction conditions for the design of the HNS–CeO2 material through the study of various reaction parameters. Very interestingly, the HNS–CeO2 material exhibited different surface morphological disparities due to the effect of various reaction parameters that were examined comprehensively using field emission scanning electron microscopy analysis. The HNS–CeO2 material was systematically well characterized using various analytical and spectroscopic techniques. The competent catalyst of HNS–CeO2 showed superior catalytic activity (100% conversion, 96% selectivity, and yield) under mild reaction conditions, and these conditions are successfully identified by studying the effect of various reaction parameters. Remarkably, the inherent properties of the HNS–CeO2 catalyst boosted the synergistic effect with the model reagents of o-phenylenediamine, carbon dioxide, dimethylamine borane (DMAB), and base. Moreover, different functional groups substituted benzimidazole compounds are successfully synthesized in good to excellent yields under optimized reaction conditions. The effective contributions of DMAB, base, Lewis acidic, and Lewis basic sites were successfully revealed by proposing a tentative benzimidazole reaction mechanism. Notably, the examined 15 successive recycles with stable catalytic activity performance demonstrated the stable catalytic activity and structural and physicochemical properties of the HNS–CeO2 catalyst. [ABSTRACT FROM AUTHOR]

The hydrophobicity of polyurethane fibers is undesired for tissue engineering. In this work, fibers are fabricated by electrospinning and coated with silk fibroin (SF) for biocompatibility and biologically synthesized silver (Ag) nanoparticles (NPs) for antibacterial activity. The scanning electron microscopy reveals the undistorted morphology and the presence of NPs on fibers. The Fourier transform infrared and thermogravimetric analysis show the successful incorporation of SF and Ag NPs. The water contact angle drops from 101.26±0.2° in pristine to 3.1±0.3° in the hydrothermally treated fibers. The moisture regain from 1.87±0.3% to 6.7±0.4% is observed after 24 h. The mineralization shows the hydroxyapatite NPs in all composites. The large zone of inhibition is observed in the composite, with the Ag NPs equal to 11.5±0.04 mm for Staphylococcus aureus and 18.91±0.02 mm for Escherichia coli. The increased proliferation of HEK 293T cells for 6 days of culture on composite scaffolds compared to the pristine scaffolds is achieved. The cell attachment examinations show successful attachment of cells on fibers and nuclear staining analysis shows the highest proliferation in scaffolds with an intermediate concentration of Ag NPs (10%). This strategy presents a novel improvisation for as‐spun PU fibers that can fabricate wound‐healing biomaterials for tissue engineering. [ABSTRACT FROM AUTHOR]

Heterocyclic compounds have a wide range of applications, and Pictet–Spengler reaction is effectual in the synthesis of heterocyclic compounds such as quinoline and isoquinoline. The present work describes an effective Pictet–Spengler-type protocol for the selective synthesis of quinoxaline derivatives from substituted pyrroles and diverse aromatic aldehydes over tailored SnO2 nanoparticles anchored multi-walled carbon nanotubes (SnO2@MWCNTs) nano-catalyst under greener reaction condition. An elementary reaction process (chemical synthesis) of oxidation of MWCNTs followed by uniform dispersion of SnO2 nanoparticles is used to synthesize the SnO2@MWCNTs catalyst. The SnO2@MWCNTs catalyst was then characterized by using modern spectroscopic and analytical techniques. The activity of catalyst was investigated toward the formation of selective quinoxaline. The reaction progressed with 100% conversion and 93–80% yield for the desired product at ambient operating conditions in just 2.30–3.30 h of reaction time. The effect of different parameters such as reaction temperature, time, and loading of SnO2 on MWCNTs, SnO2@MWCNTs catalyst loading were also investigated and discussed in detail. The protocol displayed high tolerance to different functionalities with respect to different substituted aromatic aldehydes to form quinoxaline derivatives in efficient way and gave excellent yield. Plausible reaction mechanistic pathway for the selective formation of quinoxaline over SnO2@MWCNTs is also proposed. It is believed that high dispersion of SnO2 over MWCNTs provided sufficient Lewis acidic sites for the reaction to selectively obtain the final product. Additionally, recyclability of SnO2@MWCNTs catalyst was also studied which demonstrated that the catalyst could be efficiently reused for six successive cycles without significant loss in its activity. The present work provides greener approach for synthesis of quinoxaline derivative preparation with high selectivity (free from oxidized quinoxaline as a side product) and efficient yield. [ABSTRACT FROM AUTHOR]

