Table 1 Parameters of local structure around Co atoms obtained from curve-fitting of the Co K-edge EXAFS. N is the coordination number.

From: Dramatic band gap reduction incurred by dopant coordination rearrangement in Co-doped nanocrystals of CeO2

Sample

Bond

N

R (Å)

σ2 (10−3 Å2)

ΔE 0 (eV)

As-grown

Co - O

5.7 ± 0.1

2.06 ± 0.01

7.6 ± 0.3

−1.9 ± 0.5

Co – Ce

2.9 ± 0.4

3.79 ± 0.01

8.1 ± 1.3

−10.1 ± 1.0

200 °C

Co - O

0.5 ± 0.1

1.86

1.3 ± 0.5

−9.1 ± 5.0

Co - O

4.1 ± 0.2

2.06

6.1 ± 0.8

−2.7 ± 0.5

300 °C

Co - O

1.0 ± 0.1

1.86

5.5 ± 2.3

−10.4 ± 5.0

Co - O

2.4 ± 0.2

2.06

6.4 ± 1.3

−3.5 ± 0.5

400°C

Co - O

1.3 ± 0.1

1.86

6.6 ± 0.5

−7.8 ± 0.5

Co – O

2.0 ± 0.1

2.06

7.9 ± 0.6

−3.8 ± 0.5

Co - Ce

1.6 ± 0.2

3.23 ± 0.01

13.9 ± 1.6

−2.0 ± 1.3

500 °C

Co - O

1.5 ± 0.1

1.86

4.2 ± 2.5

−10.2 ± 0.5

Co – O

1.3 ± 0.1

2.06

3.9 ± 1.3

−2.9 ± 2.5

Co - Ce

1.2 ± 0.2

3.25 ± 0.02

9.8 ± 2.5

−2.0 ± 1.3

600 °C

Co - O

3.9 ± 0.3

1.87 ± 0.01

13.3 ± 1.4

−9.7 ± 5.0

Co – Ce

1.3 ± 0.4

3.22 ± 0.02

7.8 ± 2.9

−5.5 ± 5.0

650 °C

Co - O

3.9 ± 0.3

1.86 ± 0.01

10.1 ± 1.1

−8.1 ± 5.0

Co – Ce

1.4 ± 0.4

3.21 ± 0.02

6.9 ± 3.0

−8.3 ± 5.0

  1. R is the bond length. σ2 is the Debye-Waller-like factor serving as a measure of local disorder. ΔE0 is the difference between the zero kinetic energy value of the sample and that of the theoretical model used in FEFF. Uncertainties were estimated by the double-minimum residue (2χ2) method.
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