A new route for conversion of corncob to porous carbon by hydrolysis and activation

• The new route could convert waste corncob to high performance carbon materials.
• This route was realized by the process of acid hydrolysis and alkali activation.
• High surface area (up to 3611 m2/g) was achieved.
• Porous carbon had specific capacitance of up to 236 F/g.
• This route could be readily extended to abundant lignocellulose biomass and industrial wastewater containing carbohydrates.

A new route for conversion of corncob to high performance porous carbon was proposed. This route involved hydrolysis of corncobs to dissolved sugars and degradation products of carbohydrates by sulfuric acid catalysis, transformation of the liquid hydrolyzate into solid hydrochar by dehydrating, polymerization and carbonization, fabrication of porous structures by activation. By using this route, high surface area (up to 3611 m2/g) and low ash content (0.51 wt%) were achieved. A cottony structure appeared on the surface of the porous carbon in a high KOH/hydrochar ratio. The specific capacitance for porous carbon was up to 236 F/g, which indicated the excellent electrochemical properties of these materials. Furthermore, the highly developed pore structures made the porous carbon possess potential applications in separation, catalysis, hydrogen storage and other fields.