Nav: Home

Artificial photosynthesis gets big boost from new catalyst

November 20, 2017

A new catalyst created by U of T Engineering researchers brings them one step closer to artificial photosynthesis -- a system that, just like plants, would use renewable energy to convert carbon dioxide (CO2) into stored chemical energy. By both capturing carbon emissions and storing energy from solar or wind power, the invention provides a one-two punch in the fight against climate change.

"Carbon capture and renewable energy are two promising technologies, but there are problems," says Phil De Luna, one of the lead authors of a paper published today in Nature Chemistry. "Carbon capture technology is expensive, and solar and wind power are intermittent. You can use batteries to store energy, but a battery isn't going to power an airplane across the Atlantic or heat a home all winter: for that you need fuels."

De Luna and his co-lead authors Xueli Zheng and Bo Zhang -- who conducted their work under the supervision of Professor Ted Sargent -- aim to address both challenges at once, and they are looking to nature for inspiration. They are designing an artificial system that mimics how plants and other photosynthetic organisms use sunlight to convert CO2 and water into molecules that humans can later use for fuel.

As in plants, their system consists of two linked chemical reactions: one that splits H2O into protons and oxygen gas, and another that converts CO2 into carbon monoxide, or CO. (The CO can then be converted into hydrocarbon fuels through an established industrial process called Fischer-Tropsch synthesis.)

"Over the last couple of years, our team has developed very high-performing catalysts for both the first and the second reactions," says Zhang, who contributed to the work while a post-doctoral fellow at U of T and is now a professor at Fudan University. "But while the second catalyst works under neutral conditions, the first catalyst requires high pH levels in order to be most active."

That means that when the two are combined, the overall process is not as efficient as it could be, as energy is lost when moving charged particles between the two parts of the system.

The team has now overcome this problem by developing a new catalyst for the first reaction -- the one that splits water into protons and oxygen gas. Unlike the previous catalyst, this one works at neutral pH, and under those conditions it performs better than any other catalyst previously reported.

"It has a low overpotential, which means less electrical energy is needed to drive the reaction forward," says Zheng, who is now a postdoctoral scholar at Stanford University. "On top of that, having a catalyst that can work at the same neutral pH as the CO2 conversion reaction reduces the overall potential of the cell."

In the paper, the team reports the overall electrical-to-chemical power conversion efficiency of the system at 64 per cent. According to De Luna, this is the highest value ever achieved for such a system, including their previous one, which only reached 54 per cent.

The new catalyst is made of nickel, iron, cobalt and phosphorus, all elements that are low-cost and pose few safety hazards. It can be synthesized at room temperature using relatively inexpensive equipment, and the team showed that it remained stable as long as they tested it, a total of 100 hours.

Armed with their improved catalyst, the Sargent lab is now working to build their artificial photosynthesis system at pilot scale. The goal is to capture CO2 from flue gas -- for example, from a natural gas-burning power plant -- and use the catalytic system to efficiently convert it into liquid fuels.

"We have to determine the right operating conditions: flow rate, concentration of electrolyte, electrical potential," says De Luna. "From this point on, it's all engineering."

The team and their invention are semi-finalists in the NRG COSIA Carbon XPRIZE, a $20 million challenge to "develop breakthrough technologies that will convert CO? emissions from power plants and industrial facilities into valuable products."

The project was the result of an international and multidisciplinary collaboration. The Canadian Light Source in Saskatchewan provided the high-energy x-rays used to probe the electronic properties of the catalyst. The Molecular Foundry at the U.S. Department of Energy's Lawrence Berkeley National Laboratory did theoretical modelling work. Financial and in-kind support were provided by the Natural Sciences and Engineering Research Council, the Canada Foundation for Innovation, Tianjin University, Fudan University and the Beijing Light Source.

As for what has kept him motivated throughout the project, De Luna points to the opportunity to make an impact on some of society's biggest environmental challenges.

"Seeing the rapid advancement within the field has been extremely exciting," he says. "At every weekly or monthly conference that we have within our lab, people are smashing records left and right. There is still a lot of room to grow, but I genuinely enjoy the research, and carbon emissions are such a big deal that any improvement feels like a real accomplishment."

University of Toronto Faculty of Applied Science & Engineering

Related Climate Change Articles:

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.
Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.
Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.
Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.
Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.
A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.
Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).
Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.
Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.
Could climate change cause infertility?
A number of plant and animal species could find it increasingly difficult to reproduce if climate change worsens and global temperatures become more extreme -- a stark warning highlighted by new scientific research.
More Climate Change News and Climate Change Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at     You can read The Transition Integrity Project's report here.