H 2 and CH 4 Sorption on Cu-BTC Metal Organic Frameworks at Pressures up to 15 MPa and Temperatures between 273 and 318 K

Abstract

Sorption isotherms of methane and hydrogen on Cu3(BTC)2 have been measured in the temperature range from 273 to 318 K and at pressures up to 15 MPa. H2 excess sorption capacities of the Cu3(BTC)2 amounted to 3.9 mg/g at 14 MPa. Promising maximum CH4 excess sorption capacities on the same sample were reached at approximately 5 MPa. They amounted to 101, 100, 92 and 80 mg/g at 273, 278, 293 and 318 K, respectively. The sorbed phase density was essen- tially the same for all temperatures and amounted to ~600 kg/m3. Structural changes of the Cu3(BTC)2 samples after thermal activation and treatment with high pressure H2 and CH4 were tested. It was found that the initial micropore structure has virtually disappeared as evidenced by a decrease of the Langmuir specific surface area by a factor ~3 and CO2 micropore volume by a factor of ~4 for H2 and ~3 for CH4. This is in line with an increase in the average pore di- ameter from initially 9.2 to 15.7 for H2 and 12.8 for CH4