Magnetic nitrogen-doped carbon derived from silk cocoon biomass: a promising and sustainable support for copper

In this study, a magnetic nitrogen-doped carbon-based copper (MNC-Cu) catalyst was fabricated so that natural silk cocoons undergo thermal processes and then activate by combining with Fe 3 O 4 MNPs as a suitable substrate for placement copper metal. The efficiency of the generated catalyst in the synthesis of 5-substituted 1 H -tetrazole derivatives was evaluated by the [3 + 2] cycloaddition reaction of aromatic aldehydes, azide ions, and hydroxylamines. FT-IR, FE-SEM, EDS, TEM, XRD, TGA, and VSM techniques have been adopted to identify and validate this heterogeneous catalyst. The observation from EDS, elemental mapping, XRD, and FT-IR analysis confirms the immobilization of Cu metals on the MNC surface and uniform distribution of species and then no aggregation occurs during functionalization. VSM results show the magnetic feature of fabricated catalyst, and based on the leaching test, the amount of catalyst leaching was negligible. Moreover, this reaction is a one-pot multicomponent reaction (MCRs) or more precisely a one-pot, three-component reaction, which is one of the advantages of this work. The fabricated catalyst shows high efficiency, good stability, and considerable reactivity in synthesizing 5-substituted 1 H -tetrazole derivatives. So it can be seen that the fabricated magnetic catalyst is a useful and practical catalyst for synthesizing [3 + 2] cycloaddition reactions. Reusability and recyclability for five sequential runs without notable increase and reduction in activity are other advantages. In addition, the magnetic properties of this heterogeneous catalyst led to easy and quickly recovered and striking copper leaching. Graphical abstract