In order to meet the current energy storage demands, the rational design of novel nanostructured materials is crucial for the improvement of electrochemical storage and conversion performance. Nanostructured materials have shown promising results in various energy harvesting systems, owing to their multifunctional properties such as a large active surface area, mechanical strength, catalytic ability, excellent ion diffusion, and electronic conductivity. To date, the library of nanostructured materials consists of diverse compositions ranging from oxides, dichalcogenides, carbides to graphene-based and lithium alloys with various morphologies such as zero-dimensional (0D), 1D, 2D and 3D nanomaterials. In particular, nanosponges have exhibited unusual three-dimensional architecture that provides rich surface defects and excellent structural stability resulting in improved catalytic activity. Additionally, the large conducting surface, electronic conductivity and pronounced crystalline phase stability of nanosponges have been utilized to improve the electrode performance drastically. Moreover, the unique sponge-like metallic porous network not only reduces the overall weight of the device but also decreases the consumption of metal usage. In this context, this review particularly highlights the recent progress in the synthesis and properties of noble metals and other metal-based sulphide, oxide, hydroxide and phosphide nanosponges, and their application in electrochemical storage and conversion devices. [ABSTRACT FROM AUTHOR]

Summary: Rational designing of advanced electrocatalysts for oxygen evolution reaction (OER) for energy sustainability is challenging. In this perspective, the fabrication of an efficient ternary hybrid composite electrocatalyst consisting of carbon‐based materials and earth‐abundant metal oxides can be thought as a better choice for large‐scale applications. Hybrid of MoO3 and NiO with carbon material would possibly improve stability and conductivity which can assist in improving OER performance. In this regard, we report the development of MoO3/NiO/activated carbon (MoNiAC) ternary hybrid catalyst by a facile, one‐step solution combustion synthesis (SCS) method. The physiochemical properties of the synthesized catalyst were evaluated by advanced analytical and spectroscopic techniques. The MoNiAC ternary hybrid catalyst exhibited a lower over‐potential (279 mV) (without iR compensation) to attain the current density of 10 mA/cm2, and small Tafel slope of 89 mV/dec was accompanied. The superior activity could be ascribed to the synergism between MoO3, NiO, and AC. Furthermore, the stability graph of the hybrid demonstrated appreciable durability of catalyst for upto 8.33 h. The characterization of after stability catalyst suggested no major disturbance in the morphology as well as element distribution signifying the high durability of the hybrid catalyst in terms of activity as well as morphology. The remarkable features such as appreciable OER activity, promising kinetics, and robustness ameliorated the performance of MoNiAC hybrid as an electrocatalyst for OER. [ABSTRACT FROM AUTHOR]

The involvement of CO2 as a renewable and abundant feedstock toward a carbon balanced future has led to production of several value-added products. The primary focus in the current effort is to assess fixation of CO2 and epoxides into cyclic carbonates by employing state-of-the-art metal complexes as promising catalytic systems. Our attention is restricted to Earth-abundant metals such as aluminum, cobalt, iron, zinc and few transition metals in association with different ligand skeletons used for the structural construction of the respective complexes. This review sequentially categorizes these complexes and provides a panoramic overview of their selective catalytic activities and mechanistic understandings based on experimental and theoretical evidences. [ABSTRACT FROM AUTHOR]

An eco-friendly green method for a one-step synthesis of palladium nanoparticles and their synthetic utility are reported. Phytochemicals like amines, alcohols, and phenols present in the Areca Nut Husk extract facilitate the reduction of Pd(II) to Pd(0). The phytochemicals serve as stabilising agents and ligands for palladium reduction and the need for an external ligand is avoided. The Field Emission Scanning Electron Microscopy and Transmission Electron Microscopy of newly synthesized palladium nanoparticles revealed a spherical morphology. The catalytic activity of the nanoparticles was tested for 1,2-difunctionalization of ynamides, Heck coupling, denitrogenative coupling of phenylhydrazine and C–H arylation of indole. Moreover, catalyst recyclability, control experiments, mechanistic elucidation, and gram-scale synthesis are elaborated. [ABSTRACT FROM AUTHOR]

