Issue 2, 2010

Superactivated carbide-derived carbons with high hydrogenstorage capacity

Abstract

Activation of carbide-derived carbon (CDC) with KOH generates superactivated carbons with high surface area (up to 2800 m2 g−1). The KOH activation, at a CDC/KOH weight ratio of 1 : 4, was performed at between 600 and 900 °C. Despite a 50% increase in porosity, the activated carbons retain a microporous nature with typically 90% of their surface area and 80% of their pore volume arising from micropores. The small micropores (8–12 Å) of the CDC are retained in the activated carbons, along with the generation of a greater proportion of new 20 Å pores. The size of the larger pores increases slightly at higher activation temperature. The activated carbons exhibit an enhancement of up to 63% in hydrogen uptake from 3.8 wt% for the CDC to 6.2 wt% at −196 °C and 20 bar. At 1 bar the superactivated CDC carbons store 2.7 wt% hydrogen, which is amongst the highest values ever reported for activated carbon. An increase in surface oxygen concentration also contributes to the enhanced hydrogen uptake. For example, activation at 600 °C does not alter the textural properties, but enhances hydrogen uptake by ca. 30% compared to the CDC due to an apparent higher surface oxygen concentration.

Graphical abstract: Superactivated carbide-derived carbons with high hydrogen storage capacity

Supplementary files

Article information

Article type
Paper
Submitted
06 Aug 2009
Accepted
25 Sep 2009
First published
22 Oct 2009

Energy Environ. Sci., 2010,3, 223-227

Superactivated carbide-derived carbons with high hydrogen storage capacity

M. Sevilla, R. Foulston and R. Mokaya, Energy Environ. Sci., 2010, 3, 223 DOI: 10.1039/B916197J

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