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In recent years, nanotechnology has become a considerable research interest in the area of preparation of nanocatalysts based on naturally occurring polysaccharides. Chitosan (CS), as a naturally occurring biodegradable and biocompatible polysaccharide, is successfully utilized as an ideal template for the immobilization of metal oxide nanoparticles. In this study, zinc oxide nanoparticles have been doped within a chitosan matrix at dissimilar weight percentages (5, 10, 15, 20, and 25 wt.% CS/ZnO) and have been fabricated by using a simple solution casting method. The prepared solutions of the nanocomposites were cast in a Petri-dish and were subsequently shaped as a thin film. After that, the structural features of the nanocomposite film have been studied by measuring the FTIR, SEM, and XRD analytical tools. FTIR spectra showed the presence of some changes in the major characteristic peaks of chitosan due to interaction with ZnO nanoparticles. In addition, SEM graphs exhibited dramatic morphology changes on the chitosan surface, which is attributed to the surface adsorption of ZnO molecules. Based on the results of the investigated organic catalytic reactions, the prepared CS/ZnO nanocomposite film (20 wt.%) could be a viable an effective, recyclable, and heterogeneous base catalyst in the synthesis of thiazoles. The results showed that the nanocomposite film is chemically stable and can be collected and reused in the investigated catalytic reactions more than three times without loss of its catalytic activity.

Deoxygenation and decomposition of ethers and esters, including anisole, diisopropyl ether (DPE), and ethyl propanoate (EP), was investigated using bifunctional metal−acid catalysis at a gas−solid interface in the presence and absence of hydrogen. The bifunctional catalysts studied comprised Pt, Ru, Ni, and Cu as the metal components and Cs 2.5 H 0.5 PW 12 O 40 (CsPW), an acidic Cs salt of Keggin-type heteropoly acid (HPA) H 3 PW 12 O 40 , as the acid component, with the main focus on Pt−CsPW catalyst. It was found that bifunctional metal−acid catalysis in the presence of H 2 is more efficient for ether and ester deoxygenation than the corresponding monofunctional metal and acid catalysis and that metal-and acid-catalyzed pathways play different roles in these reactions. With Pt-CsPW, hydrodeoxygenation of anisole, a model for the deoxygenation of lignin, occurred with 100% yield of cyclohexane under very mild conditions (60−100 °C and 1 bar of H 2 ). This catalyst had the highest activity in anisole deoxygenation for a gas-phase catalyst system reported so far. The catalyst activity decreased in the order of metals: Pt ≫ Ru > Ni > Cu. For HPA-catalyzed DPE and EP decomposition, relationships between the turnover reaction rate (turnover frequency) and the HPA acid strength were found, which can be used to predict the activity of acid catalysts in these reactions.

The green mechanism for the synthesis of nanoparticles and their application to the wastewater treatment is of inordinate curiosity to the research community.