Gas adsorption study on HKUST-1 of different particle size

Metal Organic Frameworks (MOFs) are polymeric crystalline materials with extremely high surface areas and chemically modifiable structures [1] that have attracted much interest both from academic and industrial side. Their features make them potentially applicable in many different technological fields such as heterogeneous catalysis, biomedicine or gas separation and storage. Of particular interest is their use for the storage/separation of energetically and environmentally relevant gases such as H2, CH4 and CO2. One of the most studied and promising MOF prepared until now is HKUST-1 system or [Cu3(BTC)2(H2O)3]n (H3BTC = benzene-1,3,5-tricarboxylic acid) [2]. Its synthesis has been widely investigated by exploring different experimental conditions in order to control particle dimension and morphology. Moreover, HKUST-1 has been recently evidenced as one of the best performing systems for methane storage [3]. In this contribution we report a study based on the nitrogen and methane adsorption properties, both adsorption capacity and adsorption kinetics, of a series of HKUST-1 samples featuring different particle sizes. Tuning of particle dimensions have been done by following literature procedures [4], that is, by varying reaction conditions (i.e. solvent, temperature, etc.) or exploiting the use of additives. Crystal sizes have been characterized by SEM and X-Ray powder diffraction experiments. The effect of the crystal size on the adsorption kinetics and total adsorption capacity for HKUST-1 will be here discussed. [1] S. Kitagawa, R. Kitaura and S. Noro, Angew. Chem., Int. Ed., 2004, 43, 2334; (b) M. Eddaoudi, J. Kim, N. Rosi, D. Vodak, J. Wachter, M. O'Keeffe and O. M. Yaghi, Science, 2002, 295, 469; [2] S. S.-Y. Chui, S. M.-F. Lo, J. P. H. Charmant, A. G. Orpen, I. D. Williams, Science, 1999, 283, 1148. [3] J. A. Mason, M. Veenstra, J.R. Long, Chem. Sci, 2014, 5, 32; Y. Peng, V. Krungleviciute, I. Eryazici, J. T. Hupp, O. K. Farha, T. Yildirim, J. Am. Chem. Soc., 2013, 135 11887. [4] G. Majano and J. Pérez-Ramírez.,Helvetica Chimica Acta, 2012, 95, 2278. (b) R. Ameloot, E. Gobechiya, H. Uji-i, J. A. Martens, J. Hofkens, L. Alaerts, B. F. Sels, and D. E. De Vos. Adv. Mater. 2010, 22, 2685. Acknowledgment Authors acknowledge financial support from the MINECO (Concert project-NASEMS (PCIN-2013-057)) and Regione Lombardia (Concert project-NASEMS (Concert_EN-046)).