Anion-Doping-Mediated Metal-Support Interactions in CeO2-Supported Pd Catalysts for CO2 Hydrogenation

The electronic and geometric robustness of active sites in catalysts determines their long-term efficiency in CO2 hydrogenation. One effective strategy to improve durability is rationalizing metal site charge distribution through strong metal-support interactions (SMSIs). We propose an effective approach that can modulate the SMSI between Pd and CeO2 by doping chlorine anions into the CeO2 lattice. The developed Pd@CeOCl/CeO2 catalyst exhibits sustainable activity (3150 mmol<middle dot>g(Pd)(-1)<middle dot>h(-1)) and CO selectivity (99.7%) for at least 200 h, as well as enhanced resistance toward CO and H2O. Anion-doping-mediated SMSIs result in significant electronic perturbations in the Pd delta+-[Cl-Ce-O](delta-) interface, which modulates the surface properties and the energy band of the catalyst. Combined spectroscopic and microscopic evidence unveils that a Cl delta--Cl- pair buffers the electron transfer in Pd delta+<-> Pd-0 and Ce4+<-> Ce3+ cycles, which circumvents the further hydrogenation of CO and shields Pd delta+ sites from sintering in hydrogenation conditions.