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Kyushu team develops multifunctional catalyst for poison-resistant hydrogen fuel cells; both H2 and CO as fuel

25 June 2017

Researchers at Kyushu University, Japan, have developed the first catalyst that can oxidize both hydrogen and carbon monoxide, depending on the pH of the reaction system. Carbon monoxide is a common pollutant in commercially available hydrogen gas but it poisons the platinum catalysts used in today’s fuel cells. A paper on the work appears in the journal Angewandte Chemie International Edition.

The new catalyst, based on a nickel-iridium [NiIr] complex, mimics the behavior of two enzymes: hydrogenase in acidic media (pH 4-7) and carbon monoxide dehydrogenase in basic media (pH 7-10). The team, led by Prof. Seiji Ogo, constructed a proof-of-concept fuel cell that turned the tables on carbon monoxide poisoning by using it as a fuel and generated energy from a 1:1 mixture of the two gases.

The researchers were able to isolate various intermediates in the oxidation processes to confirm the mechanisms of hydrogen and carbon monoxide oxidation by the catalyst.

We found that the catalyst reacted with hydrogen to form a hydride complex under acidic conditions. In addition, the catalyst readily coordinated with carbon monoxide, which was oxidized to carbon dioxide, under basic conditions.

—first author Professor Seiji Ogo

The team then investigated the resistance of the catalyst to poisoning by carbon monoxide in a prototype fuel cell using feed gases of hydrogen, carbon monoxide, and a 1:1 mixture of the two. The power density of the fuel cell containing the catalyst depended on the system pH and feed gas composition.

Oxidation of hydrogen by the catalyst was facilitated at low pH (acidic conditions) and oxidation of carbon monoxide was faster at high pH (basic conditions); these trends correspond well with the behavior observed for the related enzymes.

The ability of our catalyst to use both hydrogen and carbon monoxide as energy sources represents an important advance in hydrogen technology.

—Professor Ogo

The scientists anticipate that catalysts for hydrogen oxidation that can resist carbon monoxide poisoning will allow development of hydrogen fuels cells with improved performance.

Resources

  • Seiji Ogo, Yuki Mori, Tatsuya Ando, Takahiro Matsumoto, Takeshi Yatabe, Ki-Seok Yoon, Hideki Hayashi and Masashi Asano (2017) “One Model, Two Enzymes: Activation of Hydrogen and Carbon Monoxide” Angewandte Chemie International Edition doi: 10.1002/anie.201704864

June 25, 2017 in Catalysts, Fuel Cells, Hydrogen | Permalink | Comments (4)

Comments

It look brilliant but look twice. They didn't experiemced in a car so we don't know for the taxes we paid if it gonna improve cars or not. Notice that they are still negociating for other grants to keep there jobs indefinately with big paychecks for the forceable future.

After more than 100 years of paid researchs, we still drive 4 stroke gasoline/diesel cars and trucks with an ultra small proportion of limp costly battery cars. Both of these invention are more than a century old, LOL. If we read between the lines we discover that batteries and fuelcell are costly and do not last longer than an ice.

Believe me, buy a small econo box and keep it a very long time and cut subsidies toward scientific researchs because we pay them for nothing. Also there is only approx 40 bloggers here that are following these costly researchs. The results are this: no new discovery since the last 30 years with a trillion dollars budjet. All patents are sold to high financials banks that made them disappear and sjc and harvyd never noticed that. Im active also in YouTube blogs and i warned trump and pruitt to cut subsidies toward epa, doe and dot, nasa, etc.

If I read this right carbon is also present in hydrogen made from reforming fossil fuels and poisons the system and produces CO2 as part of the output. What else are they not telling us about H2. It's called lying by omission.

If the FC can tolerate a substantial amount of CO in its fuel, the purity requirements can be relaxed and it becomes cheaper.

If the FC can handle as much as 1:1 CO to H2, then it becomes attractive to use methanol as fuel and reform it on-board.  Methanol cracks thermally to 1:2 CO to H2.  There's always a "tail gas" in the FC, and with such a scheme its use becomes obvious:  it would be burned to heat the fuel reformer.

Doing a BOTE calculation and assuming Mirai-class fuel economy of ~60 miles per kg of H2-equivalent (500 moles of either H2 or CO) with 10% knocked off for reforming losses, I get about 99 grams/mile methanol consumption or about 30 MPG right on the nose at 30°C fuel temperature.  Considering that methanol is half oxygen by weight this is outstanding.

SOFCs are immune to CO, they use it as a fuel.
High Temperature PEMs are much more tolerant to CO.

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