• Energy Research

This work investigates the preparation of a catalytic complex of palladium nanoparticles supported on novel Schiff base modified chitosan-Unye bentonite microcapsules (Pd NPs@CS-UN). The complex has been characterized by FT-IR, EDS, XRD, TEM, HRTEM, Raman, ICP-OES and elemental mapping analyses. Pd NPs@CS-UN was used as a catalyst for Sonogashira coupling reactions between aryl halides and acetylenes, employing K2CO3 as the base and EtOH as a green solvent under aerobic conditions in which it showed high efficacy. Pd NPs@CS-UN was regenerated by filtration after the completion of the reaction. This catalytic process has many advantages including simple methodology, high yields, and easy work-up. The catalytic performance does not notably change even after five consecutive runs.

AbstractThe application of (bio)wastes as alternatives to expensive existing catalysts is an approach that can be used to reduce environmental pollution problems. Animal bone wastes have attracted much attention as environmentally friendly heterogeneous catalysts for chemical transformations such as transesterification, oxidation, and biofuel production, owing to the substantial availability of valuable hydroxyapatite (HAp) in their structure. Most catalysts based on bone can be prepared easily by calcination. High‐temperature calcination yields highly active catalysts. Heterogeneous catalysts prepared from these renewable sources could also simply be reused and recovered without any important loss of catalytic performance. This paper reviews past efforts and recent progress on the development of different eco‐friendly catalysts derived from bone waste and some of their catalyzed chemical transformations. However, future challenges focus on crediting the conversion of unusable wastes to valuable sources to meet global requirements © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.

A mild and effective method for ultrasound-assisted N-sulfonylation of arylcyanamides with aryl sulfonyl chloride is introduced at ambient temperature; synthesis of assorted derivatives of N-cyano-N-arylbenzenesulfonamide as electrophilic cyanation agent can be further improved using Ag/feldspar nanocomposite, accessible via an simple, eco-friendly and inexpensive method using Hedera helix leaf extract. The important advantages of this method include clean conditions, high purity and yield, and easy workup procedure with minimum generation of waste. The structure and morphology nanocatalyst were characterized by energy-dispersive X-ray spectroscopy, field emission scanning electron microscope, transmission electron microscopy, X-ray powder diffraction and elemental mapping.

The fabrication of aminotetrazole–palladium(II) complex immobilized on silica-encapsulated Fe3O4 magnetic nanoparticles is described with full characterization using XRD, TGA–DTG, EDS, TEM, FESEM, VSM and FTIR spectroscopy. This prepared core–shell entity has been explored as a highly efficient reusable nanocatalyst with superior stability and high catalytic activity in the reduction of hexavalent chromium [Cr(VI)], nitroarenes and azo dyes compared to other reported Pd-based nanocatalysts. The catalytic activity of the catalyst for the reduction of Cr(VI), 2,4-dinitrophenylhydrazine, 4-nitrophenol, methyl orange, Congo red, nigrosin and rhodamine B with sodium borohydride (NaBH4) aqueous solution or formic acid is evaluated by UV–Vis spectroscopy. The present study illustrates an unprecedented example of arylaminotetrazole grafted on magnetic nanoparticles as an excellent magnetically recoverable catalyst which can be recycled seven times without any meaningful changes in the reaction time.

This study is aimed at the investigation of the preparation of sulfated lignin (SL) as a Bronsted acid catalyst for the preparation of 5-hydroxymethylfurfural (5-HMF). SL was characterized by different methods including FT-IR, FESEM, XRD, and EDS analyses. It shows promising results after 60 min of reaction at 140 °C, reaching 100% conversion of fructose precursor and 99% yield of 5-HMF, with a fructose: catalyst mass ratio of 10:6.

Pd nanoparticles (NPs)/reduced graphene oxide (RGO) nanocomposite was prepared in a one-pot process by using Euphorbia stenoclada extract as antioxidant media in the absence of any surfactant, dangerous reactants or using external energy input. Catalytic potential of the fabricated Pd-RGO nanocomposite was examined for the degradation of environmental contaminants including Cr(VI), 4-nitrophenol (4-NP), Congo red (CR), methylene blue (MB) and methyl orange (MO). The Pd-RGO nanocomposite has been thoroughly characterized by employing X-ray diffraction, UV–Vis and TEM studies. Furthermore, recyclability and reusability aspects of the nanocomposite were monitored for multiple uses without much change in catalytic activity.

AbstractThe title compounds (III) are prepared under solvent‐free conditions.

Abstract Natural sources display a high potential for the production of sustainable materials because of their exceptional structural and physical features, nontoxicity, biocompatibility, availability and cost-effectiveness. Nanostructured systems show high surface/volume ratio, and unusual electrical, mechanical, surface and magnetic properties. The preparation of heterogeneous nanocatalysts from natural resources has recently become increasingly attractive for researchers. The present overview discuses extensively and comprehensively the main natural sources used to prepare the new generation of safer and cheaper catalytic nanosystems. We place a significant emphasis on both the different synthetic strategies for the preparation of the Nature-inspired nanocatalyst and the role of the natural materials over the structural and morphological properties of the resulting nanocatalysts. The catalytic applications of nature-inspired materials were finally featured, highlighting the advantages of using nanotechnology and environmental resources as well as their potential towards the production of alternative energies.

This work reports the fabrication of Au nanoparticles (NPs) by laser ablation of a gold metal plate immersed in water in the absence of stabilizing agents and their application in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) using sodium borohydride (NaBH4) in aqueous media at ambient temperature. UV–Vis, EDS (energy-dispersive X-ray spectroscopy), FESEM (field emission scanning electron microscopy), transmission electron microscopy and inductively coupled plasma-optical emission spectrometry analyses have been applied for the characterization of Au NPs which affirmed that they were successfully synthesized and their size ranged from 5–30 nm. The reduction rate for 4-NP with Au NPs using NaBH4 was measured via UV–Vis spectroscopy from 250 to 550 nm. The clean and eco-friendly protocol presented here neither produces hazardous wastes nor uses any toxic organic solvents, hazardous reductants and expensive surfactant template or capping agents; Au NPs display high catalytic activity as the reaction was completed within 20 min with 100% conversion. Greener preparation of Au nanoparticles by Q switched laser ablation and their application in 4-nitrophenol reduction