Search

The controlled synthesis of two‐dimensional nanocrystals of graphene particles instead of amorphous carbon quantum dots is highly challenging and requires tremendous efforts to optimize the reaction conditions. It has been observed that as a significant bio‐compatible zero‐dimensional material, graphene quantum dots are considered as a novel material for opto‐electronics, energy, biological and environmental applications. However, very few are known about their utilization in photocatalytic degradation of pesticides, especially organochlorine pesticides which are resistant to removal by conventional wastewater treatment methods. In this work, graphene quantum dots were produced from rice husk at relatively low temperatures, resulting in an average particle size of 3.3 nm. The high resolution transmission electron microscopy clearly showed the formation of spherical quantum dots having lattice fringes and the selected area electron diffraction pattern showed the crystallinity of the graphene quantum dots. A study of photodegradation of three highly toxic organochlorine pesticides namely, dichlorodiphenyl trichloro ethane, cypermethrin and fenvalerate were carried out using as‐synthesized graphene quantum dots from rice husk. Interestingly, all these pesticides were found to be degraded around 60 % to 70 % under visible light conditions. It confirmed that synthesized graphene quantum dots from rice husk can act as prominent photocatalyst for the degradation of pesticides and other pollutants. [ABSTRACT FROM AUTHOR]

Biodiesel has recently emerged as a renewable and environmentally benign fuel substitute for fossil‐derived energy sources. The use of heterogeneous solid catalysts for the generation of biodiesel from biomass‐derived fats and oils is sustainable. Among various reported catalyst supports, metal–organic frameworks (MOFs) have been popular choices for enhancing catalytic activity for biodiesel synthesis because of several outstanding features including porosity, high surface area, adjustable structures, and uniform pore sizes. In this research, the authors synthesized a novel nanocomposite of MOF‐supported hydroxyapatite (UiO‐66@HAp) using a facile impregnation technique and the characterization of the as‐synthesized catalyst was performed by different spectroscopic methods including powder X‐ray diffraction (PXRD), Fourier transform infrared (FTIR), X‐ray photoelectron spectroscopy (XPS), field emission gun‐scanning electron microscope (FEG‐SEM), energy dispersive X‐ray spectroscopy (EDS), high resolution transmission electron microscopy (HR‐TEM), thermogravimetric analysis (TGA), and N2 adsorption–desorption techniques. After successful synthesis, the catalytic property of the prepared material was evaluated in the palm oil transesterification into biodiesel. Product formation was confirmed by the 1H nuclear magnetic resonance (NMR) spectroscopy, 13C NMR, FTIR, and gas chromatography–mass spectrometry (GC–MS) of the biodiesel. The influence of different reaction variables such as catalyst dosage, methanol/oil molar ratio, temperature of the reaction, and reaction time was also studied. The outcomes revealed that the maximum biodiesel yield (∼97%) was obtained when 6 wt% catalyst was used with a 6:1 ratio of methanol/oil at 70 °C for 1 h. It was also observed that, even after 5 cycles of reuse, the catalyst was capable of producing significant amounts of biodiesel (over 90%). The results suggest that the synthesized novel catalyst holds a promising future in the sustainable production of biodiesel. [ABSTRACT FROM AUTHOR]

Many researchers have shifted their interest towards eco‐friendly, cost effective, and environmental‐based metal oxide nanoparticles. Herein, Cu2O nanoparticles are synthesized via green method for water splitting application. The prepared materials are characterized structurally and morphologically by field emission‐scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X‐ray photoelectron spectroscopy (XPS) Raman, and UV–visible spectroscopy. It is found that size and morphology depend strongly on OLE concentration and reaction time. The temperature increase leads to the formation of copper oxide (CuO) nanoparticles, which exhibit quantum confinement behavior and have an optical band gap that increases with decreasing size. Photoelectrochemical (PEC) tests of the coated graphite with Cu2O nanoparticles show a severe instability of Cu2O under irradiation due to the oxidation state that can easily change. For that, a protective overlayer of cuprous sulfide Cu2S is successfully grown on the top of Cu2O nanostructures to stabilize the photocathode. After Cu2S deposition, the measured photocurrent is significantly improved. Thus, this material is very promising for hydrogen generation by water splitting. [ABSTRACT FROM AUTHOR]

