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New Stable and CO-Tolerant Catalyst for PEM Fuel Cells
25 July 2010
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| Polarization curves for H2 oxidation on different catalysts in the presence of 2% CO at room temperature. The new Pt/titanium tungsten oxide catalyst is in blue. Credit: ACS, Wang et al. Click to enlarge. |
A team at Cornell University has developed a new highly stable and CO-tolerant platinum/titanium tungsten oxide anode (Pt/Ti0.7W0.3O2) electrocatalyst for PEM fuel cells. A paper on their work was published online 12 July in the Journal of the American Chemical Society.
Among the challenges facing the commercialization of fuel cells for automotive and portable electronics applications is the development of inexpensive, durable and efficient catalysts for hydrogen oxidation. Platinum is currently the catalyst of choice, but is easily “poisoned” by low levels of CO (10 ppm), resulting in a significant degradation in performance.
Other research has shown that platinized metal oxides—especially those of tungsten—exhibit increased CO tolerance. However, tungsten suffers from low electronic conductivity.
To address that issue, the Cornell team, led by Dr. Hector Abruña, turned to titania (TiO2), which been used as a catalyst support in fuel cells duel to its stability, even though its own electronic conductivity is much lower than that of conventional carbon supports. The conductivity of titania, the team noted, can be improved by aleovalent cation substitution.
The Cornell team synthesized nanoparticles of Pt supported on conducting Ti0.7W0.3O2.
Initial tests indicated that Pt/Ti0.7W0.3O2 is more stable than Pt/C and PtRu/C catalysts. After 500 cycles, the loss in the integrated Coulombic charge of the CV for the new catalyst was only 5%, while it was more than 30% in the case of a commercial E-TEK PtRu/C catalyst.
The new material also exhibited high activity for H2 oxidation as well as a higher CO tolerance than Pt/C and PtRu/C catalysts.
This work was supported by the US Department of Energy (DOE) and by the Energy Materials Center at Cornell, an Energy Frontier Research Center funded by DOE Office of Basic Energy Sciences. The authors acknowledged helpful discussions with General Motors Fuel Cell Activities.
(A hat-tip to David!)
Resources
Deli Wang, Chinmayee V. Subban, Hongsen Wang, Eric Rus, Francis J. DiSalvo and Hector D. Abruña (2010) Highly Stable and CO-Tolerant Pt/Ti0.7W0.3O2 Electrocatalyst for Proton-Exchange Membrane Fuel Cells. J. Am. Chem. Soc., Article ASAP doi: 10.1021/ja102931d
July 25, 2010 in Catalysts, Fuel Cells, Hydrogen | Permalink | Comments (6) | TrackBack (0)
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Could become an interesting improvement in future FC tolerance, durability and performance. Would it drive mas production cost down?
Posted by: HarveyD | July 25, 2010 at 09:39 AM
The higher temperature PEMs are also more tolerant of CO. I read that a major cost is not the platinum but the membranes. When you need hundreds of cells you need hundreds of membranes. The balance of system is lower cost with higher temperature PEMs as well. They will find a good combination that could even be used in home CHP and then they can drive the costs down.
Posted by: SJC | July 25, 2010 at 10:18 AM
SOFC does a good job for home use, and weight and temperature constraints are relaxed.
Posted by: Davemart | July 25, 2010 at 10:57 AM
Either would make good home CHP units. HTPEM runs at over 200f, which would provide water heating, home heating and single stage absorption cooling. All you need is a good natural gas to H2 reformer and the stack does not require ultra low CO levels.
The idea of perfecting and cost reducing fuel cells for homes and business has a positive outlook. If you can build 3-5 kW stacks for homes, you can build 30-50 kW stacks for buildings and then you are not far from reforming biomethanol on vehicle for propulsion.
Posted by: SJC | July 25, 2010 at 11:53 AM
Dedicated home energy supplies have to compete against existing electrical energy networks. In many places, (like in our area) we have invested into much lower cost (as low as 2 cents/Kwh) Hydro plants and dedicated home power units would have a hard to match such low cost. However, in many other places, where e-energy cost as much as 15 to 25 cents/Kwh it could be another story. Also, in countries or areas already in short supply, dedicated home supplies could be a good solution.
Posted by: HarveyD | July 26, 2010 at 08:44 AM
Not so much "dedicated" but assisting. If you can get the peak load on summer days distributed on the grid, you can save a lot and provide more stable power. Combine that with the benefits of CHP with cooling and you just might have a winner in many parts of the U.S.
Posted by: SJC | July 26, 2010 at 10:35 AM