18 JULY 2019

Turning the greenhouse gas, CO2, back into fuel

Inspirational Cambridge Scientists – Demelza Wright, the physicist

In the first instalment of interviews with University of Cambridge scientists, we spoke to Taylor Uekert about her work turning plastic waste into fuel with sunlight. Now, in the second post of the series, Demelza Wright from the Department of Physics at the University of Cambridge talks about why she became a scientist and describes how she is working to turn the greenhouse gas, carbon dioxide (CO₂), back into fuel. 

If you had asked me at the age of 13 about what I wanted to do for a job, I'd have said I wanted to be a musician. This is because I had decided I wasn't a good enough actor to star in Harry Potter, which had been my career of choice up until that point. When I was around 14 or 15 years old, I stumbled upon NewScientist magazine and it set me off on the path that eventually led me to become a researcher in physics.

Until I read that magazine, I had no idea what it meant to be a scientist or even what science was outside of the classroom. What really stood out to me was that these scientists were not simply measuring and understanding the world around them, but actually shaping it. They were doing things like making quantum computers or building robots to go into space. We need only to look at the success of the polio vaccine to see how science has changed the future prospects of millions of people worldwide.

So how best to shape the future from now? We know that the burning of fossil fuels is having a large impact on climate change. Alternatives to fossil fuels are vast and there are many talented scientists and engineers working on making them better. However, there is a large amount of greenhouse gas already released into the atmosphere. I am working on a way to turn one of those gasses, CO₂, back into fuel.

There are different materials that can turn CO₂ into fuel, and it would be useful to know exactly how they work so that we can tweak the materials to be more efficient and last longer. I am using a technique called Surface Enhanced Raman Spectroscopy (SERS) to investigate the materials.

To do SERS, I shine a laser on a material. This gives it some energy and causes all the different parts of the material to shake and vibrate. When I look at the light that comes back out of the material, I can see that some of it has changed colour – these colours show me which chemical bonds have been vibrating in the material. This is useful because the conversion of CO₂ to fuel happens by a chemical reaction, which is the breaking and making of bonds. Using SERS I can 'watch' the conversion of CO₂ to fuel and identify if and how the material changed along the way.

Science is a team effort, so once I know how the material is changed, I can talk to my colleagues in the chemistry department and ask them to alter some very specific aspect of the material to make it longer lasting. The balance of individual investigation and teamwork makes me glad that I chose to become a scientist.

My journey into research wasn’t always smooth, and I came pretty close to dropping physics during my A Levels. I decided to stick it out for the first year and I am glad that I did! I discovered that there is a lot of variety within physics and for every dry equation I had to memorise, there was a new world of fundamental particles or astrophysics to discover. The idea that 'not all scientists wear white coats' is true; for anyone who finds science interesting, there are some area of research that will suit you perfectly, even if they aren't the first thing that you come across. In my case, I’m happy helping to reduce CO₂ by studying materials with lasers.

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Demelza is performing research into chemical reactions at the nanoscale in the NanoPhotonics centre at the University of Cambridge. She uses the interaction of light with materials to probe and exert control over these systems for her PhD research.