Solvent‐Free Mechanochemical Preparation of Hierarchically Porous Carbon for Supercapacitor and Oxygen Reduction Reaction. Issue 68 (8th November 2018)

• Record Type: Journal Article
• Authors: Qi, Jiawei; Zhang, Wendu; Xu, Lang
• Is Part Of: Chemistry. Volume 24:Issue 68(2018)
• Page Start: 18097
• Page End: 18105
• Publication Date: 2018-11-08
• Subjects: biomass -- carbon -- doping -- electrochemistry -- supercapacitors; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201804302
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Hierarchically porous carbon (HPC) derived from fallen flowers was prepared by a green method of combining solvent‐free ball milling with the safe activating agent potassium bicarbonate. By regulating the mass ratio of KHCO3 to biochar, the as‐prepared HPC materials possess high specific surface areas of up to 2147.9 m 2 g −1 and abundant hierarchical pores comprised of micro‐, meso‐, and macropores. The specific capacitances of the HPC materials are able to reach 302.7 F g −1 at a current density of 0.5 A g −1 in 6 m KOH, and the symmetric supercapacitor composed of two identical HPC electrodes shows good stability because 100 % of the specific capacitance is retained after 5000 charge/discharge cycles and 90.5 % of the specific capacitance remains after 12 000 cycles. Nitrogen self‐doped HPC materials also show higher electrocatalytic activity and stronger methanol tolerance for the oxygen reduction reaction than that of the commercial Pt/C catalyst. This preparation method can be extended to the green conversion of other varieties of biomass waste into useful carbon materials. Abstract : Blossoming electrochemistry : Biomass waste‐derived hierarchically porous carbons (HPCs) are prepared by solvent‐free ball milling and KHCO3 activation (see figure). The HPCs show good electrochemical performance as supercapacitors and as catalysts for the oxygen reduction reaction.