5.29.2 Argon Interaction with SnO 2
At variance as under air, in dry conditions, oxygen vacancies are formed, indicating
that the equilibrium
1=2O 2 þ V 0 $ O 0 is left-hand-shifted. Then, V 0 $ V 0
þ
þ e
À .
5.29.3 H 2 and CO Interaction with SnO 2 , in the Presence
of Air
The interaction with dry H 2 produces a very large number of V 0
þ . The effect,
higher than that seen in moist atmosphere, is due to the following reactions
H 2 $ 2H
Á
Sn Sn þ O 0 þ H
Á
$ HO À Sn Sn þ V 0
V 0 $ V 0
þ
þ e
À
(a)
(b)
Fig. 5.19 ESR spectra
recorded at 123 K of SnO 2
treated at 473 K under a wet
air stream and b wet argon
stream [17]
112
5 The Symmetry Properties Describe the Electronic Structure …
At variance as under air, in dry conditions, oxygen vacancies are formed, indicating
that the equilibrium
1=2O 2 þ V 0 $ O 0 is left-hand-shifted. Then, V 0 $ V 0
þ
þ e
À .
5.29.3 H 2 and CO Interaction with SnO 2 , in the Presence
of Air
The interaction with dry H 2 produces a very large number of V 0
þ . The effect,
higher than that seen in moist atmosphere, is due to the following reactions
H 2 $ 2H
Á
Sn Sn þ O 0 þ H
Á
$ HO À Sn Sn þ V 0
V 0 $ V 0
þ
þ e
À
(a)
(b)
Fig. 5.19 ESR spectra
recorded at 123 K of SnO 2
treated at 473 K under a wet
air stream and b wet argon
stream [17]
112
5 The Symmetry Properties Describe the Electronic Structure …