Structural Analysis of Furfural Resin-based Active Carbon to Control an Electric Double-layer Capacitor

• Published in: Denki kagaku oyobi kōgyō butsuri kagaku Vol. 88; no. 3; pp. 127 - 131
• Main Authors: HOKARI, Kanade, SUZUKI, Shinichiro, OKAMOTO, Naoki, SAITO, Takeyasu, IDE, Isamu, NISHIKAWA, Masanobu, ONISHI, Yoshikazu
• Format: Journal Article
• Language: English
• Published: Tokyo The Electrochemical Society of Japan 05.05.2020; Japan Science and Technology Agency
• Subjects: Activated carbon; Active Carbon; Active control; Capacitors; Carbon; Carboxyl group; Carburizing; EDLC; Functional groups; Furfural; Furfural Resin; Nitrogen; Particle size distribution; Photoelectron spectroscopy; Photoelectrons; Pore size; Pore size distribution; Pores; Porosity; Potassium; Potassium hydroxide; Potassium hydroxides; Resins; Size distribution; Specific capacity; Structural analysis; Surface Chemical Structure; Titration
• ISSN: 1344-3542; 2186-2451
• DOI: 10.5796/electrochemistry.20-63004

Active carbon was prepared by treating carburized furfural resin particles (1 µm in diameter) with potassium hydroxide solution for 0–0.5 h at 700–800°C in flowing nitrogen gas. The pore structure of the active carbon was then evaluated by nitrogen adsorption experiments. The active carbon particles (1 µm in diameter) prepared at 750°C-0 h or 800°C-0 h had ca. 2.5-fold greater mesopore volume and 1.9-fold greater mesopore ratio than those prepared at 700°C-0.5 h. The surface chemical structure was evaluated by X-ray photoelectron spectroscopy, while the fraction of organic functional groups in the pores was evaluated by Boehm titration. The carboxyl group fraction in the pores increased in the following order: 750°C-0 h (18.1%) < 800°C-0 h (23.0%) < 700°C-0.5 h (31.4%). The relationship between the pore size distribution, surface functional groups in the pores, and electric double-layer capacitor capacity was investigated for the specific surface area of 1200 ± 100 m2/g. The specific capacity increased in the following order: 700°C-0.5 h (66 F/g) < 800°C-0 h (111 F/g) < 750°C-0 h (148 F/g). This indicated that the amount of surface functional groups played a crucial role in the 6 M KOH electrolyte.