Synthesis and characterization of Cu doped activated carbon beads from chitosan

• Published in: Microporous and mesoporous materials 2021-07, Vol.322, p.111147, Article 111147
• Main Authors: Guy, Fabrice, Runtti, Hanna, Duclaux, Laurent, Ondarts, Michel, Reinert, Laurence, Outin, Jonathan, Gonze, Evelyne, Bonnamy, Sylvie, Soneda, Yasushi
• Format: Article
• Language: English
• Subjects: Activated carbon; Analytical chemistry; Bead; Chemical and Process Engineering; Chemical Sciences; Chitosan; Engineering Sciences; KOH activation; Material chemistry; Nitrogen doping; Porosity
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2021.111147

New types of Cu-doped spherical-shaped activated carbons were prepared by pyrolysis at 700 °C of chitosan hydrogels impregnated with KOH at ratios (mKOH/mchitosan) ranging from 22.5% to 135%. At KOH impregnation ratio lower than 63%, the precursor Cu doping allowed obtaining bead-shaped activated carbons (diameter ~ 2 mm) and the highest specific surface areas (1145 m2 g−1). The absence of copper doping yielded to activated carbon powders whatever the KOH impregnation ratio. As increasing the impregnation ratio higher than 63%, the materials porosity type turns from exclusively microporous to both microporous and mesoporous. The microporous volume, determined by N2 adsorption at 77 K and CO2 adsorption at 273 K, attains a maximum (about 0.5 cm3 g−1) for a 63% impregnation ratio. Scanning Electron Microscopy (SEM) images show a multi-scale porosity for a KOH impregnation ratio higher than 45%. Nanoparticles of Cu and CuO were identified by SEM and Transmission Electron Microscopy in the ACs beads prepared from copper-doped chitosan. Whatever the composition, the beads are formed of N-enriched carbons showing mainly pyridinic and pyrrolic groups evidenced by XPS. [Display omitted] •Activation at 700 °C of KOH impregnated chitosan hydrogels beads.•Preparation of new types of Cu-doped spherical-shaped activated carbons.•KOH impregnation ratio of 63% optimised to obtain the highest micro-mesopore volume.•Presence of Cu/CuO nanoparticles observed by electron microcopy methods.•N-enriched carbons showing mainly pyridinic and pyrrolic groups evidenced by XPS.