Facile preparation of high-capacity hydrogen storage metal-organic frameworks: A combination of microwave-assisted solvothermal synthesis and supercritical activation

Abstract The Cu 3 (BTC) 2 Metal—oragnic frameworks (MOFs) are synthesized by four different processes, i.e. solvothermal method (sample 1), microwave-assisted solvothermal method (sample 2), a combination of solvothermal method and supercritical carbon dioxide (Sc-CO 2 ) activation (sample 3) and a combination of microwave-assisted solvothermal method and Sc-CO 2 activation (sample 4). By comparing the N 2 adsorption isotherms of the four samples, it is found that the sample 4 displays the greatest N 2 uptake. Due to the best performance of sample 4 in N 2 adsorption, we further study H 2 adsorption in the sample 4. Results indicate that the excess and absolute hydrogen uptakes of this material reach 4.12 and 4.49 wt% at T =77 K and P =18 bar, respectively, which is the largest one among all these reports on Cu 3 (BTC) 2 for H 2 storage at the same condition. Therefore, it is believed that a combination of the two technologies of microwave-assisted method and supercritical Sc-CO 2 activation provides a new approach for chemical engineers rapidly and efficiently preparing MOFs for high-capacity H 2 storage.