Building better catalysts to close the carbon dioxide loop

The best way to stave off the worst effects of climate change is to reduce CO2 emissions around the world. And one way to do that, says Zhongwei Chen, a professor in the Department of Chemical Engineering at the University of Waterloo, is to capture the CO2 and convert it into other useful chemicals, such as methanol and methane for fuels. Stopping emissions at the source, and further reducing future ones by replacing CO2-producing fuels with cleaner ones “…is a way to close the circle,” Chen says.

In order to turn CO2 into methanol, you need a catalyst to jump-start the electrochemical reaction. Traditionally, these catalysts have either been made out of precious metals like gold or palladium, or base metals like copper or tin. However, they are expensive and break down easily, hindering large-scale implementation. “Right now we can’t meet industrial requirements,” says Chen, who holds a Canada Research Chair. “So we are trying to design catalysts with better activity, selectivity, and durability.”

Read more on the CLS website

Image: Chithra Karunakaran on the SM beamline at the Canadian Light Source

Credit: David Stobbe

Reaction insights help make sustainable liquid fuels

Methanol, produced from carbon dioxide in the air, can be used to make carbon neutral fuels. But to do this, the mechanism by which methanol is turned into liquid hydrocarbons must be better understood so that the catalytic process can be optimised. Now, using sophisticated analytical techniques, researchers from ETH Zürich and Paul Scherrer Institute have gained unprecedented insight into this complex mechanism.

As we struggle to juggle the impact of emissions with our desire to maintain our energy hungry lifestyle, using carbon dioxide in the atmosphere to create new fuels is an exciting, carbon neutral alternative. One way to do this is to create methanol from carbon dioxide in the air, using a process called hydrogenation. This methanol can then be converted into hydrocarbons. Although these are then burnt, releasing carbon dioxide, this is balanced by carbon dioxide captured to make the fuel.

To fully develop this sustainable fuel, a deeper understanding of the mechanism by which methanol – in a reaction catalysed by zeolites, solid materials with unique porous architectures – is turned into long chain hydrocarbons, is necessary. With this in mind, in the frame of NCCR Catalysis, a Swiss National Center of Competence in Research, researchers from ETH Zürich joined forces with researchers from the Paul Scherrer Institut PSI to reveal the details of this reaction mechanism, the findings of which are published in the journal Nature Catalysis.

“Information is key to developing more selective and stable catalysts,” explains Javier Pérez-Ramírez, Professor of Catalysis Engineering at ETH Zürich and director of NCCR Catalysis, who co-led the study. “Prior to our study, despite many efforts, key mechanistic aspects of the complex transformation of methanol into hydrocarbons were not well understood”.

The researchers were interested in comparing the methanol to hydrocarbon process with another process: that of turning methyl chloride into hydrocarbons. Oil refineries frequently burn large quantities of unwanted methane rich natural gas. This polluting and wasteful activity results in the typical flares associated with oil refineries. “Turning methyl chloride into hydrocarbons is a kind of bridge technology,” explains Pérez-Ramírez. “Of course, we would like to move away from fossil fuels but in the meantime this would be a way to avoid wasting the vast reserves of valuable methane”.

Read more on the PSI website

Image: Researchers (L to R) Javier Pérez-Ramírez, András Bödi and Patrck Hemberger at the Swiss Light Source SLS

Credit: Paul Scherrer Institute / Markus Fischer