Facile preparation of nitrogen-doped porous carbon from waste tobacco by a simple pre-treatment process and their application in electrochemical capacitor and CO 2 capture

•A pre-treatment process is used to prepared N-doped carbon from waste biomass.•Waste tobaccos, which are limited for the disposal, are used as the raw materials.•The product shows a specific surface area and nitrogen content.•Its electrochemical performance is better than commercial activated carbon.•Its CO2 sorption performance is also better than commercial activated carbon.