“…The functionalization of MEA-M4 was not complete (Osuna et al, 2020) and the presence of sodium in the interlayer produced different environments in the organic cation. The 13 C MAS NMR spectra of X-MEA-M4 showed the same set of signals as the initial functionalized mica, but with different relative intensities due to the loss of the organic cation during the adsorption (Fig.…”