David Sinton

New contaminant-tolerant catalyst could help capture carbon directly from smokestacks

rahul.kalvapalle — Wed, 24 Jul 2024 16:45:48 +0000

New contaminant-tolerant catalyst could help capture carbon directly from smokestacks

rahul.kalvapalle Wed, 07/24/2024 - 12:45

Cutline

PhD students Rui Kai (Ray) Miao (left) and Panos Papangelakis (right) hold up a new catalyst that is designed to convert captured CO2 gas into valuable products (photo by Tyler Irving)

Tyler Irving

Topic

Breaking Research

David Sinton

Faculty of Applied Science & Engineering

Mechanical & Industrial Engineering

Research & Innovation

Sustainability

Subheadline

The research marks an important step towards developing economically viable techniques for carbon capture and storage

Researchers at the �ؿ�ζSM’s Faculty of Applied Science & Engineering have designed a catalyst that can efficiently convert captured carbon into valuable products – even in the presence of contaminants that degrade the performance of current versions.

The discovery, described in a paper published in Nature Energy, is an important step toward more economically viable techniques for carbon capture and storage that could be added to existing industrial processes.

“Today, we have more and better options for low-carbon electricity generation than ever before,” says David Sinton, professor in the department of mechanical and industrial engineering and senior author on the paper. “But there are other sectors of the economy that will be harder to decarbonize: for example, steel and cement manufacturing. To help those industries, we need to invent cost-effective ways to capture and upgrade the carbon in their waste streams.”

Sinton and his team use devices known as electrolyzers to convert CO2 and electricity into products such as ethylene and ethanol. These carbon-based molecules can be sold as fuels or used as chemical feedstocks for making everyday items such as plastic.

Inside the electrolyzer, the conversion reaction happens when three elements — CO2 gas, electrons and a water-based liquid electrolyte — come together on the surface of a solid catalyst.

The catalyst is often made of copper but may also contain other metals or organic compounds that can further improve the system. Its function is to speed up the reaction and minimize the creation of undesirable byproducts like hydrogen gas, which reduce the efficiency of the overall process.

While several high-performing catalysts have been developed around the world, nearly all of them are designed to operate with a pure CO2 feed. But if the carbon in question comes from smokestacks, the feed is likely to be anything but pure.

“Catalyst designers generally don’t like dealing with impurities, and for good reason,” says Panos Papangelakis, a PhD student in mechanical engineering and a co-lead author on the paper.

“Sulphur oxides such as SO2 poison the catalyst by binding to the surface. This leaves fewer sites for CO2 to react, and it also causes the formation of chemicals you don’t want.

“It happens really fast: whereas some catalysts can last hundreds of hours on a pure feed, if you introduce these impurities, within minutes they can be down to five per cent efficiency.”

Although there are well-established methods to remove impurities from CO2-rich exhaust gases before feeding them into the electrolyzer, these require substantial time, energy and expense. Furthermore, in the case of SO2, even a little bit can be a big problem.

“Even if you bring your exhaust gas down to less than 10 parts per million, or 0.001 per cent of the feed, the catalyst can still be poisoned in under two hours,” says Papangelakis.

In the paper, the team describes how two key changes to a typical copper-based catalyst can make it more resilient to SO2.

On one side, they added a thin layer of polyteterafluoroethylene, also known as Teflon. This non-stick material changes the chemistry at the catalyst surface, impeding the reactions that enable SO2 poisoning to take place.

On the other side, they added a layer of Nafion, an electrically conductive polymer often used in fuel cells. This complex, porous material contains some areas that are hydrophilic, meaning they attract water, as well as other areas that are hydrophobic, meaning they repel water. This structure makes it difficult for SO2 to reach the catalyst surface.

The team then fed this catalyst with a mix of CO2 and SO2, with the latter at a concentration of about 400 parts per million, typical of an industrial waste stream. Even under these tough conditions, the new catalyst performed well.

“In the paper, we report a Faraday efficiency — a measure of how many of the electrons ended up in the desired products — of 50 per cent, which we were able to maintain for 150 hours,” says Papangelakis.

“There are some catalysts out there that might start at a higher efficiency, maybe 75 per cent or 80 per cent. But again, if you expose them to SO2, within minutes or at most a couple of hours, that drops down to almost nothing. We were able to resist that.”

Papangelakis says that because his team’s approach doesn’t affect the composition of the catalyst itself, it should be widely applicable. In other words, teams that have already perfected high-performing catalysts should be able to use similar coatings to confer resistance to sulphur oxide poisoning.

Although sulphur oxides are the most challenging impurity in typical waste streams, they are not the only ones, and it’s the full set of chemical contaminants that the team is turning to next.

“There are lots of other impurities to consider, such as nitrogen oxides, oxygen, etc.,” says Papangelakis.

“But the fact that this approach works so well for sulphur oxides is very promising. Before this work, it was just taken for granted that you’d have to remove the impurities before upgrading CO2.

