3
62
DELANNOY ET AL.
In conclusion, it seems obvious that modifying the ac-
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9
tivation of tungsten carbide by changing the surface car-
bide stoichiometry converts the catalytic properties of WC
into either metallic or acid–base ones and subsequently its
selectivity toward the formation of pentafluoroethane or
alkanes and unsaturated by-products. More generally, this
work provides evidence of a relationship between the mode
of activation and the catalytic properties of tungsten car-
bides; the acid–base character seems to increase with the
extent of decarburization of the surface. It is obvious that
1
1
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1978).
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