Preparation, Electrochemical Characterization and Vapour Sensing Application of Nanoporous Activated Carbon derived from Lapsi

Activated carbon (AC) has been successfully prepared from agricultural waste lapsi seed stone. The phosphoric acid activation was done by varying the ratio of H3PO4 and lapsi seed powder (LSP) from (0.9:1) to (1.5:1) which was followed by carbonization at 400°C in a tubular furnace under nitrogen atmosphere for 3 hrs. Besides this, precursor was preheated to 200˚C for 2-6 hrs. Thus prepared material was characterized by BET N2 adsorption- desorption process and showed high 1500 m^2/g surface area with high pore volume. The electrochemical characterization was carried out using three electrode system where carbon electrode was used as working electrode, platinum as counter electrode and Ag/AgCl electrode as a reference electrode. CV has been found operating in acidic electrolyte solution of (1 M) H2SO4. The results revealed a very promising capacitance value of 202 F/g at current density of 1 A/g. Charge– discharge measurement showed a good indication of stable cyclic performance up to 1000 cycles at current density of 5 A/g. Such electrochemical properties exhibited the high prospect for development of energy storage materials. As prepared activated carbon also showed excellent sensing ability towards vaporized solvent gases like methanol, acetone, benzene, hexane, pyridine, formaldehyde, toluene, water, acetic acid, ammonia.