11 January 2019

Emissions of carbon dioxide dramatically reduced in new chemical production process

Chemists at Utrecht University have managed to utilise cobalt as a catalyst for the production of basic chemicals from natural gas. In doing so, they have reduced the carbon dioxide emissions in a vital step of the chemical conversion process from 50 per cent to almost zero. Nature Communications published the findings by the group of inorganic chemists led by Krijn de Jong today.

The chemical industry uses basic chemicals made from petroleum for the large-scale production of plastics, pharmaceuticals, and solvents. In the process, considerable energy is lost as the long carbohydrate molecules that petroleum is made of are cut into smaller pieces. The transition to natural gas and biomass as raw materials is now in full swing. One possible reaction path in that transition uses iron as a chemical catalyst, but at the moment the process loses around 50% of the carbon in the form of CO2.

Cobalt instead of iron

A former PhD candidate at Utrecht University’s Debye Institute for Nanomaterials Research has discovered that CO2 emissions can be reduced to zero when she used modified cobalt to catalyse the reaction instead of iron. UU inorganic chemist Krijn de Jong: “This is a breakthrough in catalysis science, and it has everything to do with the size, shape, crystalline structure, and surface composition of the cobalt nanoparticles.”

Krijn de Jong

Essential sodium and sulphur particles

Via the intermediate product ‘synthesis gas’, a mixture of carbon monoxide and hydrogen, the circumstances can be optimised to create light olefins. In the older reaction using iron as a catalyst, 50% of the synthesis gas had a tendency to change into carbon dioxide, and part of it converted back into methane. But when cobalt is used as a catalyst, almost no carbon dioxide is created, and very little methane. De Jong: “That’s because the surface holds particles of sodium and sulphur, which are essential for suppressing the formation of methane.”

Major leap forward

Scientists are still unsure why the process suppresses the production of CO2, however. De Jong: “Answering that question will require some more scientific research. But the result is a major step towards the commercial application of cobalt as a catalyst for the production of basic chemicals.” Former PhD Candidate Jingxiu Xie, the first author of the publication, now works at BasCat, a joint lab operated by chemical giant BASF and the research cluster UniCat in Berlin.

 

Publication

Promoted cobalt metal catalysts suitable for the production of lower olefins from natural gas

Jingxiu Xie, Pasi P. Paalanen, Tom W. van Deelen, Bert M. Weckhuysen, Manuel J. Louwerse & Krijn P. de Jong

All authors affiliated with Utrecht University.

Nature Communications, 11 January 2019