Mechanism of porosity development and defect engineering in chemically activated woven carbon fibres

Carbon cloths (CCs) with their woven fibres are known to be inert with low specific surface area (SSA). To overcome these issues, activated CCs (ACCs) by potassium hydroxide (KOH) were chemically etched to create pores on the fibre surface homogeneously. Herein, various weight ratios (WRs) of the CCs to the etchant (KOH) were adopted to understand the pore development mechanism. The SSA of the ACC with a WR = 0.01 wt%/wt% was enhanced more than 15 times compared to that of the neat CC originating from outside-in pore deepening as the predominant mechanism for the pore growth as well as the intercalation of the metallic potassium during an etching redox reaction. Additionally, the defective sites across the fibre can be tuned by altering the bond angle and changing the orientation of basal planes through the KOH introduction, as proved by vibrational spectroscopy. The variation of activation conditions was correlated with the surface energy by comparing the role of constituted dispersive and specific energy components. Compared to the previously conducted research, the activated carbon fibres of this study with their outstanding features have provided insight into the pore development and defect engineering that can be applied for environmental or energy applications.

Automated summary

Chemical etching of carbon cloths (CCs) with potassium hydroxide (KOH) has been used to enhance their specific surface area (SSA). Different weight ratios (WRs) of CCs to KOH were investigated to understand pore development mechanism. The activated CCs with a WR of 0.01 wt%/wt% showed more than 15-fold increase in SSA compared to neat CCs, primarily due to outside-in pore deepening and metallic potassium intercalation. The introduction of KOH also affected defective sites and surface energy.