An energy-efficient, cost-effective way to convert the
greenhouse gas into a wide range of chemical feedstocks
SINGAPORE, May 14, 2024
/PRNewswire/ -- Addressing the urgent challenge posed by escalating
carbon dioxide (CO2) emissions and their impact on
climate change, researchers from the National
University of Singapore (NUS) have developed a novel
technique that significantly advances the conversion of waste
carbon dioxide (CO2) into value-added chemicals and
fuels.
Led by Assistant Professor LUM Yanwei from the Department of
Chemical and Biomolecular Engineering under the NUS College of
Design and Engineering, the research team's innovation enables the
direct conversion of CO2 from treated flue gas, a common
by-product of industrial processes, into high-value multi-carbon
(C2+) products such as ethylene and ethanol, essential
raw materials for the production of various everyday compounds such
as plastics, polymers and detergents.
This advancement not only circumvents the need for high-purity
CO2 but also efficiently repurposes a prevalent waste
product, marking a stride towards closing the carbon cycle and
reducing reliance on fossil fuels.
Marrying catalyst design with electrolyte selection
Carbon capture, utilisation and storage is a fundamental process
to a sustainable future, relying on a suite of technologies among
which the electrochemical reduction of CO2 is vital. The
process, which transforms CO2 into a range of valuable
feedstocks for chemicals and fuels, traditionally demands
high-purity CO2, leading to significant costs due to the
energy-intensive purification of the compound from sources like
flue gases. Furthermore, the presence of oxygen impurities in flue
gas results in undesired side reactions, which significantly
reduces the efficiency of the CO2 reduction process.
Asst Prof Lum's team aimed to sidestep these challenges by
integrating catalyst design with electrolyte selection. In their
recent study which was published in the prestigious scientific
journal Nature Communications on 26 February
2024, the researchers first introduced a new method to
design catalysts with greatly enhanced efficiencies for the
electrochemical conversion of CO2. Utilising this
approach, they designed a nickel catalyst boasting exceptional
performance for CO2 reduction, achieving an impressive
efficiency rate exceeding 99 percent.
In another study that builds on the aforementioned one, the NUS
team designed a composite system by sequentially layering this
nickel catalyst onto a copper surface. "We found that integrating
acidic electrolytes with this composite system significantly
suppresses the undesired side reactions from oxygen impurities in
flue gas," explained Asst Prof Lum. Impressively, this system
demonstrated comparable performance with systems that utilise pure
CO2 as feedstock. The second study was published in the
same journal on 9 February 2024.
Asst Prof Lum highlighted the potential economic impact of their
research, "The cost of purifying CO2 can amount to about
USD 70 to 100 per ton, which can
constitute about 30 per cent of the costs involved in converting
CO2 to feedstocks such as ethylene through
electrochemical means."
"Our novel technique demonstrates a potential pathway for the
development of efficient electrolysers for the direct conversion of
CO2 in flue gas, using simple yet effective electrolyte
and catalyst design strategies to advance integrated sustainability
solutions," added Asst Prof Lum.
Scaling up for large-scale applications
The potential implications of this research extend beyond the
production of ethylene and ethanol. By adjusting the catalyst
system, the researchers' technique could be applied to synthesise
other valuable chemicals, such as acetate and propanol which are
used in the production of everyday products such as adhesives and
disinfectants respectively. This versatility offers a broad
platform for converting waste CO2 into a diverse range
of chemicals, underscoring the technique's adaptability to
different industrial needs.
"We are seeing strong interest from the industry and are
currently in talks with some companies to further advance this
research," said Asst Prof Lum. "Our goal is to enhance the energy
efficiency and scalability of our system, moving beyond
laboratory-scale experiments towards developing prototype reactors
that can be applied in industrial settings."
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SOURCE National University of
Singapore