In this work, a uniquely designed imidazolium-based dicationic ionic liquid (IL) was synthesized as a greener template and applied for the synthesis of ZSM-5 zeolite as a heterogeneous catalyst for the dehydration of fructose to 5-hydroxymethylfurfural (HMF). Characterization results confirmed that due to the presence of dicationic IL as template, effective interactions and structural alterations occurred during the construction of zeolitic framework wherein the vertices of ZSM-5 consisting of Al or Si and O elements were assumed to be bonded between the vertices of dicationic IL-assisted zeolite ZSM-5 catalyst. This resulted in superior structural advantages such as highly crystalline nature and stability as well as variation in mesopores when compared to commercial ZSM-5. Additionally, various reaction variables were investigated wherein synthesized dicationic IL-assisted ZSM-5 zeolite catalyst in the presence of [BMIm][Cl] as solvent demonstrated 95% conversion of fructose and 67.2% yield of HMF at 110°C within 90 min. The altered surface area and porous nature of synthesized ZSM-5 due to the presence of dicationic IL as template was responsible for the enhanced catalytic performance under mild reaction conditions. Most significantly, being a solid catalyst, the newly developed dicationic IL-assisted zeolite ZSM-5 catalyst showed recyclability for four recycles. [ABSTRACT FROM AUTHOR]

There is an extensive possibility of improving characteristics of fibers used in hard tissue engineering, being hydrophobic and less osteoconductive, resulting in the dynamic growth of new tissues. The current work focuses on the fabrication of nanofibers incorporated with titanium dioxide (TiO2) ''as osteoconductive'' and silver (Ag) ''as self‐healing'' nanoparticles (NPs). The incorporation of AgNO3 by in situ method not only helped to impart the antibacterial activity but also changed the contact angle from 81 ± 03° in the case of pristine nanofibers to 74 ± 03°, 61 ± 03°, 50 ± 08°, and 39 ± 1.1°, in the composite scaffolds containing 0.01, 0.03, 0.05, and 0.07 M of Ag salts. The incubation in simulated body fluid at 37°C to induce mineralization on nanofiber scaffolds indicated Ca and P crystals' formation. The antibacterial activity showed significantly more toxicity toward E. coli (8.3 ± 0.9 mm) than S. aureus (1.2 ± 0.1 mm). Biocompatibility studies using MTT assay on the pre‐osteoblasts showed that both TiO2 and Ag NPs present in the nanofibers are non‐toxic to the bone‐like cells. However, results show that a higher concentration of Ag NPs (i.e., 0.07 M) is toxic to cells growing. Finally, all the results suggest that the nanofiber scaffolds have considerable scope for future bone tissue engineering materials. [ABSTRACT FROM AUTHOR]

Heterocyclic chemistry has fascinated the researchers owing to its wide range of applications in various chemical fields. With this perspective, herein we present an environmentally benign procedure for the synthesis of pyrazole and its derivatives through multicomponent reaction by using SPVA as a heterogeneous acid catalyst. The synthesis protocol of SPVA catalyst includes functionalization of polyvinyl alcohol by sulfonic acid groups. The synthesized SPVA catalyst was then subjected to several characterization techniques to confirm its formation and study its physicochemical properties. The SPVA catalyst was then tested for its activity toward a multicomponent reaction of aromatic aldehyde, malononitrile and phenyl hydrazine. The SPVA catalyst with sufficient acidic sites displayed appreciable catalytic performance yielding 89% of the desired pyrazole product under ambient reaction conditions. The SPVA catalyst showed recyclability up to the sixth cycle without considerable loss in its activity. Furthermore, we made an effort to demonstrate the plausible mechanistic pathway for the SPVA-catalyzed pyrazole synthesis reaction. Interestingly, the present synthetic approach could effectively produce pyrazole products with high yields in the absence of base and solvent and in short reaction time making it a green and sustainable process. [ABSTRACT FROM AUTHOR]

The present work describes synthesis of a series of benzimidazoles, benzoxazoles and benzothiazoles through the cyclization of 1, 2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, aliphatic and heteroaryl aldehydes. The present synthetic protocol is very much efficient in presence of 5 mol % fluorophosphoric acid as a catalyst in ethanol solvent at room temperature. Shorter reaction time, simple work-up technique, high yields and easy availability are specific compensations of the present synthetic approach. [ABSTRACT FROM AUTHOR]

