The single-component adsorption of C2H4 and C2H6 was evaluated at 298 K for various SAPO-RHO samples, including Li-SAPO-RHOs, H-SAPO-RHO, and M-SAPO-RHOs (M = Na + , K + , or Cs + ) (Fig. and figs. S16 and S17). Using the adsorption capacity of H-SAPO-RHO at 1 bar as a reference, we observed a decrease in adsorption capacity for both C2H4 and C2H6 as cation radius increased (table ).