New materials to soak up carbon dioxide

Robyn Williams: Yes, still exploring connections, those between Britain and Australia, still much stronger than you may think in science. Take Dylan Sherman, once a young lawyer working in Sydney, now at Trinity College in Oxford, exploring chemical ways to tackle excess CO₂ in the atmosphere and other marvellous applications of materials science.

Dylan Sherman: Okay, so a lot of people are very well aware of metal salts like sodium chloride that sits on your kitchen table every day and they are very solid, rigid type materials made of these uniform atoms that bind very closely. In the opposite world you have things like the plastics that make your bags and containers that can be very flexible and malleable depending on how you want to use them. So I research in this kind of middle ground between these two extremes of the spectrum, in these materials called metal organic frameworks. So they combine the power of these crystalline metals that sit at the corners of cubes, and between those corners we connect the atoms using organic linkers, almost like rubber bands that connect between the ends of two sticks. When we do that, we can create these really interesting ordered materials that expand in all directions but in a predictable way, leading to a structure that is highly porous inside but still rigid and predictable, and that pore space is quite amazing. We have in about a teaspoon, so a gram of this material, 7,000 approximately metre squared per gram of space. So if you take a teaspoon, that's almost a football field's area of surface area that we can access.

Robyn Williams: And can you access it?

Dylan Sherman: Absolutely. So we haven't tried, other people in the field have been trying it for the last 25 years and they've certainly reported incredibly successful results where you can access and harness that surface area quite effectively, and immediately you might wonder why do we want such a large amount of surface area in a pore? Well, think about your kitchen sponge sitting on your table in the kitchen, if you put that in water it will absorb a massive amount of water for the relative size and space of that sponge. We are doing the exact same thing with these materials except these are solid crystal materials, and rather than absorbing water we can look at absorbing gases, let's say carbon dioxide…

Robyn Williams: Ah, CO₂! Could you?

Dylan Sherman: We absolutely could, and there has been a lot of proof of studies done already and some companies trying to scale up at the same time and looking at how we can get a very large amount of CO₂ absorbed from atmospheres or from different industrial applications into these materials and then they can be potentially catalysed or reacted within the material so that the output is environmentally friendly and benign, be that something just like water.

Robyn Williams: You mentioned 'scale up' just now, in other words you can do it on a small scale, but what do you have to do to get to it on a large scale, to take the CO₂ out of the air as we need it to be taken?

Dylan Sherman: That's a very good question, and I think the field is still very much exploring how that's possible. Anything at the micro level can work one way at the moment you try to scale up you have a whole different world of science you have to deal with. It's not comparable at all. So you need to start to work out, one, a synthetic route that is going to not produce a large amount of waste because as you scale up there will be a massive amount of waste in comparison to your product. You've then got to find a relatively energy favourable process as well, and then you need to be able to have reagents that can be purchased in such a large scale as well. So, many companies are working on that now and some of our original materials, 20 years old, can be scaled up, but we want materials that are more rigid, more interesting. So our group is specifically looking at how we can get more interesting properties out of these and then hopefully scale up further later on.

Robyn Williams: And that is your DPhil, that is your doctorate going on now, is it?

Dylan Sherman: Absolutely, yes. So we are looking kind of more specifically at how can we make these materials as thin as possible. So if you imagine a large bulk pile of powder, you can't access a lot of the material within the centre of it, and you are relying basically on diffusion, so material pushing through that large pile of powder to get to the centre. We want to take it a step further and ask can we produce incredibly wafer-thin crisp nano-sheets of these materials which would be…let's say we are talking one nanometre thin, which is 10^-8 metres, so that's almost a million sheets that you could stack in the space of one metre. And the point of that would be to maximise our surface area of the material that is open to the environment, while still allowing for a very thin film of that material at the base. So these are very temperamental, if you imagine a nice wafer crisp thin biscuit, they will crack immediately compared to a good old Arnott's biscuit that might hold on. So the question is how can we make those stable and reliable and not fragile when they are out in the real world?