The present study was focused on green synthesis of Silver nanoparticles (AgNPs) using Trigonella foenum‐graceum L. seed extract belonging to specific variety HM (Hisar Mukta) 425, optimizing the different experimental conditions required for the formation and stability of AgNPs. UV‐Vis spectroscopy, Particle Size Analyzer (PSA), Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM), X‐ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterise the synthesised AgNPs. The average size of AgNPs was found to be 22 nm and were spherical in shape. Additionally, the United States Environmental Protection Agency (USEPA) has listed nitrophenols as a priority pollutant, and biosynthesized AgNPs can catalytically convert them into less harmful aminophenols. One example of a reaction where AgNPs are used as a catalyst is the conversion of p‐nitrophenol to p‐aminophenol, which acts as a bridge for many analgesics and antipyretic medications. Hence, the study is anticipated to have a significant impact on the pharmaceutical, cosmetic, and food industries. [ABSTRACT FROM AUTHOR]

Environmental remediation projects are becoming increasingly interested in polymers, transition‐metal oxides and graphene based nanocomposites as photocatalysts. To increase their effectiveness, they could be adjusted in conjunction with one another. A hierarchically organised nanocomposite of reduced graphene oxide based TiO2 and copolymer (Aniline and Indole) (rGO/ TiO2/P(ANI‐co‐IN)), TiO2/P(ANI‐co‐IN) and P(ANI‐co‐IN) has been synthesized by heterogeneous emulsion polymerization and is used as a catalyst for the degradation of the cationic Rhodamine (RhB) dye. Different analyses were used to characterize the resulting nanocomposites i. e. UV‐Vis diffuse reflectance spectra (DRS), Fourier Transform Infrared spectroscopy (FTIR), X‐ray diffraction (XRD), Energy Dispersive X‐Ray Spectroscopy (EDX), High Resolution Transmission electron microscopy (HR‐TEM), Selected area (electron) diffraction (SAED) and thermogravimetric analysis (TGA). DRS results revealed that the rGO/ TiO2/ P(ANI‐co‐IN) nanocomposites band gap decreased when compared to TiO2/P(ANI‐co‐IN) and P(ANI‐co‐IN). Here, rGO/ TiO2/P(ANI‐co‐IN) has outperformed every previous study on polymer/metal oxide/graphene‐based ternary nanocomposites, achieving 92 % RhB degradation within 80 min with a degradation rate constant of 0.032 min−1. The reusability of rGO/ TiO2/P(ANI‐co‐IN) was run over five cycles which bought in only a small change which could be negligible. Overall, this research may make it easier to synthesise hierarchically organised ternary nanocomposites in the future, which might be used to improve photocatalysis and address environmental protection challenges. [ABSTRACT FROM AUTHOR]

With an aim to combine the catalytic properties of Pd nanoparticles (NPs) with the excellent characteristics of porous layered double hydroxides (LDH), in the present study, four different catalysts (Pd/Fe3O4‐CoTiMgAlLDH, Pd/Fe3O4‐CoTiMgLDH, Pd/Fe3O4‐CoTiAlLDH and Pd/Fe3O4‐CoTiLDH) were synthesized by supporting Pd NPs onto four different Fe3O4‐LDH supports, which were synthesized by varying the metals in LDH. The catalytic activity of these catalysts was studied for Suzuki coupling and reductive degradation of dyes. Pd/Fe3O4‐CoTiMgLDH outperformed the other catalysts in both reactions. The synthesized catalysts were examined via different characterization techniques like X‐ray diffraction (XRD), Brunauer–Emmett–Teller analysis (BET), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), high resolution transmission electron microscopy (HR‐TEM), field emission scanning electron microscopy (FE‐SEM), energy dispersive X‐ray (EDX), energy dispersive X‐ray mapping (SEM–EDX mapping), inductively coupled plasma atomic emission spectroscopy (ICP‐AES) and vibrating sample magnetometry (VSM). On the basis of results obtained from XPS and the experimental data, Fe3O4‐CoTiMgLDH was found to be the support of choice as it not only stabilized the Pd0 NPs but also increased the electron density on the anchored Pd0 species, which enhanced the catalytic activity of Pd/Fe3O4‐CoTiMgLDH for studied organic transformations. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenide (TMDC) nanotubes complement the field of low‐dimensional materials with their quasi‐1D morphology and a wide set of intriguing properties. By introducing different transition metals into the crystal structure, their properties can be tailored for specific purpose and applications. Herein, the characterization and a subsequent preparation of single‐nanotube field emission devices of MoxWx‐1S2 nanotubes prepared via the chemical vapor transport reaction is presented. Energy‐dispersive X‐ray spectroscopy, Raman spectroscopy, and X‐ray diffraction indicate that the molybdenum and tungsten atoms are randomly distributed within the crystal structure and that the material is highly crystalline. High resolution transmission electron microscopy and electron diffraction (ED) patterns further corroborate these findings. A detailed analysis of the ED patterns from an eight‐layer nanotube reveal that the nanotubes grow in the 2H structure, with each shell consists of one bilayer. The work function of the nanotubes is comparable to that of pure MoS2 and lower of pure WS2 NTs, making them ideal candidates for field emission applications. Two devices with different geometrical setup are prepared and tested as field emitters, showing promising results for single nanotube field emission applications. [ABSTRACT FROM AUTHOR]

