Moganesh Govindhan
A sustainable, metal-free photothermal strategy is reported for synthesizing oxygen-rich nanosized particles (D-NPs) from Datura metel plant extract without chemical activators or metal precursors. Halogen-lamp–induced photothermal processing enables controlled fragmentation and partial carbonization of plant-derived organics, yielding nanoscale carbonaceous particles enriched with electrochemically active oxygen functionalities. Structural and spectroscopic analyses confirm the formation of a defect-rich, turbostratic–amorphous carbon framework with uniformly distributed hydroxyl, carbonyl, and ether groups. Thermogravimetric analysis reveals enhanced thermal stability, with minimal mass loss below 350 °C and ∼86% residue above 550 °C. Electrochemical evaluation in 1 M KOH demonstrates hybrid capacitive behavior, delivering a specific capacitance of 232.4 F g⁻¹ at 2 A g⁻¹ and 83% capacitance retention over 5000 cycles. Device-level energy and power densities further highlight the practical potential of this green, biomass-derived electrode material for supercapacitor applications.