Pd immobilized on the composite of halloysite and low-cost bio-based eutectic solvent-derived carbon: An efficient catalyst for hydrogenation in the presence of cyclodextrin

Using urea and glucose as cost effective and available raw materials, a eutectic solvent, was fabricated and applied as a precursor to form N-doped carbon. Subsequently, the eutectic solvent-derived carbon was reacted with halloysite nanoclay through hydrothermal process to produce a novel nanocomposite. The resultant compound was utilized as a support for the immobilization of Pd nanoparticles. The final nanocomposite was then employed as a highly active and selective catalyst for promoting hydrogenation reaction of nitroarenes in the presence of cyclodextrin as co-catalyst. To elucidate the roles of the eutectic solvent-derived carbon, halloysite and the ratio of halloysite: eutectic solvent-derived carbon in the catalysis, several control samples were prepared and their activities were compared with that of the catalyst. Furthermore, the role of cyclodextrin in the catalysis was approved by comparing the catalytic efficiency of the catalyst in the absence and the presence of cyclodextrin. It was found that cyclodextrin exerted its role via acing as phase transfer agent, while eutectic solvent-derived carbon could significantly increase the Pd loading. On the other hand, the ratio of halloysite: eutectic solvent-derived carbon could influence the performance of the catalyst. Notably, the catalyst was recyclable up to six reaction runs.