Metal sulfides have shown great promise for sodium‐ion batteries due to their excellent redox reversibility and relatively high capacity. However, metal sulfides generally suffer from sluggish charge transport and serious volume change during the charge–discharge process. Herein, potato chip‐like nitrogen‐doped carbon‐coated ZnS/Sb2S3 heterojunction (ZnS/Sb2S3@NC) is precisely synthesized through a sulfurization reaction, and a subsequent metal cation exchange process between Zn2+ and Sb3+. The theoretical calculations and experimental studies reveal the boosted charge transfer in ZnS/Sb2S3@NC composites. Therefore, the ZnS/Sb2S3@NC electrode exhibits excellent cycling stability (a high reversible capacity of 511.4 mAh g‐1 after 450 cycles) and superior rate performance (400.4 mAh g‐1 at 10 A g‐1). In addition, ZnS/Sb2S3@NC is based on a conversion‐alloy reaction mechanism to store Na+, which is disclosed by the X‐ray diffraction and high resolution transmission electron microscopy analysis. This effective synthesis method can provide a reference for the design of other high‐performance electrode materials for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Low loading Pton TiO2 were prepared by an impregnation‐reduction process for chemoselective hydrogenation of chloronitrobenzenes (CNBs) to chloroanilines (CANs). The structure and physicochemical properties were characterized by N2 adsorption‐desorption, X‐ray diffraction, high resolution transmission electron microscopy, X‐ray photoelectron spectroscopy and temperature programmedreduction. The low loading Pt(≤0.08 wt %) on TiO2 exhibited outstanding chemoselectivity for the catalytic hydrogenation of CNBs to CANs, without any disturbance on carbon‐chlorine bond. The characterization data suggested that the Pt particles were highly dispersed on TiO2 and strongelectronicinteractionsoccur between the dispersedPt andTiO2support, which led toelectron deficiency of nearly all Pt and production of suboxide TiOx species (x<2) in the 0.08 wt % Pt/TiO2. The electron‐deficient Pt and suboxide TiOx species favor N=O bondactivation, leading to its unique chemoselectivity. [ABSTRACT FROM AUTHOR]

