Low Temperature CO Oxidation Reactivity on Atomically Dispersed Palladium on Alumina

Abhaya K.  Datye, University of New Mexico

The efficient use of precious metals as catalysts requires small particle size, with the ultimate efficiency being achieved with isolated single atoms on a high surface area support. There are previous reports of water gas shift and CO oxidation reactions being catalyzed by ionic forms of transition metals, but generally on reducible supports such as CeO2, TiO2 or FeOx. But most commercial catalysts are based on high surface area, non-reducible supports. In previous work on Pd/alumina and Pd/La-alumina [1], we found that the La-alumina support provided higher CO oxidation activity at low temperatures. The samples appeared to contain isolated single atoms of Pd. To explore the reactivity of these isolated single atoms we have synthesized Pd catalysts with low metal loading, so as to avoid formation of large metallic particles. The addition of La-oxide to the catalyst/support system, long known for its promoter effects, is found to stabilize the Pd single atoms. Aberration-corrected scanning transmission electron microscopy (AC-STEM) confirms the presence of intermingled Pd and La on the gamma-alumina surface [2]. This talk will describe our work on understanding these atomically dispersed species on industrially relevant heterogeneous catalysts.

References
[1] J.R. Gaudet et al. ACS Catal., 3, 846 (2013). DOI 10.1021/cs400024u
[2] E.J. Peterson et al. Nat Commun, 5 (2014). DOI: 10.1038/ncomms5885