Cao Thang Dinh’s research centers on transforming carbon dioxide (CO2), a greenhouse gas, into valuable resources, including energy storage. His work focuses on electrochemical CO2 conversion, a process that utilizes renewable electricity to turn CO2 and water into renewable fuels and chemicals. This innovative approach offers a trifecta of benefits: reducing CO2 emissions by converting them into chemical feedstock, enabling large-scale storage of intermittent renewable energy, and sustainably producing materials like plastics from CO2 and water. Cao Thang Dinh’s pioneering work also addresses the challenge of enhancing performance metrics like reaction rate, energy efficiency, and product selectivity. His efforts promise a greener future by unlocking the potential of CO2 capture and conversion technologies.
Which wall does your research break?
My research focuses on developing technologies for capturing and converting carbon dioxide (CO2), a greenhouse gas, into valuable products. A process that we are working on, namely electrochemical CO2 conversion, employs renewable electricity to convert carbon dioxide and water into renewable fuels and chemicals. This technology has three compelling advantages:
(1) It offers a tool for reducing CO2 emissions: emitted CO2 is captured and converted to chemical feedstock for plastics and other materials and is permanently stored (carbon negative), while fuels generated this way are mostly carbon neutral because burning them simply re-releases the CO2 used to create them.
(2) It provides a solution to large-scale and long-term storage of intermittent renewable energy: highly variable renewable electricity from wind and solar is transformed into gas and liquid fuels which can be readily stored and transported with current infrastructures.
(3) It enables sustainable production of chemicals and materials: chemicals and materials such as plastics can be produced from sustainable resources (CO2 and water) instead of depleting fossil-based feedstocks. The practical application of electrochemical CO2 conversion requires high performance in several figures of merit, including reaction rate, product selectivity, energy efficiency, and system stability. These performance metrics govern not only the capital and operational costs of the process, but also the carbon footprint of the products from CO2. Currently, these performance metrics remain far below those needed for practical application. Often only one or two of these key performance indicators is matched for potential practical application; seldom are all of them. We have developed new electrochemical CO2 conversion systems that enable achieving high performance in all key metrics to advance this technology.
What inspired or motivated you to work on your current research or project?
At the heart of my work is a desire to enable a truly sustainable world where everyone from anywhere has access to clean energy, water and food. Fuels and chemicals such as fertilizers for agriculture development are among the key components enabling that sustainable world. Currently, fuels and chemicals are produced from fossil-based feedstocks. Burning these fuels and producing those chemicals account for more than 80% of total CO2 emissions – the main cause of global warming and climate change. More importantly, current fuels and chemicals are highly geographically constrained, making them less accessible to everyone. I envision producing carbon-neutral fuels and chemicals, typically made of carbon (C), oxygen (O), and hydrogen (H), directly from CO2, water and renewable electricity. Since CO2, water, and renewable energy are highly abundant and available almost everywhere, making fuels and chemicals from these elements offers a compelling path toward a sustainable world. The challenges are: CO2 is a very stable molecule and the CO2 conversion process is very complex. Careful attention to many technological aspects is required when developing this technology. A few years ago, I began working on electrochemical CO2 conversion technology at the University of Toronto. During that time, we successfully developed the most stable system for CO2 conversion to ethylene, a precursor for plastic production. We also pushed the boundary limit for ethylene production rate by further optimizing the electrode – the heart of the electrochemical CO2 conversion system- which converts CO2 molecules to desired products. While we made significant progress in many performance metrics for CO2 conversion, our system suffers from CO2 loss to byproduct – a process that requires a significant additional amount of energy recovery. Since joining Queen’s University, my research group has started to explore electrochemical systems that can avoid CO2 loss. More importantly, we aim to develop systems that allow integrating carbon capture and conversion in a single step to reduce the overall energy requirement for the two steps. Recently, we made a significant step toward this goal by developing a highly efficient electrochemical CO2 conversion system, which is very similar to CO2 conversion from a captured solution in the integrated system.
In what ways does society benefit from your research?
Climate changes have been affecting human life in many ways. We have been seeing more extreme and unpredictable weather events, which have negative impacts on human health, the physical environment and the global economy. Reducing CO2 emissions is urgently needed to limit the global temperature from increasing and minimize the devastating effects of climate change. Reducing greenhouse gas emissions means transitioning away from fossil fuels and decarbonizing all industries. This is significantly challenging because we currently emit around 40 billion tons of CO2 every year. While the majority of this amount could be avoided by the widespread deployment of renewable energy, carbon emissions from long-distance transportation and heavy industries including chemicals, steel, and cement are very difficult to mitigate because they require high energy density fuels. To achieve net-zero emissions, carbon capture and conversion will play an essential role because this technology is the key to hard-to-decarbonize transportation and heavy industry sectors. We envision that even when net-zero carbon emissions are achieved, billions of tons of CO2 would be removed from industrial process and the atmosphere annually. The conversion of CO2 to valuable products would provide economic incentives to accelerate carbon capture and utilization technology. The carbon-neutral fuels produced from CO2 and renewable electricity can be readily integrated into current infrastructures for long-term storage and transportation.
Looking ahead, what are your hopes or aspirations for the future based on your research or project?
Currently, we have demonstrated the concept that highly efficient CO2 conversion can be achieved using a liquid solution containing CO2. Our next step is to advance the CO2 conversion directly from a capture solution. This will help us realize integrated CO2 capture and conversion technology. Also, we are now producing simple fuels and chemicals such as methane and ethylene. Our next step will be focusing on more complex molecules, such as urea, a fertilizer, directly from carbon dioxide and nitrogen. As an engineer, scaling up our technologies is always one of the most exciting parts of my research. We plan to work with various collaborators and industrial partners to scale up the processes we develop in the lab and accelerate the development of CO2 capture and conversion technologies.