Appeal 2007-0128
Reexamination Control 90/006,208
Patent 5,573,648
proton conductor be a copolymer having a tetrafluoroethylene backbone with a
side
chain of perfluorinated monomers containing at least one sulfonic acid group.
Atwood claim 16 depends from claim 14 and requires that one of the first and
second conductor materials is 50-99 wt% carbon black and the other is 1-50 wt%
platinum. Atwood states that no combination of references discloses the claimed
gas sensor having such electrodes. (Appeal Br., p. 44-45 and 50-51).
As discussed above, Grot teaches the formation of an electrode from
NAFION7 and a catalyst having 20% platinum on a VULCAN7 carbon support.
(Grot, col. 14, ll. 15-27). Grot also teaches that electrodes may be formed from
electroconductive oxides. (Grot, col. 4, ll. 56-61). Similarly, Uchida teaches that
its electrodes contain at least a noble metal catalyst, a carbon powder and a solid
polymer electrolyte. (Uchida, col. 3, lines 46-56). Also, Vanderborgh describes
forming its electrodes with a mixture of platinum or any other suitable
electrocatalyst dispersed and supported on carbon black and further describes
NAFION7 as a suitable binder for electrodes. (Vanderborgh, col. 3, ll. 11-14 and
col. 8, ll. 13-25).
One of ordinary skill in the art would have been motivated to form sensing
and counter electrodes with carbon black and noble metals or metal oxides as
Dempsey describes electrodes formed from noble metals and as Grot, Uchida and
Vanderborgh teach that suitable electrodes for gas sensing applications may be
formed with carbon and any suitable electroconductive material, such as noble
41
Page: Previous 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Next
Last modified: September 9, 2013