Electrochemical exfoliation of graphite using aqueous ammonium hydrogen carbonate solution and the ability of the exfoliated product as a hydrogen production electrocatalyst support

Ryuichi Maekawa; Hirooki Kajiwara; Yuto Washiyama; Yasushi Nishikawa; Naoto Kuwamura; Toshinori Okura; Yuta Nishina; Hideki Hashimoto

doi:10.1016/j.heliyon.2024.e40751

Electrochemical exfoliation of graphite using aqueous ammonium hydrogen carbonate solution and the ability of the exfoliated product as a hydrogen production electrocatalyst support

Heliyon. 2024 Nov 28;10(23):e40751. doi: 10.1016/j.heliyon.2024.e40751. eCollection 2024 Dec 15.

Authors

Ryuichi Maekawa¹, Hirooki Kajiwara¹, Yuto Washiyama², Yasushi Nishikawa³, Naoto Kuwamura⁴, Toshinori Okura², Yuta Nishina^{5

6}, Hideki Hashimoto²

Affiliations

¹ Applied Chemistry and Chemical Engineering, Graduate School of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo, 192-0015, Japan.
² Department of Applied Chemistry, School of Advanced Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo, 192-0015, Japan.
³ Kaneka Corporation, 5-1-1 Torikainishi, Settu, Osaka, 566-0072, Japan.
⁴ Division of Liberal Arts, Center for Promotion of Higher Education, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo, 192-0015, Japan.
⁵ Research Core for Interdisciplinary Sciences, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan.
⁶ Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan.

Abstract

Electrochemical exfoliation of graphite has attracted much attention as a practical mass production of two-dimensional graphene-like materials. There is an increasing desire to find new and improved methods to create unique exfoliated products with excellent functionality. We used aqueous ammonium hydrogen carbonate solution as a new electrolyte for anodic oxidative exfoliation of graphite. The exfoliated product has a porous two-dimensional structure, and it can be dispersed in water for over five years. The oxidized and defected porous surface serves as an ideal support for molecular metal complexes, effectively functioning as heterogeneous electrocatalysts for hydrogen production.

Keywords: Carbon materials; Nanocomposites; Oxidation.