Electric avenue: researchers use electric fields to catalyse chemical reactions

Article by Adam Duckett

WHAT if you could one day catalyse your industrial reactions with electric fields rather than the chemical catalysts commonly used today? It might be closer than you think after chemists at Kings College London successfully demonstrated the technique inside a microfluidic reactor.

The researchers say their experiment opens the door to a cleaner alternative to the catalysts used today and could transform the way chemicals are produced. Many of the catalysts currently used by industry are made of metals whose production is costly and highly polluting, such as iron, nickel, and platinum.

Ismael Diez-Perez, project lead and professor of chemistry at King’s College London, said: “Using electric fields as the only catalyst for chemical reactions has long been theoretically predicted. The idea came from scientists studying the mechanisms of enzymatic catalysis in nature, who predicted that large electric fields within the enzyme’s active sites could be acting as a catalyst in enzymatic chemical reactions.”  

Building on earlier research at smaller scale, the team built a microfluidic reactor through which they pumped a continuous flow of reactants. At the centre of the reactor, they created a space for reactions measuring just a few square centimetres by sandwiching together two gold-coated glass electrodes separated by a 250 µm gap.

King's College London
A close-up view of the microfluidic reactor

The experiments involved pumping the reactants through the gap between the electrodes with the electrodes turned on. And then pumping the reactants through with the electrodes off and instead using copper ions to catalyse the reactions. They found the electric field worked as a “fine control knob” to help manipulate the reaction yield. It increased by 22% and 197% respectively at voltages of 1.5V and 2+V, compared to using a metal catalyst.

They then investigated what difference it would make if they didn’t pump the reactants through the reactor while the electric field was turned on. They found that the reaction yield was 87% larger when circulating the reactants, showing enhanced mass transfer under continuous flow.

Diez-Perez and his team believe this process could transform the manufacture of pharmaceuticals which typically relies on the production of very fine, value-added chemical compounds. These are normally highly expensive to produce through traditional catalysis methods. The team predicts that electric fields could also help manufacturers control the formation of pure isomeric chemical compounds, which would help industry reduce costly separation techniques.

Diez-Perez said: “This breakthrough signals the start of a very exciting step change in transforming the way we manage catalysis. We have now proven that electrical fields can be scaled up to produce milligrams of chemical compounds. The next step is to build even larger models for use across many different fields and industries – enabling cheaper, greener production methods.”

The research is published in Nature Communications.

Article by Adam Duckett

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