Influence of Al Ions on the Reduction of Co3-xAlxO4: in situ XRD Investigation
Full article
| Общее |
Language:
Английский,
Genre:
Full article,
Status:
Published,
Source type:
Original
|
| Conference |
12th European Powder Diffraction Conference
27-30 Aug 2010
,
Darmstadt
|
| Journal |
Zeitschrift für Kristallographie
ISSN: 0044-2968
|
| Output data |
Year: 2011,
Number: 1,
Pages: 331-336
Pages count
: 6
DOI:
10.1524/zkpr.2011.0050
|
| Tags |
in situ X-ray diffraction, reduction, solid solution, domain structure |
| Authors |
Cherepanova S.
1,2
,
Bulavchenko O.
1,2
,
Simentsova I.
1
,
Gerasimov E.
1,2
,
Khassin A.
1
|
| Affiliations |
| 1 |
Boreskov Institute of Catalysis, Lavrentieva prospect 5, Novosibirsk, 630090, Russia
|
| 2 |
Novosibirsk State University, Pirogova street 2, Novosibirsk, 630090, Russia
|
|
The addition of small amounts of Al ions to nanocrystalline Co3O4 leads to con-siderable changes in its reduction. In situ XRD and TPR show that Al ions affect the extent of cobalt reduction achieved in a hydrogen flow. Co3O4 is fully reduced to metallic cobalt at a temperature of ca. 200 C. As for Al-modified samples Co3-xAlxO4 (x = 0.05, 0.1, 0.2), they contain CoO even after reduction at 350C. The higher is the Al content; the lower is the Co/CoO ratio. At 350 C, metallic particles in all cases consist of platelet domains having the hcp and fcc structure. In the case of metallic cobalt reduced from Co3O4, the fcc domains are twice thinner as compared to hcp ones, their average thicknesses being ca. 0.9 nm and 1.8 nm, respectively. In metallic cobalt reduced from Co3-xAlxO4 (x = 0.05, 0.1, 0.2), the fcc and hcp domains have almost equal average thicknesses of ca. 1.4 nm.