Ni nanoparticles (NiNPs) were prepared by thermal decomposition of nickel acetylacetonate in the presence of a third generation polypyridylphenylene dendrimer (G3) which acts both as a coordinating ligand due to presence of pyridine groups and as a stabilizing agent due to highly branched architecture. Transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), and X‐ray photoelectron spectroscopy (XPS) were used to extensively evaluate structure and morphology of the synthesized NiNPs@G3. The selected area electron diffraction (SAED) allowed us to conclude about fcc structure of NiNPs while STEM EDS analysis demonstrated a formation of core‐shell NiO@Ni NPs. Further, the catalyst was tested in selected Suzuki‐Miyaura cross‐coupling reactions at mild conditions and demonstrated a high efficiency at low Ni loading with negligible content of Ni0 on the NP surface. The functional hyperbranched dendrimer macromolecule provided an excellent stabilization for NiNPs@G3 while allowing an easy access for reactants to catalytic sites. The high activity of the catalyst in the recycling experiments was maintained by the absence of Ni leaching from the NiNPs@G3. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms that connect heat and electron transport with crystal structures and defect chemistry is fundamental to develop materials with thermoelectric properties. In this work, we synthesized a series of self‐doped compounds Cu2+xMn1−xGeS4 through Cu for Mn substitution. Using a combination of powder X‐ray diffraction, high resolution transmission electron microscopy and precession‐assisted electron diffraction tomography, we evidence that the materials are composed of interconnected enargite‐ and stannite‐type structures, via the formation of nanodomains with a high density of coherent interfaces. By combining experiments with ab initio electron and phonon calculations, we discuss the structure–thermoelectric properties relationships and clarify the interesting crystal chemistry in this system. We demonstrate that excess Cu+ substituted for Mn2+ dopes holes into the top of the valence band, leading to a remarkable enhancement of the power factor and figure of merit ZT. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms that connect heat and electron transport with crystal structures and defect chemistry is fundamental to develop materials with thermoelectric properties. In this work, we synthesized a series of self‐doped compounds Cu2+xMn1−xGeS4 through Cu for Mn substitution. Using a combination of powder X‐ray diffraction, high resolution transmission electron microscopy and precession‐assisted electron diffraction tomography, we evidence that the materials are composed of interconnected enargite‐ and stannite‐type structures, via the formation of nanodomains with a high density of coherent interfaces. By combining experiments with ab initio electron and phonon calculations, we discuss the structure–thermoelectric properties relationships and clarify the interesting crystal chemistry in this system. We demonstrate that excess Cu+ substituted for Mn2+ dopes holes into the top of the valence band, leading to a remarkable enhancement of the power factor and figure of merit ZT. [ABSTRACT FROM AUTHOR]

A novel 2‐D flakes like Al‐BPED ((N1,N2‐bis [pyridine‐2‐yl]methyl)ethane‐1,2‐diamine) metal–organic framework (MOF) have been explored for its catalytic potential in the N‐alkylation of amines with dialkyl carbonates. The Al‐BPED MOF catalyst has been synthesized by hydrothermal route. The X‐ray diffraction, Fourier Transform Infrared Spectroscope (FTIR), and High Resolution Transmission Electron Microscopy (HRTEM) images were used to analyze the morphology of the synthesized Al‐BPED MOF samples. With the use of Al‐BPED MOF, the primary and secondary aromatic amines were selectively and efficiently methylated with dimethyl carbonate. The effect of process conditions has been investigated toward N‐methylation, N‐ethylation, and N‐benzylation of aromatic amines. Under the optimal conditions with 10 mol% of the MOF catalyst, a maximum aniline conversion of 88% and a selectivity >90% toward N‐alkylation was achieved. The kinetic studies revealed the N‐alkylation reaction in presence of Al‐BPED MOF followed pseudo‐first order rate kinetics. [ABSTRACT FROM AUTHOR]

The development of bimetallic and magnetic nanomaterials as a catalyst is highly desirable for organic transformations due to their recyclability for the sustainable future of chemical industries. Bimetallic CoNi nanoflowers were developed via the facile liquid‐phase reduction method and were employed for the hydrogenation of terminal alkynes. The structural and morphological studies were analyzed by X‐ray diffraction, Field‐Emission Scanning Electron Microscopy, and High Resolution Transmission Electron Microscopy. The bimetallic CoNi nanoflower exhibited 100 % conversion with ∼100 % selectivity towards alkane products with recyclability up to six cycles. The transfer hydrogenation mechanism was proposed via diimide formation with Co(0)/Ni(0) state, confirmed by X‐ray Photoemission Spectroscopy analysis. [ABSTRACT FROM AUTHOR]

This study explains the synthesis of cobalt‐doped dysprosium oxide nanocubes (Co‐Dy2O3 NCs) and the modification of GCE (glassy carbon electrode), for the selective and sensitive detection of riboflavin (RF). The Co‐Dy2O3 NCs were synthesized by co‐precipitation method and characterized using spectroscopic and microscopic techniques like micro‐Raman Spectroscopy, X‐ray diffraction (XRD), X‐ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FT‐IR), High‐Resolution Transmission Electron Microscopy (HRTEM), Energy‐Dispersive X‐ray Spectroscopy (EDX), and High Resolution Scanning Electron Microscopy (HRSEM). The synthesized Co‐Dy2O3 NCs were coated on the glassy carbon electrode to detect and quantify the concentration of riboflavin in aqueous and real samples. The samples were analyzed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques with three‐electrode system. The modified electrode displays two linear concentration ranges (0.5–50, 50–300 μM) with a low detection limit (LOD) of 0.094 μM and high sensitivity of 3.67 μA μM−1 cm−2. Besides, the fabricated sensor has more selectivity, great reproducibility, repeatability and good stability. Finally, the Co‐Dy2O3 NCs modified GCE based sensor was effectively applied in real sample analysis using milk and egg yolk with good recovery. [ABSTRACT FROM AUTHOR]

