The use of chemicals as reductants and nitrogen dopants to improve the capacitance properties of reduced graphene oxide (RGO) is not only posing environmental challenges but also making the entire process expensive. Herein, we report the effectiveness of Acacia ataxacantha leaf extract as a green reductant and nitrogen dopant. The influence of the loading level of the plant extract on the structural, textural, morphological, chemical composition and capacitance properties of RGO is evaluated systematically. The X-ray diffraction (XRD) and Raman analyses revealed increased interlayer spacing and defect density with higher extract loading, while X-ray photon electron spectroscopy (XPS) confirmed successful nitrogen incorporation, particularly pyrrolic-N, which contributes to pseudocapacitance. The optimised sample (N-RGO-H 1.5 ) delivered a specific capacitance of 193 F g −1 at a current density of 0.5 A g −1 , exceeding that of pristine RGO (95.6 F g −1 ). A symmetric supercapacitor assembled with N-RGO-H 1.5 electrodes delivers an energy density of 8.33 Wh kg −1 at a power density of 199.28 W kg −1 and retains 54.02% of its initial energy density when the power density is triple, an indication that the device can be utilised for high-rate applications. The enhanced performance is attributed to the synergistic effects of nitrogen doping and improved textural properties induced by the plant extract, which promote efficient ion diffusion and charge transfer. This study demonstrates a sustainable and eco-friendly route for developing high-performance carbon-based supercapacitor materials from invasive plant resources.
Musa et al. (Thu,) studied this question.