Low-temperature carbon monoxide oxidation catalysed by regenerable atomically dispersed palladium on alumina

Journal Article · Mon Sep 15 04:00:00 EDT 2014 · Nature Communications

DOI:https://doi.org/10.1038/ncomms5885· OSTI ID:1168917

Peterson, Eric J. ^[1]; DelaRiva, Andrew T. ^[1]; Lin, Sen ^[1]; Johnson, Ryan S. ^[1]; Guo, Hua ^[1]; Miller, Jeffrey T. ^[2]; Kwak, Ja Hun ^[3]; Peden, Charles H.F. ^[4]; Kiefer, Boris ^[5]; Allard, Lawrence F. ^[6]; Ribeiro, Fabio H. ^[7]; Datye, Abhaya K. ^[1]

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1. Univ. of New Mexico, Albuquerque, NM (United States)
2. Argonne National Lab. (ANL), Argonne, IL (United States)
3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); UNIST, Ulsan (Korea)
4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
5. New Mexico State Univ., Las Cruces, NM (United States)
6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
7. Purdue Univ., West Lafayette, IN (United States)

Catalysis by single isolated atoms of precious metals has attracted much recent interest since it promises the ultimate economy in atom efficiency. Previous reports have been confined to reducible oxide supports such as FeO_x, TiO₂ or CeO₂. Here we show that isolated Pd atoms can be stabilized on industrially relevant gamma-alumina supports. At low Pd loadings (≤0.5 wt%) these catalysts contain exclusively atomically dispersed Pd species. The addition of lanthanum-oxide to the alumina, long known for its ability to improve alumina stability, is found to also help in the stabilization of isolated Pd atoms. Aberration-corrected scanning transmission electron microscopy (AC-STEM) confirms the presence of intermingled Pd and La on the gamma-alumina surface. Operando X-ray absorption spectroscopy, performed on Pd/La-alumina and Pd/gamma-alumina (0.5 wt% Pd) demonstrates the presence of catalytically active atomically dispersed ionic Pd in the Pd/La-doped gamma-alumina system. CO oxidation reactivity measurements show onset of catalytic activity at 40 °C, indicating that the ionic Pd species are not poisoned by CO. The reaction order in CO and O₂ is positive, suggesting a reaction mechanism that is different from that on metallic Pd. The catalyst activity is lost if the Pd species are reduced to their metallic form, but the activity can be regenerated by oxidation at 700 °C in air. The high-temperature stability of these ionic Pd species on commercial alumina supports makes this catalyst system of potential interest for low-temperature exhaust treatment catalysts.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1168917
• Report Number(s): PNNL-SA--103304; 47582; KC0302010
• Journal Information: Nature Communications, Journal Name: Nature Communications Journal Issue: 52 Vol. 5; ISSN 2041-1723
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory