After a group of scientists led by UNSW showed how to produce the hydrogen
needed to power hydrogen-powered automobiles far more cheaply and
sustainably, the technology may soon be more than just a curiosity.
Scientists from UNSW Sydney, Griffith University, and Swinburne University
of Technology demonstrated in a recent study published in Nature
Communications that low-cost metals like iron and nickel can be used as
catalysts to speed up this chemical reaction and use less energy to capture
hydrogen by splitting it from oxygen in water.
The abundant metals iron and nickel would take the place of the precious
metals ruthenium, platinum, and iridium, which are now thought to be
standard catalysts in the "water-splitting" process.
The process of water splitting, according to Professor Chuan Zhao of the
UNSW School of Chemistry, involves applying an electric charge to water
through two electrodes, allowing hydrogen to be separated from oxygen and
utilized as fuel for a fuel cell.
"We apply our catalyst to the electrodes in order to lower energy
consumption," he explains. The atomic meeting point of iron and nickel on
this catalyst is a small nanoscale interface that serves as an active site
for water splitting. Here, oxygen may be discharged as a waste that is
benign to the environment and hydrogen can be separated from it and
recovered for use as fuel."
A record-high efficiency nickel-iron electrode for oxygen production was
created in 2015 by Prof. Zhao's group. Prof. Zhao notes that iron and nickel
by themselves are not effective catalysts for the production of hydrogen,
but that their combination at the nanoscale is "where the magic
happens."
"These materials' properties are fundamentally changed by the nanoscale
interface," he claims. According to our findings, the nickel-iron catalyst
for hydrogen production can be just as active as the platinum one.
In addition, by employing components that are readily available on Earth,
we might reduce not just the cost of production by employing one catalyst
rather than two, but also the cost of creating both hydrogen and oxygen
through the use of our nickel-iron electrode.
A cursory look at the current metal prices demonstrates why this could be
the catalyst required to accelerate the shift to the so-called hydrogen
economy. Priced per kilogram, iron is $0.13 while nickel is $19.65. In
comparison, the prices of ruthenium, platinum, and iridium are $11.77,
$42.13, and $69.58 per gram, respectively—a significant price difference of
thousands of times.
Prof. Zhao states, "We currently have this huge incentive to move from our
fossil fuel economy to a hydrogen economy so that we can be using hydrogen
as a clean energy carrier which is abundant on Earth."
"The hydrogen economy has been discussed for a long time, but it appears to
be here to stay this time."
According to Prof. Zhao, if the technology for water-splitting is further
improved, hydrogen fuelling stations like to gas stations may exist in the
future, where you could fill up your hydrogen fuel-cell vehicle with
hydrogen gas created by this water-splitting reaction. If an electric
automobile powered by lithium batteries were to be refueled, it might be
completed in a matter of minutes as opposed to hours.
"We hope that stations like these will be able to use our research to
produce their own hydrogen with inexpensive, effective catalysts and
sustainable sources like solar and water."
