Synthesis of Biochar-Like Graphene Nanosheets (BLG) from Candlenut Shells with Integrated Conductive and Antibacterial Functionalities

Abstract

Graphene’s exceptional electrical, mechanical, and chemical properties have enabled breakthroughs in electronics, energy storage, and biomedicine, yet large-scale, low-cost, and sustainable production methods remain elusive. Here, we report a facile, scalable route to synthesize Biochar-Like Graphene Nanosheets (BLG) from candlenut shell biomass using activated carbon as a dual-function reducing agent and combustion inhibitor in a modified muffle furnace pyrolysis system. Structural analysis by X-ray diffraction and Fourier-transform infrared spectroscopy confirms the formation of defect-rich, low-oxygen sp² carbon networks, while scanning electron microscopy reveals wrinkled layered morphologies that promote electrolyte accessibility. Electrical measurements demonstrate a voltage-dependent conductivity, reaching 368.67 μS·cm⁻² at 1.5 V, alongside stable power density (6.72 W·kg⁻¹) and high energy density (403.2 Wh·kg⁻¹), indicative of excellent charge transport and storage capabilities. Remarkably, BLG exhibits potent antibacterial activity against Salmonella typhimurium with a 10.76 ± 0.23 mm inhibition zone and positive MIC and MBC responses, attributed to synergistic membrane disruption, reactive oxygen species generation, and electron transfer effects. This biomass-to-graphene strategy offers a sustainable, multifunctional nanomaterial platform for next-generation energy, environmental, and biomedical technologies