“…The acid site type, quantity, and accessibility in 2D MFI zeolites have been measured by different techniques, including the FTIR of adsorbed small and bulky organic base molecules, organic base uptake measurement by GC/MS instruments, and 31 P MAS NMR spectra (Table 11). For example, the FTIR spectra of adsorbed pyridine, collidine, and DTBP molecules have shown that the 2D unilamellar and multilamellar MFI zeolites have a higher fraction of Lewis acidity than that of 3D MFI, while the accessibility of acid sites is improved due to the open structure [247][248][249][250]. The acid site accessibility of pillared MFI and SPP zeolites has been measured by direct DTBP uptake measurements, which maintain the characteristics of the high acid site accessibility in 2D MFI zeolites [173,245,251,252].…”