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no barrier
OH
H + + e - ( U °)
U ° = 0.80 V
H + + e - ( U °)
U ° = 1.03 V
H + + e - ( U °)
U ° = 0.89 V
Co site too
crowded
H + + e - ( U °)
no barrier for
O 2 dissociation
U ° = 0.20 V
H + + e - ( U °)
U ° = 0.51 V
FIGURE 9.9 Top view of reduction pathways examined for the adsorbed O atoms on the partially
OH(ads)-covered (202) surface of Co 9 S 8 . Source : Reproduced with permission from Sidik and Anderson
[46]. (See color insert.)
retail infrastructure will not be available in the near future, car manufacturers
consider a liquid fuel as the best option for a short-term market introduction
of a fuel cell propulsion system [63]. Furthermore, the higher energy density
of a liquid fuel guarantees a driving range similar to that of internal combus-
tion engine vehicles [64]. The fuel favored by many car manufacturers is
methanol from which hydrogen can be produced onboard by SR [56]. The
reforming of the fuel, however, leads to slower response times, and extensive
gas clean-up procedures need to be carried out to supply the fuel cell with
high-grade hydrogen.
Some experts believe that fuel cell cars will never become economically
competitive with other technologies or that it will take decades for them to
become profitable [61, 65]. In July 2011, the Chairman and CEO of GM,
Daniel Akerson, stated that while the cost of hydrogen fuel cell cars is
decreasing: “The car is still too expensive and probably won't be practical
until the 2020-plus period, I don't know” [56]. In 2013, Lux Research, Inc.
issued a report that stated: “The dream of a hydrogen economy .  .  . is no
nearer”[57]. It concluded that “capital cost . . . will limit adoption to a mere
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