Mechanical stirring of bulk Te in N‐methyl‐2‐pyrrolidone (NMP) solution at room temperature resulted in the formation of free‐standing few‐layer (∼1.2–2.8 nm) crystalline ultrathin nanosheets of tellurene with a large lateral thickness (∼1–1.6 μm) as confirmed by atomic force microscopy (AFM). High‐resolution transmission electron microscopy (HRTEM) confirms the presence of α‐ and β‐phases of tellurene. First‐principle density functional theoretical (DFT) based electronic structure calculations demonstrate the indirect band gap of bi‐layer β‐tellurene. The band gap decreases with increasing number of layers in the tellurene nanosheet. [ABSTRACT FROM AUTHOR]

The current study focuses on the photocatalytic reduction of p‐nitrophenol using Europium, Yttrium and Lutetium doped Cerium oxide (CeO2) nanoparticles which were synthesized via chemical precipitation method. The synthesized nanoparticles were subjected to characterization using different analytical tools to confirm the formation of nanoparticles. They were characterized using X‐Ray diffraction (XRD) studies, Fourier Transform‐Infrared spectroscopy (FT‐IR), High resolution Scanning electron microscopy (HRSEM), High resolution Transmission electron microscopy (HRTEM), Energy dispersive X‐ray analysis (EDAX), X‐ray photoelectron spectroscopy (XPS), and UV‐Diffuse reflectance spectroscopy (UV‐DRS) studies. The synthesized rare earth nanomaterials were successfully applied for the photoreduction of the organic pollutant p‐nitrophenol with the addition of NaBH4 as reducing agent using 300 W Xenon lamp. The addition of the synthesized photocatalyst enhanced the reduction ability of NaBH4 in reducing p‐nitrophenol to p‐aminophenol. The results confirmed the superior photocatalytic activity of Lu0.05CeO2 compared to the other rare earth doped photocatalysts. The time taken by Lu0.05CeO2 photocatalyst for the complete reduction of p‐nitrophenol was 45 min and was found to be 96 % efficient in the reduction of 0.5 mM p‐nitrophenol to p‐aminophenol compared to the other photocatalysts. [ABSTRACT FROM AUTHOR]

Herein we report a facile approach for the preparation of a magnetically separable Fe3O4@poly(m‐phenylenediamine)@Cu2O nanocatalyst and its catalytic efficiency in the synthesis of 5‐phenyl‐[1,2,3]triazolo[1,5‐c]quinazolines from (E)‐1‐bromo‐2‐(2‐nitrovinyl)benzenes, aldehydes, and sodium azide under mild reaction condition is described. The morphology, chemical composition, interior structure and magnetic properties of the Fe3O4@PmPDs@Cu2O nanocomposites were studied using powder X‐ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray photoelectron microscopy, vibrating sample magnetometer and nitrogen adsorption‐desorption technique. The as‐prepared Fe3O4@PmPDs@Cu2O nanocatalyst was simply recovered using external magnet and reused up to successive six runs with no obvious loss in its catalytic efficiency and structural integrity (confirmed by powder X‐ray diffraction and transmission electron microscopy of recycled nanocatalyst) along with low leaching of copper (2.32 ppm) and iron (0.008 ppm) ions. The present protocol has a broad substrate scope with high yield in shorter reaction time and it does not require any additive or base. Overall, it has better green chemistry metrices like low E‐factor (0.93), process mass intensity (1.93), high reaction mass efficiency (51.9 %) and carbon efficiency (95 %). [ABSTRACT FROM AUTHOR]

