Glückwunsch, Dr. Geiger!

Julian Geiger, a PhD student who is under Prof. Núria Lopez’ supervision, has successfully defended his PhD thesis entitled “Ceria-Based Single-Atom Catalysts: From Simplified Models Towards Real-World Complexity” publicly on October 13^th.

The members of the evaluation committee were Prof. Nicola Marzari (École Polytechnique Fédérale de Lausanne (EPFL), Switzerland), Prof. Livia Giordano (University of Milano-Bicocca, Italy) and Dr. Albert Bruix Fusté (University of Barcelona).

Dr. Geiger is from Schwabach, Germany. He studied chemistry at the Friedrich-Alexander University Erlangen-Nuremberg, with short stays in Cambridge and BASF along the way. Then Julian got the FI grant from the Catalan government to do the PhD at ICIQ. In his free time, he likes to do sports, meet friends and enjoy music.

Why did you become a scientist?

I find the world absolutely fascinating. From the very small, to the very big. Just think about the wonders of the cosmos – or how 80 billion neurons form our consciousness, the greatest mystery of all. My parents told me that as a child, I was always questioning everything, never shutting up asking “why”? It has been this very fundamental interest of mine, to explore and understand the world, that has driven me to become a scientist.

What do you want to achieve as a scientist?

Apart from personal curiosity, I would also like my work as a scientist to have a positive impact on the world. What else has been the driving force behind the improvements in our lives over the last few centuries, if not science and technology? Therefore, I see it as a very noble cause.

What is your thesis about?

My thesis is about ceria-based single-atom catalysts, which I studied with computational methods. In particular, I was looking at dynamic electronic effects that occur at the minuscule scale of single atoms.

What triggered your interest for the subject of your thesis?

Heterogeneous catalysis is what drives the chemical industry, especially for simpler, bulk chemicals. Here, (reducible) oxide supports, such as ceria (the main material of my thesis) are ubiquitous. Within the field, the use of single-atom catalysts presents a promising new approach that has only been around for about a decade, so it’s really cutting-edge research at the frontier of human knowledge. Lastly, I always found the theoretical treatment of atomic systems the most intriguing, as these theories allow one to gain understanding at a very fundamental level. This is also the reason why I chose to become a computational chemist.

What applications can your thesis have in the future?

I do hope that the insights about dynamic effects occurring in the systems I studied will be useful for synthesizing, fine-tuning, and understanding novel single-atom catalysts. I think this is nicely showcased by two real-world catalysts that we investigated, where we could provide our experimental collaborators with helpful chemical insight into why their systems behave the way they do.

What will you miss the most from ICIQ?

The people. I met so many beautiful souls here, and I am incredibly grateful for all the friendships I have made.

What advice do you have for someone who’s starting their PhD now?

Take it easy. Don’t worry too much. Just give your best every day and try to continuously improve. You’re doing great. You’ll be fine.

Have you ever been emotional over an experiment/simulation? Why?

Of course. Most people who do a Ph.D. have great passion for what they do. If things don’t work out, it affects you on a personal level. It’s something you take home with you when you leave the lab. For me, my first project at ICIQ, a project that involved Machine Learning (ML) was quite difficult to master. As I have not been trained on the topic, I didn’t really know where I was going wrong. Was it the chemistry, the theoretical models, the ML? Too many factors at once. Eventually, I could solve it, and I picked up many strategies along the way. For example, simplifying things. Better to start with just a little data, to get the ML to work, rather than directly diving in with the thousands of actual data points of the project. It’s important to be clever in the way you approach things. Don’t try to solve everything at once, it’s easy to get lost otherwise.

Who has been your biggest influence?

Well, my boss, Prof. Núria López, definitely had the biggest influence on my development into an independent scientist during these four years of Ph.D. Especially when you’re young and you start anew (such as I did in the group), you might be a bit naive. You might think you know everything better already, because you don’t even know all the things you don’t know. However, now, after four years, I see myself starting to preach the same things she was preaching to us when we started. So, take the advice of your seniors to heart, they might have a point (at least initially – then, you can still discard it if you don’t agree).

Where are you going next? What will you do there?

I’m super happy that I got accepted as a Postdoc at the Paul-Scherrer Institute in Switzerland, where I’ll be working as a Software Engineer. That means I won’t be doing the science myself anymore, but I’ll assist others with theirs, mainly by writing code. I found that to be the most fun and what I’m best at. It’s also a bit of a different direction, so there will be much to learn. Very exciting!

What is your favourite molecule? 

I’d say tryptamine, as it provides the basis for various neurotransmitters that are crucial for our perception of the world.

If you were a piece of lab equipment, what would you be?

A “Central Processing Unit”, or commonly known as a CPU, the “brain” of a computer, so to speak. It’s a marvelous piece of technology, a testament to human ingenuity, and where my chemistry of the last four years has actually played out.