Abstract
The oxidation of Pd particles and subsequent reduction of PdO were studied in 0.2–0.7 bar O2and H2gas at 20–650 °C by in-situ transmission electron microscopy. The 15 nm thick Pd particles were 50–300 nm wide, and (111) oriented on the SiN support. Two oxidation mechanisms were observed: 1) the slow formation of epitaxial PdO at the Pd particle edges with orientations OR(1): PdO[201]//Pd[111] and PdO(020)//Pd{022}, 5.8° from OR(2): PdO[110]//Pd[100] and PdO[001]//Pd[001]. 2) the fast formation of randomly oriented PdO nucleating at the Pd particle edges. During the reduction process we observed epitaxial formation [OR(1) and OR(2)] as well as nonepitaxial formation of Pd (and Pd hydride). The formation of randomly oriented (5–10 nm) Pd particles on a (001) surface of PdO was much slower than of the epitaxial Pd grains on other PdO surfaces. A systematic study of the electron beam irradiation effect on the phase transformations showed that this effect can be avoided.
Original language | English |
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Pages (from-to) | 3094-3102 |
Number of pages | 9 |
Journal | European Journal of Inorganic Chemistry |
Volume | 2016 |
Issue number | 19 |
DOIs | |
Publication status | Published - 2016 |
Keywords
- Heterogeneous catalysis
- In-situ transmission electron microscopy
- Nanoparticles
- Oxidation
- Palladium
- Reduction