Atomically Dispersed Pd-O Species on CeO2(111) as Highly Active Sites for Low-Temperature CO Oxidation

Giulia Spezzati; Yaqiong Su; Jan P Hofmann; Angelica D Benavidez; Andrew T DeLaRiva; Jay McCabe; Abhaya K Datye; Emiel J M Hensen

doi:10.1021/acscatal.7b02001

Atomically Dispersed Pd-O Species on CeO₂(111) as Highly Active Sites for Low-Temperature CO Oxidation

ACS Catal. 2017 Oct 6;7(10):6887-6891. doi: 10.1021/acscatal.7b02001. Epub 2017 Sep 7.

Authors

Giulia Spezzati¹, Yaqiong Su¹, Jan P Hofmann¹, Angelica D Benavidez², Andrew T DeLaRiva², Jay McCabe², Abhaya K Datye², Emiel J M Hensen¹

Affiliations

¹ Laboratory of Inorganic Materials Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
² Department of Chemical & Biological Engineering and Center for Microengineered Materials, University of New Mexico, Albuquerque, New Mexico 87131, United States.

Abstract

Ceria-supported Pd is a promising heterogeneous catalyst for CO oxidation relevant to environmental cleanup reactions. Pd loaded onto a nanorod form of ceria exposing predominantly (111) facets is already active at 50 °C. Here we report a combination of CO-FTIR spectroscopy and theoretical calculations that allows assigning different forms of Pd on the CeO₂(111) surface during reaction conditions. Single Pd atoms stabilized in the form of PdO and PdO₂ in a CO/O₂ atmosphere participate in a catalytic cycle involving very low activation barriers for CO oxidation. The presence of single Pd atoms on the Pd/CeO₂-nanorod, corroborated by aberration-corrected TEM and CO-FTIR spectroscopy, is considered pivotal to its high CO oxidation activity.

Keywords: CO oxidation; FTIR; cerium oxide; computational modeling; mechanism; palladium; single site.