Ordered porous carbon with pore size of 80 nm (C80) was treated in concentrated nitric acid to investigate the effect of the functional groups on the electrochemical properties in supercapacitors. The optimum oxidation time for C80 with good supercapacitive performance in acidic and basic electrolytes was determined. The increase of nitrogen and oxygen groups in the surface results in the improvement of wettability. Though the decreased specific surface area, a remarkable increase in the specific capacitance was observed in the as-modified C80 due to the introduction of the nitrogen and oxygen functional groups. The modification of C80 via oxidation approach demonstrates an effective way to improve the wettability and electrochemical properties. (c) 2013 Elsevier Ltd. All rights reserved.