Fuel cell breakthrough to low-cost nickel-based catalyst

University of Delaware Distinguished Engineering Professor Yushan Yan, at the wheel of a fuel cell vehicle, is conducting research on the use of nickel as a catalyst in an alkaline electrolyte that promises to bring down the cost of …more


"Planes, Trains and Automobiles" is a popular comedy from the 1980s, but there's nothing funny about the amount of energy consumed by our nation's transportation sector.

This sector—which includes passenger cars, trucks, buses, and rail, marine, and air transport—accounts for more than 20 percent of America's energy use, mostly in the form of fossil fuels, so the search is on for environmentally friendly alternatives.

The two most promising current candidates for cars are fuel cells, which convert the chemical energy of hydrogen to electricity, and rechargeable batteries.

The University of Delaware's Yushan Yan believes that fuel cells will eventually win out.

"Both fuel cells and batteries are clean technologies that have their own sets of challenges for commercialization," says Yan, Distinguished Engineering Professor in the Department of Chemical and Biomolecular Engineering.

"The key difference, however, is that the problems facing battery cars, such as short driving range and long battery charging time, are left with the customers. By contrast, fuel cell cars demand almost no change in customer experience because they can be charged in less than 5 minutes and be driven for more than 300 miles in one charge. And these challenges, such as hydrogen production and transportation, lie with the engineers."

Yan is prepared to address the biggest challenge fuel cells do face—cost.

He and colleagues recently reported a breakthrough that promises to bring down the cost of hydrogen fuel cells by replacing expensive platinum catalysts with cheaper ones made from metals like nickel. The work is documented in a paper published Jan. 14 in Nature Communications.

The researchers achieved the breakthrough by switching the operating environment from acidic to basic, and they found that nickel matched the activity of platinum.

"This new hydroxide exchange membrane fuel cell can offer high performance at an unprecedented low cost," Yan says.

"Our real hope is that we can put hydroxide exchange membrane fuel cells into cars and make them truly affordable—maybe $23,000 for a Toyota Mirai. Once the cars themselves are more affordable, that will drive development of the infrastructure to support the hydrogen economy."

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Pico-gold clusters break catalysis record!!!

Clusters of just three gold atoms have exceptional
 catalytic activity ©

Chemists in Spain have shown that small clusters of gold atoms are excellent inorganic catalysts with record-breaking efficiency. The clusters, which have been used in the hydration of alkynes, exhibit catalytic turnover frequencies of up to 100,000 per hour at room temperature.

Interest in gold as a catalyst began 25 years ago when chemists realized that nano-sized gold particles could catalyse the oxidation of carbon monoxide better than anything previously known. Since then, gold has been found to catalyse a host of other important reactions, such as the formation of azo compounds, which are used as leather and textile dyes, or intermediates for the production of polyurethane.

But for the most part, industry hasn’t yet turned to gold as a catalyst. The problem is that a lot of the precious metal is required – loadings of about 5% by mole for just a few hundred milligrams of substrate. For this reason, interest in gold as a catalyst has remained primarily academic.




The researchers focused on the ester-assisted hydration of alkynes. In this reaction water turns alkynes into ketones; it used to be used by industry to form acetaldehyde for the production of acetic acid and other chemicals from acetylene using a mercury catalyst.


The Valencia chemists formed the gold clusters by adding the reactant substrate to a solution of gold chloride (AuCl) or chloroauric acid (HAuCl₄). Using ultraviolet spectroscopy and matrix-assisted laser–desorption–ionisation-time-of-flight (MALDI) mass spectroscopy, they found that the reaction began when clusters of between three and five gold atoms formed. Then the reaction proceeded swiftly, with a turnover frequency of 100,000 – that is, converting 100,000 substrate molecules per gold cluster per hour. Such catalytic activity is nearly five orders of magnitude higher than that previously reported, the researchers claim.

‘The higher the dilution, the better the formation of the clusters, [so] extremely low amounts of gold are sufficient to catalyse the reactions,’ says Corma. ‘Clusters are rearranging [with] time in the reaction mixture – but each reaction needs a type of cluster, i.e. a number of atoms of gold clustered, so control of the formation of [a] particular cluster would lead to an even more efficient process.’

The high catalytic turnover ‘is of significance for industrial applications’, says Stephen Hashmi, an organic chemist at Heidelberg University in Germany. ‘The fact that this is possible at room temperature is nice but, as most chemical engineers will confirm, for industrial reactors … room temperature reactivity is not crucial, [and] slightly higher temperatures are preferred.’

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Protein coat prepares catalyst for cascades

By protecting a transition metal catalyst with a protein coat, scientists have managed to couple up biocatalysts and chemical catalysts to perform a cascade reaction.

When students and post-docs moved from Nick Turner’s lab at the University of Manchester, UK, to Tom Ward’s at the University of Basel, Switzerland, it prompted an intriguing collaboration between a group with experience with naturally occurring enzymes and Ward’s group, which creates artificial metalloenzymes by combining transition metal catalysts with proteins. The result was a way of combining traditional enzyme biocatalysts with chemical catalysts to perform reaction cascades.

In our cells, enzymes happily react with a substrate and then pass the product on to another enzyme to perform the next bit of chemistry. Unfortunately for chemists, just introducing a transition metal catalyst into one of these cascades doesn’t work, the catalyst and the enzyme tend to inactivate each other. Instead, to introduce new chemistry, naturally occurring enzymes have to be modified. Or at least that used to be the only option.

Ward’s group has been working on making artificial metalloenzymes by sitting traditional transition metal catalysts inside proteins, creating catalysts that can perform chemistry traditionally unavailable to enzymes. He says it was the transfer of staff from Turner’s lab that led to the next step of combining the artificial metalloenzymes with naturally occurring enzymes.

To test the hypothesis, the group decided to try and use an enzyme Turner was familiar with, monoamine oxidase (MAO), to synthesis enantiopure amines. MAO is a highly selective oxidase which, in collaboration with a reducing agent or catalyst, converts racemic amines just one enantiomer. Usually the catalyst used is heterogeneous, it’s solid and used after the MAO. An artificial metalloenzyme would be homogeneous and allow the reaction to proceed without any intervention between the two steps.

A streptavidin coat protects the metal catalyst and enzyme from each other, so both can function in tandem © NPG

The team created their artificial transfer hydrogenase (ATH) by shielding an iridium containing reduction catalyst with a streptavidin protein. Using just the MAO and the iridium catalyst resulted in nothing, but when the ATH was used instead, the team saw the starts of a cascade. Modifying and improving the enzymes eventually led to conversion efficiencies for some reactions of 99%, with similar enantiomeric excesses.

Corinna Hess from Durham University, UK, says that this work ‘nicely illustrates that artificial enzymes aren’t merely a biochemical novelty, and demonstrates their great promise for catalysis.’ Before adding that ‘the results are highly encouraging for the use of artificial enzymes in industrial biotransformations, and many inorganic motifs still remain to be explored.’

However, for Ward and Turner, improving industrial chemistry is not the ultimate goal. ‘There are better ways of doing that chemistry,’ explains Ward. Instead, the team see their work as a starting point towards introducing inorganic chemistry into cells. 
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