In the present work, we have demonstrated the synthesis of Molybdenum Carbide‐reduced graphene oxide (Mo2C‐rGO) heterostructure. Uniquely, the in‐situ formation of rGO using D‐glucose in the heterostructure and its battery performance has been discussed. The High Resolution Transmission Electron Microscopy (HR‐TEM) study clearly shows the growth of Mo2C nanoparticles along with rGO confers a unique integrated layered heterostructure. X‐ray diffraction (XRD) and Raman study exhibits the formation of graphene oxide (GO) followed by multi‐layers of rGO along with hexagonal Mo2C. The electrochemical study of Mo2C‐rGO heterostructure demonstrates stable cycling performance and excellent rate capabilities. The heterostructure showed the initial capacity (1st discharge) around 632.23 mAh/g and specific capacity i. e., 537.91 mAh/g @ 0.5 A/g with 99–100 % columbic efficiency. The reversible capacities of 521.56 mAh/g, and 400.76 mAh/g were observed at current densities of 1 A/g and 2 A/g for 300 cycles, respectively, which justifies the stability of heterostructure. The cycled cell was investigated by using Electrochemical Imepedance Spectroscopy (EIS), ex‐situ XRD, and Field Emmision Scanning Electron microscopy (FESEM), which shows the negligible change in the ionic conductivity, structure, and morphology after 300 cycles. It shows the excellent stability of Mo2C‐rGO heterostructure. [ABSTRACT FROM AUTHOR]

Cobalt oxide hydrate (Co(OH)x) supported on metal oxides were prepared. The oxidative cleavage of C(OH)−C bond in alcohol was catalyzed by Co(OH)x/metal oxides using molecular oxygen as the oxidant, and the corresponding product was obtained with high selectivity. The composition and characteristics of the catalysts were analyzed by X‐ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), high‐angle ring dark‐field scanning TEM (HAADF‐STEM), N2 physico‐adsorption characterization, inductively coupled plasma optical emission spectrometry (ICP‐OES), Fourier transform infrared spectrum (FTIR), X‐ray photoelectron spectroscopy (XPS) and NH3‐temperature‐programmed desorption (NH3‐TPD). Additionally, a reasonable reaction mechanism was proposed based on the characterization results and a series of controlled experiments. Notably, this heterogeneous catalytic system did not require any additives and had good recycling performance. [ABSTRACT FROM AUTHOR]

In this paper, sulfonic acid functionalize magnetic starch (denoted Starch/SPION@SO3H) is fabricated by the polymerization of 4‐styrenesulfonic acid on the surface of magnetic starch. Magnetic starch (Starch/SPION) is synthesized by covalent modification of starch by silica capsulate superparamagnetic iron oxide nanoparticles (SPION). For this purpose, Starch/SPION is modified by allyltrimethoxysilane, follows by the polymerization of 4‐styrenesulfonic acid onto this material. The catalyst is characterized by various characterization techniques, including transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), vibrating‐sample magnetometer (VSM), X‐ray photoelectron spectroscopy (XPS), and acid/base titration. The characterizations prove the structure of Starch/SPION@SO3H catalyst. The catalytic activity of Starch/SPION@SO3H is evaluated in the multicomponent reaction of 4‐hydroxycoumarin, benzaldehydes, dimedone, and ammonium acetate for the synthesis of chromeno[4,3‐b]quinoline‐6,8(9H)‐dione derivatives. The catalyst shows very good activity in the synthesis of chromeno[4,3‐b]quinoline‐6,8(9H)‐dione derivatives. Several benzaldehydes with electron donating or electron withdrawing functionalities are used as starting material and all the substrates give the desired products in high isolated yields. In addition, the catalyst is extremely reusable during 10 sequential runs. Characterization of Starch/SPION@SO3H catalyst by TEM, VSM, and acid/base titration after recovery from the reaction proves the stability of the catalyst in the reaction conditions. [ABSTRACT FROM AUTHOR]

Computed Tomography, Catalyst Fragmentation, Metallocenes, Olefin Polymerization, Ziegler-Natta Keywords: Computed Tomography; Catalyst Fragmentation; Metallocenes; Olefin Polymerization; Ziegler-Natta EN Computed Tomography Catalyst Fragmentation Metallocenes Olefin Polymerization Ziegler-Natta 1 1 1 11/11/22 20221108 NES 221108 B The Cover Feature b shows an artistic interpretation of a supported polymerization catalyst particle that is fragmenting during ethylene polymerization. Cover Feature: Elucidating the Sectioning Fragmentation Mechanism in Silica-Supported Olefin Polymerization Catalysts with Laboratory-Based X-Ray and Electron Microscopy (ChemCatChem 21/2022). [Extracted from the article]