A new class of atomically dispersed nickel catalysts directly converts captured carbon dioxide (CO2) to methane (CH4), according to Dr. Tomaz Neves-Garcia, a postdoctoral researcher at the Ohio State University, and his colleagues.
Direct electrochemical reduction of carbon dioxide capture species, i.e., carbamate and (bi)carbonate, can be promising for carbon dioxide capture and conversion from point-source. Image credit: Neves-Garcia et al., doi: 10.1021/jacs.4c09744.
Carbon dioxide is a greenhouse gas that accounts for a large part of Earth’s warming climate, and is produced by power plants, factories and various forms of transportation.
Typical carbon capture systems aimed at reducing its presence in the atmosphere work to lower carbon dioxide emissions by isolating carbon dioxide from other gases and converting it to useful products.
However, this process is difficult to implement on an industrial scale due to the massive amount of energy required for these systems to operate.
“Now, using a special nickel-based catalyst, we have figured out a way to save much of this precious energy by turning captured carbon dioxide directly into methane,” Dr. Neves-Garcia said.
By employing nickel atoms laid out on an electrified surface, Dr. Neves-Garcia and co-authors were able to directly convert carbamate, the captured form of carbon dioxide, to methane.
They found that nickel atoms, a cheap and widely available catalyst, were extremely good at making this conversion.
“We are going from a molecule that has low energy and producing from it a fuel that has high energy,” Dr. Neves-Garcia said.
“What makes this so interesting is that others capture, recover and then convert carbon dioxide in steps, while we save energy by doing these steps simultaneously.”
Most importantly, streamlining the carbon capture process helps reframe what scientists know about the carbon cycle, and is a vital step to setting up more complex strategies for faster and more efficient climate mitigation technologies.
“We need to focus on spending the lowest energy possible for carbon capture and conversion,” Dr. Neves-Garcia said.
“So instead of performing all the capture and conversion steps independently, we can combine it in a single step, bypassing wasteful energy processes.”
“Although many carbon capture methods are still in their early stages, with researchers from an array of fields working to improve them, the field is a promising one.”
“Converting carbon dioxide into a fuel using renewable electricity has the potential to close the carbon cycle.”
“For example, when methane is burned to generate energy, it emits carbon dioxide, which, if captured and converted back to methane, could lead to a continuous cycle of energy production without adding to Earth’s global warming burden.”
The study also represents the first time that researchers discovered they could use electrochemistry to achieve carbamate conversion to methane.
Although many attempts have been made to convert captured carbon dioxide into useful products, until now most researchers have only shown the ability to produce carbon monoxide.
“Methane can be a really interesting product, but the most important thing is that this opens a path to develop more processes to convert captured carbon dioxide into other products,” Dr. Neves-Garcia said.
The team’s work was published in the Journal of the American Chemical Society.
_____
Tomaz Neves-Garcia et al. 2024. Integrated Carbon Dioxide Capture by Amines and Conversion to Methane on Single-Atom Nickel Catalysts. J. Am. Chem. Soc 146 (46): 31633-31646; doi: 10.1021/jacs.4c09744