H → 31P, 31P → 1H, and 2H → 1H CP/MAS NMR Studies of the Large-Pore Gallophosphate Molecular Sieve Cloverite

Air-equilibrated cloverite containing normal and deuterated water was studied by 1 H, 31 P, and 71 Ga NMR with magic-angle spinning (MAS). The spectra are assigned, and the 1 H and 31 P spin−lattice relaxation and the kinetics of 1 H → 31 P, 31 P → 1 H, and 2 H → 1 H cross-polarization (CP) are examined in detail. Spin diffusion between the observed spins ( 1 H or 31 P) has a significant effect on the relative intensities of lines in the CP spectra. The results indicate that cloverite contains water-rich and water-deficient microdomains that contribute separately to the overall spectra. The water-rich microdomains contain defect P−OH groups created by the hydrolysis of the Ga−O−P bonds.