Abstract

 Preparation of carbon from papaya (Carica papaya L.) seeds activated with ZnCl2 @ 300°C is presented. Characterization of the powder is carried out by elemental analysis, N2 sorption studies, powder x-ray diffractometry, fourier transform infrared spectroscopy, scanning electron microscopy, cyclic voltammetry and galvanostatic charge-discharge studies. Specific capacitance from cyclic voltammetric studies on the carbon is 472 F g-1 in 1M H2SO4 electrolyte when run between -0.1 and 1.0V Vs SCE at 10 mV s-1 scan rate. The proposed carbon sample posses an N2 adsorption isotherm characteristic of mesopore structures. The presence of various surface functional groups like carbonyl and hydroxyl groups coupled with desired physical features of the carbon are presumed to be responsible for fast faradic reactions to offer pseudocapacitive characteristics to the papaya derived carbon. Capacity as well as the cycling stability of the electrode prepared with papaya seed based activated carbon in acid electrolyte seems to be impressive as observed from charge-discharge studies. Thus papaya seed biomass represents a promising new green source of carbon for electrochemical capacitor electrodes and gives a new and valuable dimension to domestic wastes.

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