In situ XAFS analysis system for high-pressure catalytic reactions and its application to CO₂ hydrogenation over a Rh/Y-zeolite catalyst

An in situ XAFS cell was developed and used for the structural analysis of a Rh ion-exchanged zeolite catalyst during high-pressure hydrogenation of carbon dioxide. The in situ cell enabled analyses of the catalyst structures that changed with the reaction atmosphere and elapsed time; the peak assigned to Rh-O scattering changed to that assigned to Rh-Rh scattering at 404 K during the pretreatment by hydrogen. After 30 min of the carbon dioxide hydrogenation reaction, the peak intensity assigned to Rh-Rh scattering increased corresponding to the increase in the catalytic activity.