Til bevillingsoversigt

Electrochemical Halide Coupling to Hydrocarbons

Carlsberg Foundation Young Researcher Fellowships

What

This project is about electrochemically converting alkenes (e.g. ethylene) and halide salts (e.g. NaCl) to halogenated hydrocarbons. While we now know how to electrochemically convert CO2 to molecules such as ethylene, the next step is to add functionality by attaching chlorine, bromine, or fluorine to make materials such as PVC piping, flame retardant clothing, Teflon and many other practical goods.

This project will understanding how both the alkene and the halide bind to a catalyst surface and how these two species interact with each other. We will then work to design catalyst that have optimally binding to both species, thus allowing for alkene-halogen coupling.

Why

The current process of halogenating alkenes is both inefficient and needs to have a toxic halogen gas as a reactant for the reaction. An electrochemical approach allows for a much more efficient method to producing halogenated alkenes. Furthermore, this approach has the possibility to use table salts such as NaCl rather than chlorine gas, which greatly reduces safety concerns.

From a more fundamental aspect, we have only been able to couple hydrogen and oxygen to carbon electrochemically, and if this project can successfully allow halide coupling to carbons, this will greatly enhance our understanding of electrochemical processes allowing for further discoveries to be made.

How

To understand how the halides and alkenes bind to the catalyst we will vary the potential of the catalyst and monitor adsorption and desorption from the catalyst surface. Monitoring a single layer adsorbing/desorbing on an electrocatalysts needs highly precise measurement tools and a recent DTU spin-out, Spectroinlets, has developed a tool just for this purpose.

For testing optimized electrocatalsyts we will use a fuel cell/electrolyzer approach to allow for optimal mass transfer of gaseous alkenes as well as aqueous based halide salts. This scaled up approach will provide sufficient products to allow for us to determine main products as well as smaller products, thus helping us elucidate mechanistic pathways to products.

SSR

As the world converts more and more of its processes to electrical based processes, it is essential that we understand electrochemical based catalysis. Understanding how carbon and halides can be combined via an electrocatalysts allows for the potential to use this approach to buffer intermittent renewable energy, develop a more energy efficient process, and create a safer, more benign process to produce halogenated hydrocarbons.

Furthermore, an electrochemical approach is easily downscalable, which allows us to produce halogenated hydrocarbons using an in-situ, decentralized approach. This can greatly reduce excess production waste and shipping, both of which currently contribute significantly to environmental degradation.