A long-lived catalyst facilitates the first steps toward small-scale hydrogen generator

November 5, 2014, Agency for Science, Technology and Research (A*STAR), Singapore
A long-lived catalyst facilitates the first steps toward small-scale hydrogen generator
An iron-promoted rhodium-based catalyst is a key step forward for the realization of small-scale on-board reformers to convert biomass into hydrogen fuel for powering vehicles. Credit: Ryan McVay/Photodisc/Thinkstock

A*STAR researchers are helping to advance the development of hydrogen-powered cars by producing innovative materials that could make on-board hydrogen generators a reality. Hydrogen is a renewable resource with the potential to power everything from households to cars, but its use is currently limited by a lack of green and practical production methods.

Current approaches to generating as a power source are anything but environmentally friendly. Obtaining hydrogen through steam reforming and electrolysis of water—the splitting of water into hydrogen and oxygen by applying an electric current—requires high energy input and fossil fuels. In contrast, the process of ethanol steam reforming (ESR) uses ethanol derived from renewable biomass to produce hydrogen and other products.

One drawback of ESR, however, is that it requires high reaction temperatures to proceed and therefore a catalyst is needed to spur on the reaction. Another downside of ESR is that it often produces as a byproduct, which is toxic and can also lead to poisoning of .

Luwei Chen, Armando Borgna and colleagues at the A*STAR Institute of Chemical and Engineering Sciences have developed an iron-promoted rhodium-based catalyst on a calcium-modified aluminum oxide support for ESR. This catalyst enables hydrogen to be generated more efficiently with less environmental damage as the reaction can occur at temperatures as low as 350 degrees Celsius and produce almost no carbon monoxide as a byproduct. The presence of iron oxide enables carbon monoxide to be converted into carbon dioxide and hydrogen via a reaction known as the water–gas shift reaction. Thus, the iron promotion effect on the rhodium-based catalyst is the key to removing carbon monoxide—something that is exceedingly difficult to achieve on rhodium alone.

Additional benefits of ESR are the commercial advantages stemming from the catalyst being quite stable and having a long active lifetime. This means that the catalyst will permit long cycle lengths, minimize the regeneration frequency and reduce the operational downtime for on-board steam reformers. Chen explains that these factors are "essential for maintaining profitable operations in reforming units. Similarly, a stable catalyst would reduce the operating cost for an on-board reformer."

Chen notes that the will enable "better operational flexibility in terms of economics and on-board reformer size (since carbon monoxide purification units can be removed)," which she says will "make a significant impact in the design of efficient and simple on-board reactors." Hence, this research is promising for advancing the realization of small-scale on-board reformers for hydrogen-powered cars.

Explore further: Rhodium-iron catalyst helps increase yield of hydrogen gas in steam reforming of ethanol

More information: Choong, C. K. S., Chen, L., Du, Y., Wang, Z., Hong, L. & Borgna, A. "Rh–Fe/Ca–Al2O3: A unique catalyst for CO-free hydrogen production in low temperature ethanol steam reforming." Topics in Catalysis 57, 627–636 (2014). dx.doi.org/10.1007/s11244-013-0221-0

Related Stories

New method for producing clean hydrogen

May 21, 2013

Duke University engineers have developed a novel method for producing clean hydrogen, which could prove essential to weaning society off of fossil fuels and their environmental implications.

NASA is catalyst for hydrogen technology

October 22, 2014

NASA answered a call to help the world's largest aerospace company develop a better way to generate electricity for its aircraft. Instead, it wound up helping a very small technology company to thrive.

Recommended for you

Tiny 'water bears' can teach us about survival

March 20, 2019

Earth's ultimate survivors can weather extreme heat, cold, radiation and even the vacuum of space. Now the U.S. military hopes these tiny critters called tardigrades can teach us about true toughness.

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Eikka
not rated yet Nov 05, 2014
. Hydrogen is a renewable resource


Resources are something you already have, not something you can have after you make it.

Calling hydrogen a "renewable resource" or a "power source" is just propaganda because it isn't any of that. Other resources are spent and other power sources are used more in making it, making it rather a power drain and a waste of resources instead.
Eikka
not rated yet Nov 05, 2014
One drawback of ESR, however, is that it requires high reaction temperatures to proceed and therefore a catalyst is needed to spur on the reaction. Another downside of ESR is that it often produces carbon monoxide as a byproduct, which is toxic and can also lead to poisoning of hydrogen fuel cells.


The third drawback of ESR is that every gallon of ethanol requires 2/3rds of a gallon of fossil fuels to produce - even when the biomass used in the production is itself renewable, because the cultivation and refining of said biomass runs on fossil fuels.

If we were to use the ethanol to produce more ethanol, we'd be spending nearly 80% of our available energy just to make more fuel, which would mean that we couldn't maintain the complexity of our societies and would collapse right back to the stone age.

PPihkala
not rated yet Dec 22, 2014
The only reasonable way to generate hydrogen is the way Solar Hydrogen Trends is using. And because it has better COP than anything else I know of, it is THE way to make energy. Anything else is just wasting resourses. They convert water to hydrogen using small amount of direct current. Result is massive amounts of hydrogen, enough to self-sustain the process many times over. When that hydrogen is burned, result is more water than one started with, so the water can also be looped for self-sustain.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.