Quantum Sieving Effect Of Three-Dimensional Cu-Based Organic Framework For H2 And D2
Katsumi Kaneko, Chiba University, Faculty of Science, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba-city, 263-8522, Japan, Chiba, 263-8522, Japan
The authors found remarkable soft nature of Cu-based organic framework on gas adsorption in the preceding report. This paper describes new quantum molecular sieving effect of new type of Cu-based MOF. The crystal structure of [Cu(4,4'-bipyridine)2(CF3SO3)2]n metal-organic framework (CuBOTf) pre-evacuated at 383 K was determined with synchrotron X-ray powder diffraction measurement. Effective nanoporosity of the pre-evacuated CuBOTf was determined with N2 adsorption at 77 K. The experimental H2 and D2 adsorption isotherms of CuBOTf at 40 and 77 K were measured, being compared with quantum GCMC-simulated isotherms using the effective nanoporosity. The quantum-simulated H2 and D2 isotherms at 77 K using the Feynman-Hibbs effective potential coincided with the experimental ones. On the contrary, experimental H2 and D2 isotherms at 40 K had an explicit adsorption hysteresis, originating from the marked pore blocking effect on measuring the adsorption branch. The blocking effect for quantum H2 is more prominent than that for quantum D2; the selectivity for D2 over H2 at 40 K and 1 kPa was 5.8, being 1.5 times larger than that of single-walled carbon nanotube at least.