2H-solid-state-NMR study of hydrogen adsorbed on catalytically active ruthenium coated mesoporous silica materials

Solid State Nucl Magn Reson. 2009 Jun;35(3):164-71. doi: 10.1016/j.ssnmr.2009.02.006. Epub 2009 Mar 13.

Abstract

(2)H solid-state NMR measurements were performed on three samples of ruthenium nanoparticles synthesized inside two different kinds of mesoporous silica, namely SBA-3 silica materials and SBA-15 functionalized with -COOH groups and loaded with deuterium gas. The line-shape analyses of the spectra reveal the different deuteron species. In all samples a strong -OD signal is found, which shows the catalytic activity of the metal, which activates the D-D bond and deuterates the -SiOH groups through the gas phase, corroborating their usability as catalysts for hydrogenation reactions. At room temperature the mobility of the -Si-OD groups depends on the sample preparation. In addition to the -Si-OD deuterons, the presence of different types of deuterons bound to the metal is revealed. The singly coordinated -Ru-D species exhibit several different quadrupolar couplings, which indicate the presence of several non-equivalent binding sites with differing binding strength. In addition to the dissociated hydrogen species there is also a dihydrogen species -Ru-D(2), which is attributed to defect sites on the surface. It exhibits a fast rotational dynamics at all temperatures. Finally there are also indications of three-fold coordinated surface deuterons and octahedrally coordinated deuterons inside the metal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Catalysis
  • Hydrogen / chemistry*
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Conformation
  • Porosity
  • Ruthenium / chemistry*
  • Silicon Dioxide / chemistry*

Substances

  • Silicon Dioxide
  • Ruthenium
  • Hydrogen