Efficient Catalytic Synthesis of <i>N</i> ‐Heterocyclic Derivatives Using Low Loading Cerium Modified Medicinal Residue Biochar Catalyst in Green Solvents

ABSTRACT In this work, low‐metal cerium‐supported biochar composite catalytic materials (Ce 3.0 ‐NC) were successfully prepared by the hydrothermal synthesis method. It was confirmed by characterization methods such as XRD, HR‐TEM, Raman, and EPR that Ce 3.0 ‐NC has excellent catalytic activity and structural stability. This catalyst efficiently catalyzes the synthesis of three types of nitrogen‐containing heterocyclic derivatives in aqueous phase or water/ethanol mixed solvents under low‐temperature and short‐time conditions: tetraketones (yield 75%–99%), quinolines (yield 76%–99%), and quinoxalines (yield 42%–90%). The reaction system does not require a protective atmosphere or alkaline reagents, and has the advantages of mild conditions, green solvents, and high catalytic efficiency. After 7 cycles of use, there was no significant decline in Ce 3.0 ‐NC catalyst activity. This study provides a new approach for the high‐value utilization of biomass carbon from medicinal residue, achieving the green preparation of low‐load metal‐doped biochar and the efficient synthesis of nitrogen‐containing heterocyclic compounds.