INFRARED STUDY OF THE DECOMPOSITION OF CARBON SUBOXIDE OVER SUPPORTEDRHODIUM

Infrared spectroscopy has been employed to monitor the decomposition o f carbon suboxide (C3O2) over Rh/Al2O3 films. Direct decomposition of C3O2 over 2.2% Rh/Al2O3 at 298 K led to the production of the rhodium- gem-dicarbonyl species and adsorbed C2O on the support; the latter spe cies could be removed by extended evacuation at 298 K. Upon introducti on of dihydrogen and heating to 373-423 K, a rhodium carbonyl hydride species was detected. Further heating to 493 K led to the production o f methane and carbon dioxide. It has been demonstrated using C-13-labe led C3O2 that the methane resulted from both atomic carbon generated f rom direct decomposition of C3O2 and from active carbon produced from decomposition of the carbonyl hydride surface species.