Robyn Williams: Yes, mentioning the biscuit, Arnott's, of course gave it away straight away, you are from Australia and you are here on a particular award.

Dylan Sherman: Of course, yes, so I'm from Sydney and I came over here only in 2020 on the gracious funding from the Sir General John Monash Foundation in Australia which elects roughly 10 to 20 wonderful people from all around Australia leading in various different fields, and they encourage us to go off and learn and expand our horizons so we can potentially gain those skills for leadership in the future.

Robyn Williams: Wonderful, and of course by definition that includes you, and despite the fact (and this is astonishing) you are working not as a scientist but as a lawyer. Lawyers can be wonderful. But how come?

Dylan Sherman: Absolutely. I started with science actually for one year back when I started university in 2013 at the University of Sydney, and I felt there was something missing, I wanted to connect more to society, to commerciality, to the world, and find a way to bridge that gap between what is often quite insular logic and discovery in science to the real world. And I thought law might be the way to do that. So I started to do legal studies as well, finished about, started to work for a while at a corporate firm in Sydney as well doing a lot of intellectual property-type work and starting to realise that there is a huge benefit having two perspectives, not only the technical knowledge but also that rigorous corporate, commercial and societal understanding so that you can connect those dots and the work that you do in lab more realised and accessible to the world.

Robyn Williams: And your ambition is to come back to Australia, presumably to show people how to use those substances that you mentioned to remove CO₂ from the atmosphere and save us all.

Dylan Sherman: I would love to do that, in a very, very optimistic world. But even more specifically I think as part of that is coming back, sharing that knowledge with other lab groups and then maybe getting onto the policy side and asking ourselves beyond just making these materials how can we support the development of these materials and the integration of these materials through some resilient policy in changing times.

Robyn Williams: One of the most interesting things being done in one area of Australia is the study of collaboration and how it makes the whole process of what you just described more efficient because lawyers or even farmers talking to scientists, and so on the story goes, is a great way to find out what's really needed rather than just being narrow.

Dylan Sherman: Totally, and I think I have to mention a few wonderful initiatives back at my old alum Sydney Uni where they've started to combine science not by original discipline but by topic, an area of concern. So if you are dealing with medicine, if you're dealing with nanoscale materials, there is a hub that integrates all the different sciences for that. And over in Europe I've had wonderful opportunities to connect with a large number of collaborators, and by using their expertise and their areas of knowledge, combining that together you can often overcome some challenges that just on your own is certainly not possible.

Robyn Williams: So you are looking at this rather complicated world with all its challenges and uncertainties in an optimistic way?

Dylan Sherman: I think so, I think you always need to have a positive outlook and be forward-thinking. I used to do this program called Future Problem Solving when I was young and they had two principles, one is 'the sky's the limit' and 'always be creative'. And where you think there is an opportunity there is probably a way to make it if you find the scientists who are determined enough to make it possible in the lab.

Robyn Williams: Who was that program with?

Dylan Sherman: Actually it's an independent charitable program called Future Problem Solving. I've been really lucky to stay on board now, so I've gone through the levels of coaching, through now to doing some more administration and board work in the international group in America. It's an accessible program, all the way from primary school up to early university levels and it's really asking people to use problem-solving skills to tackle some of the global issues that we might face in 20, 30 years, be that something like accessing freshwater supply, through to mining, which is actually the topic we are doing at national championships in just a few months in Australia, to more societal issues like education disparity. So it's a very diverse program but it makes people think diversely and work out how to solve problems in a way that may not just be done by looking at your academic literature.

Robyn Williams: Are there many people who've got your sense of purpose, studying here at the University of Oxford?

Dylan Sherman: Without a doubt I think. Everywhere is inspiring and you walk around each day and I meet a new person every day that I want to be just like or take something, take a quality of. If there is one takeaway I have as I move forward in life it's value the people around you and value what they stand for because they make you a better person at the end of the day.

Robyn Williams: Thank you and congratulations.

Dylan Sherman: Thank you very much Robyn.

Robyn Williams: Dylan Sherman, doing his doctorate at Trinity College in Oxford, a John Monash scholar.