Open AccessCharacterization of a Spent Ru/C Catalyst after Gasification of Biomass in Supercritical Water
Author(s) -
J. Wambach,
M. Schubert,
M. Döbeli,
Frédéric Vogel
Publication year - 2012
Publication title -
chimia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.387
H-Index - 55
eISSN - 2673-2424
pISSN - 0009-4293
DOI - 10.2533/chimia.2012.706
Subject(s) - ruthenium , catalysis , supercritical fluid , leaching (pedology) , chemical engineering , materials science , corrosion , alloy , metal , x ray photoelectron spectroscopy , aqueous solution , carbon fibers , titanium , inorganic chemistry , chemistry , metallurgy , organic chemistry , composite material , environmental science , composite number , soil science , engineering , soil water
Carbon-supported ruthenium catalysts promote the gasification of aqueous organic feed with high efficiency to synthetic natural gas in supercritical water. Ruthenium metal was recently identified as the catalytically active species. [1] Occasionally deactivation is observed. To understand the deactivation, the fresh and several spent catalyst samples were investigated by RBS, ERDA, and XPS. The data revealed a massive reduction of the ruthenium concentration in toto and especially of the surface concentration. Of importance is the almost complete disappearance of the spectral features in the valance band region. Coverage of the ruthenium clusters e.g. with a thin 'carbonaceous' layer, i.e. a kind of fouling, or structural modifications of the ruthenium clusters might be the origin. Additionally, leaching of ruthenium might contribute, but is not considered a major effect, because ruthenium was never found in the liquid effluent of the reactor. The influence of additionally detected corrosion products (Ni, Cr, Fe, Ti) from the stainless steel and the titanium alloy walls seems to be small. No evidence for a deactivation by sulphur could be found.