Hydrogen Utilization: Fuel Cells - Hydrogen Generation, Storage, and Utilization - page 162

(a) (b)

20 nm 5 nm

(c) (d)

11° 15°

16°

24°

2 nm

FIGURE 9.4 TEM (a) and HRTEM images (b,c), and SAED (d) of the Pt concave nanocubes recorded
along [001] direction. Source : Reproduced with permission from Lim et al. [50].

[51, 52]. For example, Chen's group designed and synthesized a new highly
durable iron phtalocyanine based nonprecious oxygen reduction reaction
(ORR) catalyst (Fe-SPc) for polymer electrolyte membrane fuel cells
(Fig. 9.6).
In 2010, Dai et al. synthesized nitrogen-doped graphene, and used it as a
metal-free electrode in alkaline fuel cells, which showed a much better elec-
trocatalytic activity, long-term operation stability, and tolerance to crossover
effect than platinum for oxygen reduction (Fig. 9.7).
Beside organometallic complexes and nitrogen-doped carbon-supported
metal ions, metal oxides or transition metal chalcogenides with high stability
may be considered as potential alternatives to traditional Pt-based cathode
catalysts.
Dai et al. in Stanford University reported a hybrid material consisting of
Co 3 O 4 nanocrystals grown on reduced grapheme oxide as a high performance
bi-fuctional catalyst for the oxygen reduction reaction and oxygen evolution