135
Tian et al. reported a class of core-shell electrocatalysts with well-dispersed
inexpensive titanium nitrite nanoparticle cores and platinum layer shells [41]. The
optimized Ti 0.9 Cu 0.1 N@Pt/NCNT has a Pt mass activity 5 times higher than commercial Pt/C. These authors used titanium nickel binary nitrate as a core and placed
several layers of Pt on them. Both activity and stability of this catalyst outperformed
commercial Pt/C.
8.2 Hydrogen Oxidation Reaction on Pt Monolayer
Electrocatalysts and CO Tolerance
Hydrogen oxidation/reduction on Pt is one of the fastest electrochemical reactions.
For its use in fuel cells for energy conversion there is no problems with Pt catalysts
in acid solutions. In alkaline solutions, the reaction is considerably slower; the
exchange current density is lower by two orders of magnitude. Thus, a considerable
interest exists for it. In acid solutions, if hydrogen is not very clean, but contains
small amounts of CO, poisoning is a difficult problem. The reformate, obtained by
the reforming of ethanol, methanol, or gasoline, contains small amounts of CO,
which is very difficult to remove. A concentration as low as 10 ppm is sufficient to
poison the Pt sites and block the surface for the hydrogen oxidation reaction (HOR).
For such fuels, the Pt catalysts have to have a good CO tolerance. This means that it
has to oxidize a certain amount of CO and tolerate the rest.
A submonolayer of Pt deposited on Ru nanoparticles by galvanic displacement
has excellent CO tolerance in H 2 oxidation. In the other class of nanocatalysts, coreshell-structured PdAuM (M = Co, Fe, Ni) nanoparticles served as substrates for
Pt ML , and an enhancement in activity and reduction in cost were successfully
achieved. These findings can be applied in designing practical nanoparticle catalysts,
new catalysts for alcohol, and other organic oxidation at low Pt content, high
efficiency, and reduced costs by using supported Pt monolayers and other core-sell
structures.
Figure 8.24 show rotating disk measurements of CO tolerance of PtRu 20 catalyst
for H 2 oxidation compared with the best commercial Pt 2 Ru 3 electrocatalyst in
1000 ppm of CO in H 2 , at 60 C. Much larger currents are maintained with PtRu 20
electrocatalyst.
8.3 Methanol Oxidation on Platinum Monolayer
Electrocatalysts
Liquid fuels, especially methanol and ethanol, are considered as potential alternatives to hydrogen fuel in PEMFCs due to their high energy density, likely production from renewable sources, and the ease of their storage and transportation.
8.3 Methanol Oxidation on Platinum Monolayer Electrocatalysts
Tian et al. reported a class of core-shell electrocatalysts with well-dispersed
inexpensive titanium nitrite nanoparticle cores and platinum layer shells [41]. The
optimized Ti 0.9 Cu 0.1 N@Pt/NCNT has a Pt mass activity 5 times higher than commercial Pt/C. These authors used titanium nickel binary nitrate as a core and placed
several layers of Pt on them. Both activity and stability of this catalyst outperformed
commercial Pt/C.
8.2 Hydrogen Oxidation Reaction on Pt Monolayer
Electrocatalysts and CO Tolerance
Hydrogen oxidation/reduction on Pt is one of the fastest electrochemical reactions.
For its use in fuel cells for energy conversion there is no problems with Pt catalysts
in acid solutions. In alkaline solutions, the reaction is considerably slower; the
exchange current density is lower by two orders of magnitude. Thus, a considerable
interest exists for it. In acid solutions, if hydrogen is not very clean, but contains
small amounts of CO, poisoning is a difficult problem. The reformate, obtained by
the reforming of ethanol, methanol, or gasoline, contains small amounts of CO,
which is very difficult to remove. A concentration as low as 10 ppm is sufficient to
poison the Pt sites and block the surface for the hydrogen oxidation reaction (HOR).
For such fuels, the Pt catalysts have to have a good CO tolerance. This means that it
has to oxidize a certain amount of CO and tolerate the rest.
A submonolayer of Pt deposited on Ru nanoparticles by galvanic displacement
has excellent CO tolerance in H 2 oxidation. In the other class of nanocatalysts, coreshell-structured PdAuM (M = Co, Fe, Ni) nanoparticles served as substrates for
Pt ML , and an enhancement in activity and reduction in cost were successfully
achieved. These findings can be applied in designing practical nanoparticle catalysts,
new catalysts for alcohol, and other organic oxidation at low Pt content, high
efficiency, and reduced costs by using supported Pt monolayers and other core-sell
structures.
Figure 8.24 show rotating disk measurements of CO tolerance of PtRu 20 catalyst
for H 2 oxidation compared with the best commercial Pt 2 Ru 3 electrocatalyst in
1000 ppm of CO in H 2 , at 60 C. Much larger currents are maintained with PtRu 20
electrocatalyst.
8.3 Methanol Oxidation on Platinum Monolayer
Electrocatalysts
Liquid fuels, especially methanol and ethanol, are considered as potential alternatives to hydrogen fuel in PEMFCs due to their high energy density, likely production from renewable sources, and the ease of their storage and transportation.
8.3 Methanol Oxidation on Platinum Monolayer Electrocatalysts