We herein demonstrate a rational template carbonization approach to convert waste polyvinyl chloride into nanoporous carbon, in which inexpensive Mg(OH)(2) serves as hard template. The carbon-blank sample that is obtained by designating the mass ratio of polyvinyl chloride and Mg(OH)(2) as 1: 2 at the carbonization temperature of 700 degrees C is amorphous and highly porous in essence. It also exhibits large BET surface area of 958.6 m(2) g(-1), high pore volume of 3.56 cm(3) (g-1), and hierarchical pore size distribution. To further improve the electrochemical performance, various amounts of MnOx nanoparticles are incorporated into the nanoporous carbon by direct redox reaction between carbon-blank sample and KMnO4 solution at 70 degrees C. Therein, carbon-Mn2 sample (the mass ratio of carbon-blank sample and KMnO4 is 1: 1) behaves the optimal electrochemical performance. Though its porosity to some extent decreases, its specific capacitance has greatly elevated up to 751.5 F g(-1) at 1.0 A g(-1), compared with that of the carbon-blank sample (similar to 47.8 F g(-1)). The incremental capacitance of the carbon-Mn2 sample is mostly attributed to the contribution of pseudocapacitance incurred by faradic reaction of MnOx material. The present synthesis method opens up an avenue to properly dispose waste polyvinyl chloride into nanoporous carbon, especially with the promise in supercapacitor application. (C) 2015 Elsevier Ltd. All rights reserved.