Lab profile: Paula E. Colavita, Trinity College Dublin

Interfacial reactions, particularly those that occur at the surfaces of disordered materials, are central to environmental chemistry, biodevices, and catalysis. Paula E. Colavita at Trinity College Dublin is interested in understanding these reactions better in order to design interfaces that enable their control. In particular, she has always had a great interest in the study of carbon interfacial chemistry in general and, more particularly, the applications of advanced carbons in different fields from biomaterials to electrocatalysis.

She studied Chemistry at the University of Trieste and received a PhD in Physical Chemistry from the University of South Caroline in 2005. Following post-doctoral research work at the University of Wisconsin-Madison, Paula joined Trinity College Dublin in 2008. In 2021, she gave the Materials Today ‘Materials in Society’ Lecture (www.materialstoday.com/materials-in-society), which highlights how materials science is tackling real world issues and make a difference to how humans live and work.

Paula talked to Materials Today about her current research and future plans.

How long has your group been running?

I joined Trinity in 2008 and my group has developed from two students then to its current size of 11 researchers now. We are based at the School of Chemistry in Trinity College Dublin, in the heart of the city on a beautiful historic campus that is one of the most-visited sites in Ireland.

How many staff currently makes up your group?

Currently, my group consists of 11 researchers: four postdocs, four PhD students and three undergraduates. We often host researchers from other universities particularly over the summer months and this has been a very enjoyable way of building links with other groups and universities across Europe and the US.

What are the major themes of research in your group?

My group’s work aims at understanding and controlling reactions at carbon-based materials/nanomaterials interfaces with particular focus on those based on non-crystalline and amorphous phases. Carbon materials are ubiquitous in applications ranging from biomaterial coatings to electrodes, however in-depth knowledge of factors controlling their interfacial chemistry is needed to harness their properties for advanced applications. I have applied and developed synthesis, modification, and characterization strategies to elucidate structure/reactivity relationships, focusing on reactions involving charge-transfer at the carbon/liquid interface. Charge-transfer, whether spontaneous, photoinduced, or promoted by applied potentials, underpins applications ranging from energy conversion to biosensing. Tools for rationalizing and predicting reactivity of disordered carbons are limited: my team aims at developing such tools and our research contributions have delivered new knowledge on descriptors that can guide the synthesis of nanostructured carbons with advanced functionality.

How and why did you come to work in these areas?

During my time as a postdoctoral researcher, I became interested in using amorphous carbons to improve understanding of reaction mechanisms that were at that time challenging to investigate on other crystalline carbon materials. Amorphous carbons can be synthesized with very smooth surfaces that avoid the complications of working with porous materials and make them amenable to advanced characterization methods. At the same time, they can be tailored to have different compositions and specific functional groups, as well as be deposited onto a variety of substrates. This struck me as an interesting opportunity to use amorphous carbons as a platform material with great tunability in terms of its surface chemistry to investigate fundamental reactions and identify useful descriptors of general value.

During my time at Trinity, my group has been able to demonstrate how versatile amorphous carbons can be as model systems for investigating interfacial reactivity. This versatility has proved extremely useful in the study of electrocatalysis in particular. We are interested in several carbon-based materials and nanomaterials, but amorphous carbons have remained a common theme and a very useful tool to tackle broader problems in reactivity of carbons.

What facilities and equipment does your lab have?

Our group has three main laboratories, but we also have access to common facilities across the Trinity campus. We have standard wet chemistry lab space for carrying out synthesis and modification of materials. Our core equipment includes a physical deposition system for reactive sputtering of carbon thin films with controlled composition. We have an infrared spectroscopy system for surface thin film characterization that we have adapted for both ex situ and in situ experiments, including spectroelectrochemistry. We have several workstations for electrochemical characterization, including voltammetry, impedance spectroscopy, and hydrodynamic methods. More recently, thanks to a collaboration with Dr. Kim McKelvey, we have started carrying out experiments using nanoelectrochemistry methods and we now look forward to exploring the electrochemistry of our carbon materials with nanoscale resolution.

Do you have a favorite piece of kit or equipment?

It is difficult to make a choice, but I return time and again to our infrared spectrometer. I find that getting a high-quality infrared spectrum of an organic film that is 1 nm or less in thickness is simply magical! Second in line is our sputtering system; it has been modified and adapted over the years and I remain impressed by its versatility.

What do you think has been your most influential work to date?

I believe our work on model carbon electrodes for investigating reactivity trends in the oxygen reduction reaction (ORR) was very original and said something new about this reaction. Model carbon thin films from my lab were used to understand the role of electronic and chemical effects of functional N-sites on the electrochemical response in the ORR. We were able to investigate the ORR as a function of pH and pinpoint the role of pyridinic versus graphitic sites in imparting activity to metal-free carbons. Notably, we provided unprecedented insight into N-site cooperativity that we believe affects selectivity in the ORR towards the full reduction to water/hydroxide. I think these insights will be very useful to guiding synthetic approaches towards the development of advanced and sustainable cathode materials, while also demonstrating the potential of model systems for obtaining mechanistic insights.

What is the key to running a successful group?

I would not say there is one single skill or approach that works but it is important to be flexible and adaptable in general.

Recruit good students and good researchers. When recruiting, I tend to look not only at individual potential but also at how different skills and scientific interests might fit together to strengthen the team as a whole, so that people can benefit from interacting with each other and work can progress in a collaborative manner.

Find good collaborators that you enjoy working with and who will nudge you out of your comfort zone. But is also important to find a balance between work that you drive independently and work that is done collaboratively.

If the group does experimental work, resources are very important and investing time in funding applications should be factored in as a core activity.

Finally, identify infrastructure risks to the progress of a research program early on and try to mitigate as best as possible.

How do you plan to develop your group in the future?

I think I will always have an interest in interfacial reactivity, but the areas of application on which we focus might change in the coming years. I am really enjoying the work we are doing now with nanoelectrochemical methods – so stay tuned for our upcoming work in this area! I am also keen to investigate electrochemical reactions for energy conversion applications that involve organics: there is a lot of interesting work that can be done in this field and the implications for sustainability are very exciting.

Key publications

1. J. M. Vasconcelos, F. Zen, M. D. Angione, R. J. Cullen, M. J. Santos-Martinez, P. E. Colavita. Understanding the Carbon–Bio Interface: Influence of Surface Chemistry and Buffer Composition on the Adsorption of Phospholipid Liposomes at Carbon Surfaces. ACS Appl. Bio Mater. 3 (2020) 997-1007. https://doi.org/10.1021/acsabm.9b01011
2. A. Iannaci, A. Myles, T. Flinois, J. A. Behan, F. Barrière, E. M. Scanlan, P. E. Colavita. Tailored glycosylated anode surfaces: Addressing the exoelectrogen bacterial community via functional layers for microbial fuel cell applications. Bioelectrochemistry 136 (2020) 107621. https://doi.org/10.1016/j.bioelechem.2020.107621
3. J. A. Behan, A. Myles, A. Iannaci, É. Whelan, E. M. Scanlan, P. E. Colavita. Bioinspired electro-permeable glycans on carbon: Fouling control for sensing in complex matrices. Carbon 158 (2020) 519-526. https://doi.org/10.1016/j.carbon.2019.11.020
4. J. A. Behan, E. Mates-Torres, S. N. Stamatin, C. Domínguez, A. Iannaci, K. Fleischer, M. K. Hoque, T. S. Perova, M. García-Melchor, P. E. Colavita. Untangling Cooperative Effects of Pyridinic and Graphitic Nitrogen Sites at Metal-Free N-Doped Carbon Electrocatalysts for the Oxygen Reduction Reaction. Small (2019) 1902081. https://doi.org/10.1002/smll.201902081
5. J. A. Behan, A. Iannaci, C. Domìnguez, S. N. Stamatin, M. K. Hoque, J. M. Vasconcelos, T. Perova, P. E. Colavita. Electrocatalysis of N-doped Carbons in the Oxygen Reduction Reaction as a function of pH: N-sites and Scaffold Effects. Carbon 148 (2019) 224-230. https://doi.org/10.1016/j.carbon.2019.03.052
6. F. Zen, V. D. Karanikolas, J. A. Behan, J. Andersson, G. Ciapetti, A. L. Bradley, P. E. Colavita. Nanoplasmonic Sensing at the Carbon-Bio Interface: Study of Protein Adsorption at Graphitic and Hydrogenated Carbon Surfaces. Langmuir 33 (2017) 4198-4206. http://dx.doi.org/10.1021/acs.langmuir.7b00612
7. J. A. Behan, S. N. Stamatin, M. K. Hoque, G. Ciapetti, F. Zen, L. Esteban-Tejeda, P. E. Colavita. Combined Optoelectronic and Electrochemical Study of Nitrogenated Carbon Electrodes. J. Phys. Chem. C 121 (2017) 6596-6604. http://dx.doi.org/10.1021/acs.jpcc.6b10145
8. F. Zen, M. D. Angione, J. A. Behan, R. J. Cullen, T. Duff, J. M. Vasconcelos, E. M. Scanlan, P. E. Colavita. Modulation of Protein Fouling and Interfacial Properties at Carbon Surfaces via Immobilization of Glycans Using Aryldiazonium Chemistry. Sci. Rep. 6 (2016) 24840. https://doi.org/10.1038/srep24840
9. D. Jayasundara, R. J. Cullen, P. E. Colavita. In situ and real time characterization of spontaneous grafting of aryldiazonium salts at carbon surfaces. Chem. Mater. 25 (2013) 1144–1152. https://pubs.acs.org/doi/10.1021/cm4007537
10. R. J. Cullen, D. Jayasundara, L. Soldi, J. Cheng, G. DuFaure, P. E. Colavita. Spontaneous grafting of nitrophenyl groups on amorphous carbon thin films: A structure-reactivity investigation. Chem. Mater. 24 (2012) 1031–1040. https://pubs.acs.org/doi/10.1021/cm2030262