Tsuyohito Ito1,Kyotaro Takagi1,Moriyuki Kanno1,Hitoshi Muneoka1,Kazuo Terashima1
The University of Tokyo1
Tsuyohito Ito1,Kyotaro Takagi1,Moriyuki Kanno1,Hitoshi Muneoka1,Kazuo Terashima1
The University of Tokyo1
Non-equilibrium plasma can promote various reactions through the contributions of energetic/reactive species, such as electrons, ions, radicals, and photons, while avoiding the environmental temperature elevation. Although synergetic effects of such species are making most of plasma applications attractive, in some cases, the existence of an excessively diverse species prevent us from achieving desired controllability. As for the charged particles, there are several techniques for selectively extracting certain reactive species, mostly using electromagnetic field. However, it is still difficult to selectively extract reactive neutral species.<br/>One approach for separating neutral species from a gas mixture is by using sieves with microstructures [1] and metal-organic frameworks (MOFs) are attracting candidates for such sieves [2]. MOFs are porous materials composed of metal ions and organic ligands. By choosing the types of metal ions and ligands, it is possible to control pore structures, pore sizes, surface properties, morphology, and so on.<br/>Here, we are demonstrating H<sub>2</sub> extraction from low-temperature Ar/C<sub>3</sub>H<sub>8</sub> plasma by using zeolitic imidazolate framework-8 (ZIF-8) as a filter located in the plasma region. Quadrupole mass spectrometer was applied to analyze the atoms/molecules behind the ZIF-8 filter. By comparing with the no-filter case, it is indicated that ZIF-8 can selectively extract H<sub>2</sub> by impeding C<sub>3</sub>H<sub>8</sub> transfer, although it is not yet perfect. We have also confirmed that the ZIF-8 filters were not significantly damaged in the tested conditions. Further details will be presented at the symposium.<br/><br/>[1] L. M. Robeson, <i>The Upper Bound Revisited</i>, Journal of Membrane Science <b>320</b>, 390 (2008).<br/>[2] Q. Qian, P. A. Asinger, M. J. Lee, G. Han, K. Mizrahi Rodriguez, S. Lin, F. M. Benedetti, A. X. Wu, W. S. Chi, and Z. P. Smith, <i>MOF-Based Membranes for Gas Separations</i>, Chem. Rev. <b>120</b>, 8161 (2020).