A regioselective C2 arylation of indoles, benzothiophene and benzofuran without directing group has been accomplished using economically cheap Pd NPs and NHC-Pd@MNPs catalyst. The reusable catalyst is efficiently employed to access C2 arylated heterocycles in good to excellent yield. The reusability of the catalyst is studied up to five cycles and a gram-scale synthesis has been achieved. The reaction mechanism is well supported by control experiments and literature precedents. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of cinnamaldehyde to hydrocinnamaldehyde is captivating due to its industrial relevance. Herein, a two-step synthesis method was adopted to develop oxygen vacancies in Pd@ZrO2 catalysts. The oxygen vacancies were developed in Pd@ZrO2 catalysts during impregnation of Pd which was confirmed by XPS and HR-TEM analyses. The characterization results revealed that there was a synergistic role of oxygen vacancies and nano-sized active Pd metals in Pd@ZrO2 catalysts that assisted in achieving selectivity for hydrocinnamaldehyde which has been discussed in this study. We also studied the effects of different reaction parameters which revealed that 4 wt% Pd loading in a Pd@ZrO2 catalyst provided enough active sites for complete conversion of CAL. Additionally, 100 °C temperature and 10 bar H2 pressure provided enough energy for effective collisions and activation of reactants and catalysts to form the desired product in a reaction time of 9 h. Therefore, a defect-rich 4-Pd@ZrO2 catalyst demonstrated complete CAL conversion with 86% yield towards HCAL which is the best result amongst various Pd@ZrO2 catalysts with different Pd loading investigated for the hydrogenation of cinnamaldehyde. Moreover, a plausible mechanism was proposed to support the chemoselective hydrogenation of cinnamaldehyde over a 4-Pd@ZrO2 catalyst. Along with high catalytic performance, the 4-Pd@ZrO2 catalyst also showed impressive recyclability performance for up to six recycles. Thus, the oxygen-vacancy-rich Pd@ZrO2 can be considered as an efficient catalyst for the chemoselective hydrogenation of cinnamaldehyde. [ABSTRACT FROM AUTHOR]

The present work describes synthesis of a series of benzimidazoles, benzoxazoles and benzothiazoles through the cyclization of 1, 2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, aliphatic and heteroaryl aldehydes. The present synthetic protocol is very much efficient in presence of 5 mol % fluorophosphoric acid as a catalyst in ethanol solvent at room temperature. Shorter reaction time, simple work-up technique, high yields and easy availability are specific compensations of the present synthetic approach. [ABSTRACT FROM AUTHOR]

A domino protocol involving aldehydes, isocyanides and 2-pyridylacetonitrile in the presence of [bmim]Cl as a promoter and solvent for the synthesis of 3-alkylamino-2-alkyl/arylindolizine-1-carbonitriles is described. A wide range of alkyl, aryl and hetero-aryl aldehydes reacted with 2-pyridylacetonitrile and isocyanides, leading to indolizine derivatives with high selectivity, high atom economy, and good to excellent yields. This straight-forward and highly efficient method allows the synthesis of bis-indolizine-1-carbonitrile derivatives. [ABSTRACT FROM AUTHOR]

The present study describes the hydrogen production as a future energy source via hydrolysis of NaBH4 catalyzed by urchin-like CuCo2O4 spinel catalyst prepared by urea-assisted hydrothermal synthesis method. The as-synthesized copper–cobalt double hydroxide precursor and the resultant CuCo2O4 spinel were characterized by using various analytical, spectroscopic and microscopic techniques in order to understand their physiochemical and morphological aspects. The detail characterization results confirmed the successful formation of CuCo2O4 spinel phase with urchin-like morphology. The CuCo2O4 spinel catalyst was then tested for its application in hydrogen generation from NaBH4 hydrolysis by performing the reaction using 10 wt% of CuCo2O4 spinel catalyst and 0.5 g NaBH4 at room temperature. The CuCo2O4 spinel catalyst with tailored architecture displayed high catalytic activity with H2 generation rate of 1370 mL min−1 g−1 (1438 mL in 21 min). Major factors affecting the hydrolysis of NaBH4 reaction such as catalyst loading, NaOH concentration and temperature variation was also studied and discussed in detail. Correspondingly, the low activation energy of 22 kJ mol−1 was obtained from the Arrhenius plot and kinetic studies revealed that the hydrolysis of NaBH4 followed first order kinetics. Further, recyclability study of CuCo2O4 spinel catalyst was also performed which displayed good catalytic activity and stability even after five successive recycles. Characterization data of reused catalyst revealed that physiochemical properties of fresh CuCo2O4 spinel catalyst were well-preserved in the reused catalyst as well. Therefore, nanostructured CuCo2O4 spinel can be demonstrated as one of the most efficient, cost effective bimetallic spinel catalyst so far for application in the hydrogen generation. [ABSTRACT FROM AUTHOR]