“What we’ve shown is that there might be a different way to deal with them, which opens up a lot of new possibilities.”

Season 2 of Groundbreakers series: ‘Diverse research communities solving the world’s grand challenges’

rahul.kalvapalle — Tue, 27 Sep 2022 16:18:56 +0000

Season 2 of Groundbreakers series: ‘Diverse research communities solving the world’s grand challenges’ rahul.kalvapalle Tue, 09/27/2022 - 12:18

Topic

Our Community

Climate Positive Energy

Groundbreakers

Institutional Strategic Initiatives

Climate Change

David Sinton

Faculty of Applied Science & Engineering

Faculty of Arts & Science

Political Science

Research & Innovation

School of the Environment

Sustainability

Self-driving vehicles. Renewable energy storage. Advanced materials and molecules. Experts at the �ؿ�ζSM are leading the way in all three areas – and more – as they work to address one of the biggest and most complex challenges facing the planet: a changing climate.

Their creative and cutting-edge work is part of the Climate Positive Energy strategic initiative. It’s one of several cross-disciplinary collaborations at U of T that aim is to tackle the most pressing problems of our time – and is highlighted in the Season 2 premiere of the Groundbreakers video series, released Sept. 27.

“What excites me about the strategic initiatives are the people behind these large research networks that are bringing together diverse communities to solve the world’s grand challenges,” Timothy Chan, U of T’s associate vice-president and vice-provost strategic initiatives, says in the video.

The premiere episode offers a behind-the-scenes glimpse at how researchers are tackling climate change and renewable energy challenges from scientific, social, economic and policy perspectives. They include: David Sinton, director of the Climate Positive Energy strategic initiative and a professor in the department of mechanical and industrial engineering; Celine Xiao, a PhD candidate in the Sinton Lab and co-founder of the E-Quester carbon capture team; and Kate Neville, associate professor in the department of political science and School of the Environment in the Faculty of Arts & Science.

Groundbreakers is a multimedia series that also includes articles on U of T News. Stay tuned for more content.

Watch the Season 2 premiere

Five U of T faculty named to Royal Society college

sgupta — Fri, 18 Sep 2015 15:39:24 +0000

Five U of T faculty named to Royal Society college sgupta Fri, 09/18/2015 - 11:39

Cutline

Professor Aaron Wheeler is one of five U of T faculty named to the RSC College of New Scholars [photo by Diana Tyszko, Faculty of Arts & Science]

Arthur Kaptainis

Author legacy

Arthur Kaptainis

Our Faculty & Staff

Subodh Verma

Royal Society of Canada

Subheadline

College of New Scholars honours early achievers

Five �ؿ�ζSM researchers are among the 2015 inductees to the College of New Scholars, Artists and Scientists of the Royal Society of Canada.

Established last year, this fourth and most recent division of the 133-year-old RSC is intended to recognize high achievement, and especially interdisciplinary work, by Canadians and permanent residents at an early stage of their career.

“The surest measure of a great university is the emergence of brilliant young artists, researchers and scholars to build on the work of distinguished senior faculty,” said Vivek Goel, vice president, research and innovation of the �ؿ�ζSM. “I am immensely proud that U of T is amply represented in this college of the Royal Society.”

Two of the members hail from the Faculty of Arts & Science. Aneil Flett Agrawal is a distinguished professor in the department of ecology and evolutionary biology who won the faculty’s Outstanding Teaching Award in 2011 and was named a Steacie Fellow in 2013. Aaron Wheeler, another Steacie Fellow, is acclaimed for his work in “lab-in-a-chip” technology and the integration of microchannels and microfluids. He is a professor in the department of chemistry.

Dr. Subodh Verma from the department of surgery of the Faculty of Medicine works on the connection between breast cancer genes and the degree of cardiac damage caused by chemotherapeutic drugs. A practising surgeon at St. Michael’s Hospital, he is a recipient of the Royal College of Physicians and Surgeons of Canada Gold Medal in Surgery.

Daniyal Zuberi is cross-appointed to the School of Public Policy & Governance and the Factor-Inwentash Faculty of Social Work. His innovative social policy research has made important contributions to the study of urban poverty, inequality, health, education, employment and social welfare.

David Sinton from the department of mechanical and industrial engineering of the Faculty of Applied Science & Engineering was the director from 2012 to 2015 of the Institute for Sustainable Energy. His research involves the study and application of small-scale fluid mechanics for use in energy systems and analysis.

Criteria for admission to the College of New Scholars, Artists and Scientists include new research approaches, interdisciplinary flexibility and an emphasis on diverse membership with representation by women, First Nations, immigrants and visible minorities. Candidates are to be admitted not later than 15 years after earning their doctorates. Membership is offered for seven years.

For a complete list of incoming College members go to http://www.rsc-src.ca.

picpath

sites/default/files/wheeler.pic_.jpg