▎ 摘　　要

The key feature of the present work is the dexterous utilization of an apparently destructive process, pyrolysis, for the synthesis of the most esteemed nanomaterial, graphene. This work is an attempt to synthesize graphene from nonconventional sources such as tannic acid, alginic acid, and green tea by a controlled pyrolysis technique. The precursors used in this work are not petroleum-derived and hence are green. A set of pyrolysis experiments was carried out at different temperatures, followed by a thorough step-by-step analysis of the product morphology, enabling the optimization of the graphitization conditions. A time-dependent morphological analysis was also carried out along with isothermal thermogravimetric studies to optimize the ideal pyrolysis time for graphitization. The specific capacitance of the graphene obtained from alginic acid was 315 F/g, which makes it fairly suitable for application as green supercapacitors. The same graphene was also used to fabricate a rubber-latex-based flexible supercapacitor film with 137 F/g specific capacitance. The graphene and graphene-based latex film exhibited room-temperature magnetic hysteresis, indicating their ferromagnetic nature, which also supports their spintronic applications.