2H-solid-state-NMR study of hydrogen adsorbed on catalytically active ruthenium coated mesoporous silica materials.
(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.
Institut für Physikalische und Theoretische Chemie, Freie Universität Berlin, Berlin, Germany.
Bernadeta
B
Walaszek
Xu
X
Yeping
Anna
A
Adamczyk
Hergen
H
Breitzke
Katrin
K
Pelzer
Hans-Heinrich
HH
Limbach
Jianlin
J
Huang
Hexing
H
Li
Gerd
G
Buntkowsky
D000327:Adsorption; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D016062:Porosity; D012428:Ruthenium / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
D012822:Silicon Dioxide; D012428:Ruthenium; D006859:Hydrogen