Cheaper hydrogen fuel cell could mean better green energy options

Date:
April 25, 2022
Source:
Imperial College London
Summary:
Researchers have developed a hydrogen fuel cell that uses iron
instead of rare and costly platinum, enabling greater use of
the technology.



FULL STORY ========================================================================== Imperial researchers have developed a hydrogen fuel cell that uses
iron instead of rare and costly platinum, enabling greater use of the technology.


========================================================================== Hydrogen fuel cells convert hydrogen to electricity with water vapour
as the only by-product, making them an attractive green alternative for portable power, particularly for vehicles.

However, their widespread use has been hampered in part by the cost of
one of the primary components. To facilitate the reaction that produces
the electricity, the fuel cells rely on a catalyst made of platinum,
which is expensive and scarce.

Now, a European team led by Imperial College London researchers has
created a catalyst using only iron, carbon, and nitrogen -- materials
that are cheap and readily available -- and shown that it can be used
to operate a fuel cell at high power. Their results are published today
in Nature Catalysis.

Lead researcher Professor Anthony Kucernak, from the Department of
Chemistry at Imperial, said: "Currently, around 60% of the cost of a
single fuel cell is the platinum for the catalyst. To make fuel cells
a real viable alternative to fossil-fuel-powered vehicles, for example,
we need to bring that cost down.

"Our cheaper catalyst design should make this a reality, and allow
deployment of significantly more renewable energy systems that use
hydrogen as fuel, ultimately reducing greenhouse gas emissions and putting
the world on a path to net-zero emissions." The team's innovation was
to produce a catalyst where all the iron was dispersed as single atoms
within an electrically conducting carbon matrix.

Single-atom iron has different chemical properties than bulk iron,
where all the atoms are clustered together, making it more reactive.

These properties mean the iron boosts the reactions needed in the fuel
cell, acting as a good substitute for platinum. In lab tests, the team
showed that a single-atom iron catalyst has performance approaching that
of platinum-based catalysts in a real fuel cell system.

As well as producing a cheaper catalyst for fuel cells, the method the
team developed to create could be adapted for other catalysts for other processes, such as chemical reactions using atmospheric oxygen as a
reactant instead of expensive chemical oxidants, and in the treatment
of wastewater using air to remove harmful contaminants.

First author Dr Asad Mehmood, from the Department of Chemistry at
Imperial, said: "We have developed a new approach to make a range of
'single atom' catalysts that offer an opportunity to allow a range of
new chemical and electrochemical processes. Specifically, we used a
unique synthetic method, called transmetallation, to avoid forming iron clusters during synthesis. This process should be beneficial to other scientists looking to prepare a similar type of catalyst." The team collaborated with UK fuel cell catalyst manufacturer Johnson Matthey to
test the catalyst in appropriate systems and hope to scale up their new catalyst so it can be used in commercial fuel cells. In the meantime,
they are working to improve the stability of the catalyst, so it matches platinum in durability as well as performance.


========================================================================== Story Source: Materials provided by Imperial_College_London. Original
written by Hayley Dunning. Note: Content may be edited for style and
length.


========================================================================== Journal Reference:
1. Mehmood, A., Gong, M., Jaouen, F. et al. High loading of single
atomic
iron sites in Fe-NC oxygen reduction catalysts for proton exchange
membrane fuel cells. Nat Catal, 2022 DOI: 10.1038/s41929-022-00772-9 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220425121110.htm

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