Zinc oxide on biochar wased-drived support as nanocomposite catalyzed synthesis of tetrahydrobenzo[a]xanthen-11-one and 5-aminopyrazole-4-carbonitrile derivatives

This study prepared biochar/zinc oxide composite nanoparticles as a reusable and environmentally friendly biocatalyst. The favorable oxygen-containing functional groups, porous structure, and stability of biochar makes it an excellent support for metal phases, enhancing catalytic activity in reactions. Furthermore, the incorporation of zinc oxide nanoparticles provides a synergistic effect, contributing to a higher surface area and improved active sites for catalytic reactions. The composite material was characterized by various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), wavelength dispersive X-ray spectroscopy (WDX), Brunauer–Emmett–Teller (BET), thermal gravimetry analysis (TGA), and Fourier-transform infrared spectroscopy (FT-IR) to confirm the formation of the nanocomposite and analyze its morphology. The catalytic performance of the biochar/zinc oxide composite was evaluated in the one-pot, three-component synthesis of tetrahydrobenzo[a]xanthenes-11-one derivatives at 100 °C under solvent-free conditions as well as for 5-aminopyrazole-4-carbonitrile derivatives in a 1:2 ethanol–water mixture at 50 °C. The results suggest that this biocatalyst holds great promise for various applications in environmental remediation and sustainable chemistry because of its high efficiency and reusability.

Graphical abstract