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July 29, 2023
By
Brian
Westenhaus
Green Hydrogen Gets Greener With Record-Breaking Solar
Device
- The solar device, known as a
photoelectrochemical cell, integrates halide perovskite
semiconductors with electrocatalysts in a single, scalable device
that can split water into hydrogen and oxygen using solar energy.
-
A key innovation of the device is the use of an anti-corrosion
barrier that protects the cheap halide perovskite semiconductor from
water, without hindering the transfer of electrons, overcoming
previous challenges with water instability.
-
The breakthrough technology could have broad applications in driving
chemical reactions that convert feedstocks into fuels using
solar-harvested electricity.
![](images/images_07_31_2023/2023-07-28_hutcmxsine.jpg)
Rice University engineers have created a device
that “turns sunlight into hydrogen” with record-breaking efficiency.
The device integrates next-generation halide perovskite semiconductors
with electrocatalysts in a single, durable, cost-effective and
scalable device. The press release believes the engineers have set a
new standard for hydrogen technology. The device is factually a solar
driven water splitting cell.
According to a study published in Nature Communications, the device
achieved a 20.8% solar-to-hydrogen conversion efficiency. Today the
study is not behind a paywall.
The new technology is a significant step forward for clean energy and
could serve as a platform for a wide range of chemical reactions that
use solar-harvested electricity to convert feedstocks into fuels.
The lab of chemical and biomolecular engineer Aditya Mohite built the
integrated photoreactor using an anticorrosion barrier that insulates
the semiconductor from water without impeding the transfer of
electrons.
Austin Fehr, a chemical and biomolecular engineering doctoral student
and one of the study’s lead authors commented, “Using sunlight as an
energy source to manufacture chemicals is one of the largest hurdles
to a clean energy economy. Our goal is to build economically feasible
platforms that can generate solar-derived fuels. Here, we designed a
system that absorbs light and completes electrochemical
water-splitting chemistry on its surface.”
The device is known as a photoelectrochemical cell because the
absorption of light, its conversion into electricity and the use of
the electricity to power a chemical reaction all occur in the same
device. Until now, using photoelectrochemical technology to produce
green hydrogen was hampered by low efficiencies and the high cost of
semiconductors.
“All devices of this type produce green hydrogen using only sunlight
and water, but ours is exceptional because it has record-breaking
efficiency and it uses a semiconductor that is very cheap,” Fehr
added.
The Mohite lab and its collaborators created the device by turning
their highly-competitive solar cell into a reactor that could use
harvested energy to split water into oxygen and hydrogen. The
challenge they had to overcome was that halide perovskites are
extremely unstable in water and coatings used to insulate the
semiconductors ended up either disrupting their function or damaging
them.
Michael Wong, a Rice chemical engineer and co-author on the study
noted, “Over the last two years, we’ve gone back and forth trying
different materials and techniques.” After lengthy trials failed to
yield the desired result, the researchers finally came across a
winning solution.
“Our key insight was that you needed two layers to the barrier, one to
block the water and one to make good electrical contact between the
perovskite layers and the protective layer,” Fehr said. “Our results
are the highest efficiency for photoelectrochemical cells without
solar concentration, and the best overall for those using halide
perovskite semiconductors.
“It is a first for a field that has historically been dominated by
prohibitively expensive semiconductors, and may represent a pathway to
commercial feasibility for this type of device for the first time
ever,” Fehr said.
The researchers showed their barrier design worked for different
reactions and with different semiconductors, making it applicable
across many systems.
Mohite said, “We hope that such systems will
serve as a platform for driving a wide range of electrons to
fuel-forming reactions using abundant feedstocks with only sunlight as
the energy input.”
“With further improvements to stability and scale, this technology
could open up the hydrogen economy and change the way humans make
things from fossil fuel to solar fuel,” Fehr added.
There is a great deal of optimism in this work. Yet we need to
remember that a top of the line solar collector at best of day is only
going to see about 100 watts of power incoming per square meter. One
has to ask just how useful is free hydrogen going to be in a niche
market.
The technology is very much at its beginning. How far it can go is yet
to be researched and engineered out somewhat more. But even at 20.8%
solar driven water splitting efficiency there is a very long way to
go.
Rice graduate students Ayush Agrawal and Faiz Mandani are lead authors
on the study alongside Fehr. The work was also authored in part by the
National Renewable Energy Laboratory, which is operated by Alliance
for Sustainable Energy LLC for the Department of Energy under Contract
DE-AC36-08GO28308.
By Brian Westenhaus via New Energy and Fuel
Green Play Ammonia™, Yielder® NFuel Energy.
Spokane, Washington. 99212
www.exactrix.com
509 995 1879 cell, Pacific.
Nathan1@greenplayammonia.com
exactrix@exactrix.com
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