For the first time ever, a team of researchers from the University of Southern California has provided evidence that carbon dioxide (CO2) can be captured from the air and directly converted into methanol (CH3OH). The process, which uses a homogenous catalyst, provides numerous benefits, including the removal of CO2 from the atmosphere and the production of methanol that has the potential to be used as an alternative to fuel gasoline.
"Direct CO2 capture and conversion to methanol using molecular hydrogen in the same pot was never achieved before. We have now done it!" Surya Prakas, co-author of the study, said in a press release.
Scientists have been attempting to find novel ways to recycle CO2 for years now, including treating it with hydrogen gas (H2) and methane (CH4), although methanol is the most attractive option due to its use as an alternative fuel. Furthermore, it is also used as a building block for larger compounds, which is why the chemical industry currently produces 70 million tonnes of it per year.
The most important factor in the CO2-to-methanol conversion process is pinpointing a good homogenous catalyst, which is essential to bolster the chemical reactions and allow the fast production of methanol. However, these reactions typically require higher temperatures and cause decomposition of the catalyst.
"Developing stable homogeneous catalysts for CO2 reduction to methanol was a challenge," Prakash said. "Majority of the catalysts stopped at the formic acid stage. Furthermore, we needed a catalyst that could reduce carbamates or alkylammonium bicarbonates directly to methanol. We have achieved both with our catalyst."
The new catalyst, in combination with a few additional compounds, allowed the team to show that 79 percent of the CO2 that they captured could be converted into methanol. They now plan to find methods of lowering the operating temperature of the catalyst in order to improve its efficiency.
"We will continue the studies to develop more robust catalysts that work around 100 to 120 °C," Prakash said. "We would like to perform the chemistry in a preparatively useful way, wherein there are no solvent or reagent losses."
The findings were published in the Dec. 29 issue of the Journal of the American Chemical Society.
