Activated carbon xerogels with a cellular morphology derived from hydrothermally carbonized glucose-graphene oxide hybrids and their performance towards CO2 and dye adsorption

摘要

We report the preparation of micro-/mesoporous carbon monolithic xerogels by means of a two-step approach that comprises (1) hydrothermal carbonization of glucose in the presence of graphene oxide (GO) sheets as morphology-directing agents and (2) chemical activation of the resulting hydrothermal carbon (HTC) xerogels with KOH. The as-prepared HTC xerogels were made up of a random assembly of thin (<30 nm) carbon platelets, which were interpreted to arise via dehydration and condensation reactions of glucose at catalyt-ically active (acidic) sites present on the surface of GO. The chemical activation afforded xerogels with large surface areas and pore volumes (up to ~2000 m~2 g~(-1) and 1.15 cm~3 g~(-1), respectively) and a cellular morphology, which could be attributed to the combined effect of the activating agent and the unusual, compliant nature of the HTC xerogel. Additionally, the use of different activation conditions allowed fine-tuning the porous texture of the activated xerogels. Finally, the activated carbon xerogels displayed CO2 uptake capacities up to 4.9 mmol g~(-1) at 0°C and 1 bar, as well as an efficient performance (between 600 and 700 mg g~(-1)) in the adsorption of bulky dyes, thus demonstrating their application potential.