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A biopolymer cellulose-based magnetic composite nanocatalyst was prepared and characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Then, it was used efficiently in the multicomponent synthesis of polysubstituted pyridines under mild reaction conditions and using an easy work-up procedure at room temperature in ethanol. The nanocatalyst can be recovered easily and reused several times without significant loss of catalytic activity.

In this study, for the first time, carbon paste electrode (CPE) was modified with palladium nanoparticles supported on ethylenediamine-functionalized cellulose (PdNPs@EDAC-CPE), and its performance for electrocatalytic hydrogen production was examined. Field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX) were used to study the morphology and structure of PdNPs@EDAC, respectively. The electrochemical characterizations were performed using cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). To optimize conditions, the influence of some parameters including the amounts of PdNPs@EDAC and binder in the electrode composition and the electrolyte type and its pH were examined on the hydrogen production process. Comparison of the proposed electrode with the CPE, CPE modified with functionalized cellulose (EDAC-CPE) and CPE modified with Pd (Pd-CPE) showed that PdNPs@EDAC-CPE has the best performance. The proposed electrode with the very low loaded Pd includes several advantages such as using cellulose as a biodegradable polymer, low cost, very good performance and ease of preparation in a large scale that could be a perfect candidate for high-purity electrocatalytic hydrogen production.

Hantzsch 1,4-dihyropyridine synthesis is one of the multicomponent reactions that is accomplished with different catalyst and under different conditions. In this work, this one-pot three-component and four-component reactions for the synthesis of 1,4dihyropyridine and polyhydroquinoline derivatives are described in the presence of biopolymer-based gamma-Fe 2 O 3 /Cu/cellulose as a nanocatalyst. This magnetic catalyst was very effective for this reaction, and it was carried out by simple work-up procedure under green and environmentally friendly conditions in ethanol at room temperature.