Did you
know?
Cutting-edge chemistry
Giving fuel cells a vitamin boost
jose gil/shutterstock
Vitamin B12 is essential
for a healthy brain and
nervous system. It is
found in fish, meat and
dairy products.
Scientists have found a
cheaper alternative to
platinum catalysts in fuel
cells – combining carbon
and vitamin B12
With the increasing energy demands of the 21st century
creating a pressing interest in alternative power sources,
the demand for high performing, state-of-the-art fuel
cells has never been greater. However, these fuel cells
require the precious metal platinum to generate their
high power output. This drawback has led scientists
in Taiwan to develop a competitive replacement by
combining carbon, and curiously, vitamin B12.
Find out more
ation
For more inform
istr y of fuel
em
about the ch
cells visit
uel_cell and
http://bit.ly/f
uel_cell2
http://bit.ly/f
8 | The Mole | March 2012
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‘The limited abundance of platinum and other noble
metals on Earth restricts the development of fuel cells.
Searching for a non-noble-metal catalyst is a major
issue,’ explains Kuei-Hsien Chen, from the Institute of
Atomic and Molecular Science, Taipei, who, along with
other colleagues, has developed this peculiar solution.
produce a cathode that can achieve this. So they have
had to resort to loading high amounts of expensive
platinum onto the cathode to generate the required ORR
rate.
Chen and his co-workers have been able to do away with
the need for platinum altogether, by using cheap carbon
that has vitamin B12 dispersed throughout to form the
cathode of their polymer electrolyte fuel cell (PEFC). The
performance of this cathode doesn’t quite match that of
platinum based cathodes, but at a fraction of the cost,
this cathode could open up real opportunities for the
practical application of these fuel cells.
Fuel cell expert John Varcoe, from the University of
Surrey, UK, thinks that Chen’s advance clearly shows
‘promise for use as a fuel cell catalyst’. However,
he urges caution by saying that the fuel cell’s
performance over ‘many thousands of hours will need
to be demonstrated before it will rival current (more
expensive) fuel cell catalysts’.
To generate electricity, most modern fuel cell devices
require an oxygen reduction reaction (ORR) at the
cathode of the cell, whilst another chemical (often
hydrogen) is simultaneously oxidised at the anode. This
redox reaction for power generation has been limited by
the slow ORR process, which needs complex enzymes to
Chen hopes to continue to develop his PEFC to make the
proceed at any meaningful rate.
cathode more effective. In the meantime, this research
Although scientists have been investigating methods
may make fuel cells more accessible as a power source
for speeding up the ORR, it has been really difficult to
for the world’s future energy needs. Ross McLaren
www.rsc.org/TheMole
2/10/2012 8:20:51 AM
Nanoear listens in on cellular motoring
Fourier
transforms
A Fourier transform is a
mathematical operation
that allows scientists
to separate out the
component parts of a
waveform.
Find out more at
To test this, the team used a camera to record the
movement of an optically-trapped gold nanoparticle
in the presence of a sound source. Using a Fourier
transform, they were able to disentangle the motion
caused by the sound waves from that of normal
Brownian motion. The result, says Feldmann, is ‘a
highly sensitive acoustic detector that provides
a very local source of information about the
microworld’.
http://bit.ly/ftransform
Feldmann says that the nanoear could be useful
in studying cellular processes. Gail McConnell,
a research fellow in biophotonics at the
University of Strathclyde, UK, agrees. ‘It would
be marvellous if mutants of the motor proteins
that impair function could be listened to, to
see if there was a change in the humming of
the motor,’ she says. McConnell notes, however,
this is only possible if the vibrations are powerful
enough to be noticeable above the background
Brownian noise.
On observing the movements of such a trapped particle,
Feldmann proposed that the particle’s response to an
acoustic wave should reliably correspond to features
of the wave. ‘Imagine an apple hanging on a branch
of an apple tree and being shaken by wind,’ explains
Feldmann. ‘By observing the apple’s motion one could
derive properties of the wind.’
phys. rev. lett
Another limitation is the size of the nanoparticle,
says Ricardo Arias-González, who leads the optical
Just as the macroscopic world is filled with the rattle
manipulation lab at the Madrid Institute of Advanced
and hum of machinery, the actions of molecular and
Studies in Nanoscience in Spain. Arias-González
cellular ‘machinery’ also produce tiny vibrations that
suspects that molecular motors may be out of earshot
resonate throughout the microscopic world. The sound
but that the nanoear could listen to processes that
a car engine makes can indicate if there’s a fault and
involve many proteins working together. ‘It is highly
by extension, the sounds made by the ‘machines’ that
innovative,’ he says. ‘I would find it quite exciting
control cells could also provide useful information about
characterising the noises in the vicinity of an individual
the processes they control. Listening to these sounds,
cell. This might provide information on collective tasks
however, is currently beyond even the keenest ears.
that may not be easy to inspect with microscopy.’
Inspired by this, Jochen Feldmann and colleagues at the
Phillip Broadwith
Ludwig Maximilian University of Munich have developed
a ‘nanoear’, that is capable of detecting these tiny
vibrations. Feldmann’s nanoear is an adaptation of
optical tweezers: a technique that uses laser beams to
trap an object within a fixed volume of space, commonly
used to manipulate objects and perform measurements
at the microscale and nanoscale.
Find out more
Lear n more ab
out the
‘nanoear ’ at
http://dx.doi.o
rg/10.1103
/Physics.5.1
An optically trapped
nanoparticle can act
as an ultrasensitive
detector of sound
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March 2012 | The Mole | 9
2/10/2012 8:26:18 AM