Enzymes use cascade reactions to produce complex molecules from relatively simple feedstocks. Researchers have already copied this principle.
An international research team has used nanoparticles to convert carbon dioxide into valuable raw materials. Scientists at the Ruhr-University Bochum in Germany and the University of New South Wales in Australia have adopted the principle of enzymes that produce complex molecules in multistage reactions. The team transferred this mechanism to metallic nanoparticles, also known as nanosheets. Chemists used carbon dioxide to produce ethanol and propanol, which are common raw materials for the chemical industry.
The team led by Professor Wolfgang Schuman of the Bochum Center for Electrochemistry and Professor Corina Andronescu of the University of Duisburg-Essen, together with the Australian team led by Professor Justin Gooding and Professor Richard Tilly, reported in the Journal of the American Society of Chemistry August 25, 201
"The transfer of cascade reactions of enzymes into catalytically active nanoparticles can be a crucial step in the design of catalysts," says Wolfgang Schumann.
Particles with Two Active Centers
Enzymes have different active centers for cascade reactions that specialize in specific reaction steps. For example, an enzyme can produce a complex product of relatively simple starting material. To mimic this concept, the researchers synthesized a particle with a silver core surrounded by a porous layer of copper. The silver core serves as the first active center, the copper layer as the second. The intermediates formed in the silver core then react in the copper layer to form more complex molecules that eventually leave the particle.
In the present work, the German-Australian team has shown that the electrochemical reduction of carbon dioxide can be accomplished using nanosomes. Several reaction steps on the silver core and copper shell convert the starting material into ethanol or propanol.
"There are other nanoparticles that can produce these CO products 2 without the cascade principle," says Wolfgang Schuhmann. "However, they require significantly more energy."
Researchers now want to further develop the concept of a cascade reaction in nanoparticles so that they can selectively produce even more valuable products such as ethylene or butanol.
Reference: "Cascade reactions in nanosomes: spatially separated active sites inside Ag-Core – Porous-Cu-Shell nanoparticles for multistage reduction of carbon dioxide to higher organic molecules" by Peter B. O'Mara, Patrick Wilde , Tanya M. Benedetti, Corina Andronescu, Soshan Cheong, J. Justin Gooding, Richard D. Tilley, and Wolfgang Schuhmann, August 25, 2019, Journal of the American Chemical Society .
doi: 10.1021 / jacs.9b07310