The growing pursuit of the viable application of γ-butyrolactone (GBL) as an industrially important product offers the possibility to use 1,4-butanediol (1,4-BDO) as a potential reactant. In this regard, different proportions of copper-based ceria catalysts (5, 10, 15, and 20CC) were synthesized using a wet impregnation method and their catalytic activities were tested for the vapour phase dehydrogenation of 1,4-BDO to GBL at temperatures from 240–300 °C. The synthesized copper-based ceria catalysts (5CC, 10CC, 15CC, and 20CC) were characterized using various analytical tools and the consequent results revealed that the activities of the CC catalysts were influenced by the physicochemical properties of the materials. In order to determine the influence of various supports on the catalytic activity, the addition of 10 wt% copper (Cu) to TiO2, Al2O3, ZnO, ZSM-5, and SBA-15 supports was carried out, and the respective influence on the catalytic activity was also experimentally established. The most outstanding catalytic activity was seen for the 10 wt% copper-based ceria catalyst, with a high conversion of 93% and selectivity of 98% at 240 °C. Factors like a high surface area, and better dispersion and basicity of active sites had a marked impact on the catalytic activity. Mechanistic analysis suggested that 1,4-BDO undergoes dehydrogenation over the copper surface to give 4-hydroxybutanal, followed by hemiacetylation and subsequent dehydrogenation to give GBL as the selective product. In terms of the stability of the catalysts, the 10 wt% copper-based ceria catalyst maintained a stable GBL selectivity of 98% for up to 7 h on-stream. [ABSTRACT FROM AUTHOR]

This study is first to demonstrate a new strategy to synthesize Cu nanoparticles (NPs) supported on TiO2 (Cu@TiO2) catalyst towards the vapor phase hydrogenation of nitrobenzene. The experimental design involved the four different loadings (10, 15, 20 and 30 wt%) of Cu NPs onto the TiO2 aerogel to produce a complex with high surface area and increased pore volume. The developed catalysts were characterized using N2 physisorption analysis, powder-XRD studies, H2-temperature programmed reduction, field emission scanning electron microscopy-EDAX, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The characterisation results specified that the surface area, mesoporosity, the effective dispersion of Cu nanoparticles onto the TiO2 support exerted a significant influence on their catalytic activities. Further, it was found that the resulted process led to the complete in situ reduction of Cu2+ to Cu0, and fine dispersion of Cu0 NPs on the surface of TiO2. Thus, no further pre-reduction of the catalyst was required. The optimized 20 wt% Cu@TiO2 catalyst achieved about 94% nitrobenzene conversion with maximum aniline selectivity (> 98%), with enhanced stability where the catalyst was found to be active up to 15 h of continuous catalytic reactions. From the study, it is found that this approach is promising and provides insights into the fundamental understanding on the importance of aerogel materials as versatile catalysts.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Levulinic acid (LA) is an industrially important product that can be catalytically valorized into important value-added chemicals. In this study, hydrothermal conversion of glucose into levulinic acid was attempted using Brønsted acidic ionic liquid catalyst synthesized using 2-phenyl-2-imidazoline, and 2-phenyl-2-imidazoline-based ionic liquid catalyst used in this study was synthesized in the laboratory using different anions (NO3, H2PO4, and Cl) and characterized using 1H NMR, TGA, and FT-IR spectroscopic techniques. The activity trend of the Brønsted acidic ionic liquid catalysts synthesized in the laboratory was found in the following order: [C4SO3HPhim][Cl] > [C4SO3HPhim][NO3] > [C4SO3HPhim][H2PO4]. A maximum 63% yield of the levulinic acid was obtained with 98% glucose conversion at 180 °C and 3 h reaction time using [C4SO3HPhim][Cl] ionic liquid catalyst. The effect of different reaction conditions such as reaction time, temperature, ionic liquid catalyst structures, catalyst amount, and solvents on the LA yield were investigated. Reusability of [C4SO3HPhim][Cl] catalyst up to four cycles was observed. This study demonstrates the potential of the 2-phenyl-2-imidazoline-based ionic liquid for the conversion of glucose into the important platform chemical levulinic acid. [ABSTRACT FROM AUTHOR]

Natural products with a variety of pharmacological effects are important sources for commercial drugs, and it is very crucial to develop effective techniques to selectively extract and isolate bioactive natural components from the plants against the background of sustainable development. Ionic liquids (ILs) are a kind of designable material with unique physicochemical properties, including good thermal stability, negligible vapor pressure, good solvation ability, etc. ILs have already been used in pharmaceuticals for extraction, purification, drug delivery, etc. It has been reported that multi-interactions, like hydrogen bonding, hydrophobic interactions, play important roles in the extraction of bioactive components from the plants. In this review, recent progress in the understanding of scientific essence of hydrogen bonding, the special interaction, in ILs was summarized. The extraction of various natural products, one important area in pharmaceutical, by conventional and functional ILs as well as the specific roles of multi-interactions in this process were also reviewed. Moreover, problems existing in bioactive compound extraction by ILs and the future developing trends of this area are given, which might be helpful for scientists, especially beginners, in this field. [ABSTRACT FROM AUTHOR]