Methane storage in zeolite-like carbon materials

Abstract

High specific surface area zeolite-like carbon materials (CZ) were synthesized by combining the hard template method with the Chemical Vapor Deposition (CVD), using zeolite beta as solid template and acetylene as carbon precursor, at different reaction temperatures (1023, 1073 and 1123K). CZ materials were characterized by X-ray diffraction, Scanning Electron Microscopy and nitrogen adsorption–desorption measurements. The nanoporous CZ materials possess surface areas up to 1130m2/g and total pore volumes up to 0.75mL/g while XRD data and SEM images show the successful replication of the structure and morphology of the zeolite particles into the final carbon materials. Methane storage properties at different temperatures (287, 298 and 313K) have been investigated by Sievert’s-type apparatus up to 3.5MPa. The CZ materials exhibit a high and reversible methane storage capacity, with measured gravimetric uptake up to 8.0wt% at 298K and 3.5MPa, a much higher value compared to the pristine zeolite beta which shows gravimetric methane adsorption capacity up to 1.5wt% at the same conditions. The analysis of the obtained isotherm curves by Tόth model shows the same grade of homogeneity on sample porosity for all probed samples while the evaluation of the adsorption enthalpy at low pressures reveals a similar binding energy between the methane molecules and the samples’ surfaces despite of their different long range order.