Catalyst–Support Interaction in Fluorinated Carbon-Supported Pt Catalysts for Reaction of NO with NH3

Catalysts comprising Pt supported on fluorinated carbon (0, 10, 28, and 65% F) have been characterized and their activities have been compared for reaction of NO with NH3. Both catalytic activity and selectivity to formation of N2 over FC-supported Pt catalysts vary with fluorine content. Activity and selectivity each increased with increasing F content to a maximum value at 28% F, then each deteriorated for Pt supported on FC with 65% F. Selectivity to N2 over FC-supported catalysts at temperatures below 200°C is superior to that at higher temperatures. XPS showed that Pt was situated at surface sites neighboring fluorinated carbons for FC having 0–28% F. However, Pt is enveloped in the support with 65% F. A positive shift of F 1s and a negative shift of Pt 4f binding energy were detected after Pt was deposited on the FC supports, indicating that electron charge transfer from F to Pt occurred on surfaces of FC-supported Pt catalysts. The increase in selectivity with FC-supported Pt catalysts is attributed to the electronic interaction between FC and Pt, which enhanced dissociative chemisorption of NO on active Pt sites.