Presentation Information
[2E04]Electronic states and surface chemistry on the Pd/Cu single atom alloy model catalyst studied by synchrotron radiation XPS
*Wataru Osada1 (1. National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology)
Single atom alloy catalysts (SAACs) have attracted considerable attention as a new class of heterogeneous catalysts. On a Pd/Cu SAAC, the spillover mechanism accounts for the high activity and selectivity. In this presentation, I will discuss the surface chemical processes of hydrogen, formic acid, and CO2 on a Pd/Cu SAA model catalyst.Hydrogen dissociation and spillover were directly observed by IRAS and SR-XPS. DFT calculations indicated indirect charge transfer from Pd to H through the Cu substrate. A similar charge transfer to monodentate formate was also observed during formic acid decomposition. Formate species were found to be adsorbed preferentially on Cu rather than Pd, implying an advantage of Pd/Cu SAACs in methanol synthesis. This hypothesis was demonstrated by AP-XPS measurements, which showed CO2 hydrogenation to formate and methoxy species even at room temperature. Moreover, the role of carbonate species as reactive intermediates was proposed.