“…There are numerous oligomeric cations that could be used as pillars, as well as Al, Zr, Ti, Cr, Fe, Ce and others [ 1 , 3 , 4 ]. These cations could be used individually [ 2 , 5 , 6 , 7 , 8 ] or mixed [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”