Stable mass-selected AuTiOx nanoparticles for CO oxidation

Rikke Egeberg Tankard, Filippo Romeggio, Stefan Kei Akazawa, Alexander Krabbe, Olivia Fjord Sloth, Niklas Mørch Secher, Sofie Colding-Fagerholt, Stig Helveg, Richard Palmer, Christian Danvad Damsgaard, Jakob Kibsgaard, Ib Chorkendorff*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Stability under reactive conditions poses a common challenge for cluster- and nanoparticle-based catalysts. Since the catalytic properties of <5 nm gold nanoparticles were first uncovered, optimizing their stability at elevated temperatures for CO oxidation has been a central theme. Here we report direct observations of improved stability of AuTiOx alloy nanoparticles for CO oxidation compared with pure Au nanoparticles on TiO2. The nanoparticles were synthesized using a magnetron sputtering, gas-phase aggregation cluster source, size-selected using a lateral time-of-flight mass filter and deposited onto TiO2-coated micro-reactors for thermocatalytic activity measurements of CO oxidation. The AuTiOx nanoparticles exhibited improved stability at elevated temperatures, which is attributed to a self-anchoring interaction with the TiO2 substrate. The structure of the AuTiOx nanoparticles was also investigated in detail using ion scattering spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The measurements showed that the alloyed nanoparticles exhibited a core-shell structure with an Au core surrounded by an AuTiOx shell. The structure of these alloy nanoparticles appeared stable even at temperatures up to 320 °C under reactive conditions, for more than 140 hours. The work presented confirms the possibility of tuning catalytic activity and stability via nanoparticle alloying and self-anchoring on TiO2 substrates, and highlights the importance of complementary characterization techniques to investigate and optimize nanoparticle catalyst designs of this nature.

Original languageEnglish
JournalPhysical Chemistry Chemical Physics
Pages (from-to)9253–9263
Publication statusPublished - 2024


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