Catalytic ignition of light hydrocarbons over Rh/Al2O3 studied in a stagnation-point flow reactor.

Abstract: The ignition (light-off) temperatures of catalytic oxidation reactions provide very useful information for understanding their surface reaction mechanism. In this study, the ignition behavior of the oxidation of hydrogen (H₂), carbon monoxide (CO), methane (CH₄), ethane (C₂H₆), and propane (C₃H₈) over Rh/alumina catalysts is examined in a stagnation-point flow reactor. The light-off temperatures are identified by means of the sudden increase of the catalyst temperature when linearly heating the catalyst for various fuel/oxygen ratios. For hydrogen and all hydrocarbons studied, the results show a rise of ignition temperature with increasing fuel/oxygen ratio, whereas the opposite trend is observed for the light-off of CO oxidation. Hydrogen oxidation, however, shows an opposite trend compared to previous investigations, performed on platinum [1,2]. [Copyright &y& Elsevier]