| Autor: |
Tankard RE; Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. ibchork@fysik.dtu.dk., Romeggio F; Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. ibchork@fysik.dtu.dk., Akazawa SK; Center for Visualizing Catalytic Processes (VISION), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark., Krabbe A; Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. ibchork@fysik.dtu.dk., Sloth OF; Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. ibchork@fysik.dtu.dk., Secher NM; Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. ibchork@fysik.dtu.dk., Colding-Fagerholt S; Center for Visualizing Catalytic Processes (VISION), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark., Helveg S; Center for Visualizing Catalytic Processes (VISION), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark., Palmer R; Nanomaterials Lab, Swansea University, Bay Campus, Swansea, UK., Damsgaard CD; Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. ibchork@fysik.dtu.dk.; Center for Visualizing Catalytic Processes (VISION), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.; National Centre for Nano Fabrication and Characterization, Technical University of Denmark, 2800 Kongens Lyngby, Denmark., Kibsgaard J; Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. ibchork@fysik.dtu.dk.; Center for Visualizing Catalytic Processes (VISION), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark., Chorkendorff I; Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. ibchork@fysik.dtu.dk. |
| Abstrakt: |
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 AuTiO x alloy nanoparticles for CO oxidation compared with pure Au nanoparticles on TiO 2 . 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 TiO 2 -coated micro-reactors for thermocatalytic activity measurements of CO oxidation. The AuTiO x nanoparticles exhibited improved stability at elevated temperatures, which is attributed to a self-anchoring interaction with the TiO 2 substrate. The structure of the AuTiO x 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 AuTiO x 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 TiO 2 substrates, and highlights the importance of complementary characterization techniques to investigate and optimize nanoparticle catalyst designs of this nature. |
