The activated carbon biomass was prepared using KOH activator, and thiourea precursor, which were activated at 400, 5000, and 600 C, and labelled as PJ1, PJ2, and PJ3, respectively and undoped PJ3 was also prepared for comparison studies. The PJ3 exhibited the maximum SBET of 570.54 m 2 g -1 , and the pore volume of 0.324941 cm carbon (NC-800-2) was prepared using HCl as catalyst. Further, NPC-X samples were prepared using 1, 2, and 3 mL of H3PO4 and carbonized at 800 ˚C but was not activated. The SBET of NPCs was increased from 1294 m 2 g -1 (NPC-800-1) to 1877 m 2 g -1 (NPC-800-2), and decreased to 1176 m 2 g -1 on increasing the KOH rate (NPC-800-3). It is obvious from BET analysis that, the overuse of KOH resulted in the collapse of micropores, and mesopores, and thereby lowered the SBET. Moreover, the SBET, and microporous volumes of NPC-x-2 were continuously increased from 1375 m 2 g -1 and 0.045 m 3 g -1 to 2024 m 2 g -1 and 0.53 m 3 g -1 , as the activation temperature raised from 700 to 900 ˚C, respectively, and suggested the influence of activation temperature towards SBET and pore structure. The presence of N, O, and P heteroatoms were confirmed from XPS analysis, and confirmed the effect of activation temperature on the surface atomic content of N and P. NPC, NPC-700-2, NPC-800- temperature, a decrement in the surface atomic content of N and P was observed due to the strong KOH etching at higher temperature. The capacitive performance of NPCs was evaluated using 6 M KOH solution in a three-electrode system. NPC-800-2 electrode exhibited the highest specific capacitance of 302 F g -1 at 0.5 A g -1 , whereas NPC showed the lowest supercapacitive properties were studied using 6 M KOH solution in three-electrode system.