Au nanoparticles represent the most remarkable example of a size effect in heterogeneous catalysis. However, a major issue hindering the use of Au nanoparticles in technological applications is their rapid sintering. We explore the potential of stabilizing Au nanoclusters on SiO2by alloying them with a reactive metal, Ti. Mass-selected Au/Ti clusters (400000 amu) and Au2057clusters (405229 amu) were produced with a magnetron sputtering, gas condensation cluster beam source in conjunction with a lateral time-of-flight mass filter, deposited onto a silica support and characterised by XPS and LEIS. The sintering dynamics of mass-selected Au and Au/Ti alloy nanoclusters were investigated in real space and real time with atomic resolution aberration-corrected HAADF-STEM imaging, supported by model DFT calculations. A strong anchoring effect was revealed in the case of the Au/Ti clusters, because of a much increased local interaction with the support (by a factor 5 in the simulations), which strongly inhibits sintering, especially when the clusters are more than ∼0.60 nm apart. Heating the clusters at 100 °C for 1 h in a mixture of O2and CO, to simulate CO oxidation conditions, led to some segregation in the Au/Ti clusters, but in line with the model computational investigation, Au atoms were still present on the surface. Thus size-selected, deposited nanoalloy Au/Ti clusters appear to be promising candidates for sustainable gold-based nanocatalysis.

Niu, Y., Schlexer, P., Sebok, B., Chorkendorff, I., Pacchioni, G., Palmer, R. (2018). Reduced sintering of mass-selected Au clusters on SiO2by alloying with Ti: An aberration-corrected STEM and computational study. NANOSCALE, 10(5), 2363-2370 [10.1039/c7nr06323g].

Reduced sintering of mass-selected Au clusters on SiO2by alloying with Ti: An aberration-corrected STEM and computational study

Schlexer, Philomena;Pacchioni, Gianfranco;
2018

Abstract

Au nanoparticles represent the most remarkable example of a size effect in heterogeneous catalysis. However, a major issue hindering the use of Au nanoparticles in technological applications is their rapid sintering. We explore the potential of stabilizing Au nanoclusters on SiO2by alloying them with a reactive metal, Ti. Mass-selected Au/Ti clusters (400000 amu) and Au2057clusters (405229 amu) were produced with a magnetron sputtering, gas condensation cluster beam source in conjunction with a lateral time-of-flight mass filter, deposited onto a silica support and characterised by XPS and LEIS. The sintering dynamics of mass-selected Au and Au/Ti alloy nanoclusters were investigated in real space and real time with atomic resolution aberration-corrected HAADF-STEM imaging, supported by model DFT calculations. A strong anchoring effect was revealed in the case of the Au/Ti clusters, because of a much increased local interaction with the support (by a factor 5 in the simulations), which strongly inhibits sintering, especially when the clusters are more than ∼0.60 nm apart. Heating the clusters at 100 °C for 1 h in a mixture of O2and CO, to simulate CO oxidation conditions, led to some segregation in the Au/Ti clusters, but in line with the model computational investigation, Au atoms were still present on the surface. Thus size-selected, deposited nanoalloy Au/Ti clusters appear to be promising candidates for sustainable gold-based nanocatalysis.
Articolo in rivista - Articolo scientifico
Materials Science (all)
English
2018
10
5
2363
2370
none
Niu, Y., Schlexer, P., Sebok, B., Chorkendorff, I., Pacchioni, G., Palmer, R. (2018). Reduced sintering of mass-selected Au clusters on SiO2by alloying with Ti: An aberration-corrected STEM and computational study. NANOSCALE, 10(5), 2363-2370 [10.1039/c7nr06323g].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/212297
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