Cellulose degradation of cottonseed meal derived porous carbon for supercapacitor

Abstract

Enzyme, as a type of biocatalyst, has a superior degradability on the biomass component. Herein, the cellulase degradation of cottonseed meal (CCM) is used as carbon source and potassium citrate as activating agent to fabricate O, S, N co-doped carbon materials. Cellulase pretreatment degrades the cellulose (from 12.48 wt% to 2.24 wt%) of cottonseed meal (CM) as well as creates the pore structure. Most importantly, the enzymolytic process can enhance the O content and improve the activation efficiency of potassium citrate. The optimized CCM-800-2 with hierarchical porous structure and high O (11.33 at%) content exhibits a high specific capacitance of 364 F g-1 in 6 M KOH electrolyte. In addition, the assembled potassium citrate-chitosan gel electrolyte-based symmetric supercapacitor with 20 mg cm-2 mass loading of active material shows a high energy density of 28.8 Wh kg-1. This study provides an efficient enzyme assisted pretreatment and low activator ratio strategy to prepare biomass-based porous carbon, and expects to fabricate more carbon materials using other carbon precursors.