Multiple-pulse 1H nuclear magnetic resonance investigations of titania and ruthenium dispersed on titania

Abstract

¹ H NMR spectra of Ru/TiO₂ and TiO₂ consist of sharp and broad resonances associated with the oxide support and hydrogen chemisorbed on ruthenium particles. The cause of the line broadening has been investigated using pulsed NMR techniques. Line-narrowing is not observed for these samples under multiple pulse (MREV8) decoupling. Selective excitation (DANTE) of the TiO₂¹H NMR spectrum shows that the linewidth arises from a distribution of chemical shifts and not from static homonuclear ¹H dipolar coupling at 370 K. The ¹H NMR results imply that the hydrogen species in these catalyst systems are labile on the NMR spectral timescale.