Cation Ordering and Exsolution in Copper-Containing Forms of the Flexible Zeolite Rho (Cu,M-Rho; M=H, Na) and Their Consequences for CO₂ Adsorption.

ABSTRACT: The flexibility of the zeolite Rho framework offers great potential for tunable molecular sieving. The fully copper-exchanged form of Rho and mixed Cu,H- and Cu,Na-forms have been prepared. EPR spectroscopy reveals that Cu²⁺ ions are present in the dehydrated forms and Rietveld refinement shows these prefer S6R sites, away from the d8r windows that control diffusion. Fully exchanged Cu-Rho remains in an open form upon dehydration, the d8r windows remain nearly circular and the occupancy of window sites is low, so that it adsorbs CO₂ rapidly at room temperature. Breakthrough tests with 10 % CO₂ /40 % CH₄ mixtures show that Cu_4.9 -Rho is able to produce pure methane, albeit with a relatively low capacity at this p_CO2 due to th

SUBMITTER: Lozinska MM 

PROVIDER: S-EPMC8518693 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature