Anion-Doping-Mediated Metal–Support Interactions in CeO<sub>2</sub>-Supported Pd Catalysts for CO<sub>2</sub> Hydrogenation
Luyang Qiao, Xi-guang Wang, Shanshan Zong, Zhi-Shen Huang, Zhangfeng Zhou, Maohong Fan, Yuan‐Gen Yao
Abstract
The electronic and geometric robustness of active sites in catalysts determines their long-term efficiency in CO 2 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 CeO 2 by doping chlorine anions into the CeO 2 lattice. The developed Pd@CeOCl/CeO 2 catalyst exhibits sustainable activity (3150 mmol·g Pd –1 ·h –1 ) and CO selectivity (99.7%) for at least 200 h, as well as enhanced resistance toward CO and H 2 O. Anion-doping-mediated SMSIs result in significant electronic perturbations in the Pd δ+ –[Cl–Ce–O] δ− interface, which modulates the surface properties and the energy band of the catalyst. Combined spectroscopic and microscopic evidence unveils that a Cl δ− –Cl – pair buffers the electron transfer in Pd δ+ ↔Pd 0 and Ce 4+ ↔Ce 3+ cycles, which circumvents the further hydrogenation of CO and shields Pd δ+ sites from sintering in hydrogenation conditions.