Michael Nolan shares his path to Research Excellence

Michael Nolan is a Principal Scientist at Tyndall National Institute, where he leads the Materials Modelling for Devices activity in the MNS Centre. This is a group of PhD and postdoctoral researchers using state of the art simulations to model new materials and their processing for a range of technologies. These include renewable energy, carbon dioxide conversion, new materials in electronics and materials for medical devices.  This group is among the largest users of Tyndall’s local high performance computing facility and the national supercomputing service, provided by ICHEC.

I obtained my PhD in 2004 from UCC in Microelectronic Engineering, having graduated with a BSc. In Chemistry and German from DCU in 1997 and an MEngSc in Electronic Engineering from UCC in 1999, and I have been at Tyndall since 2005.

I became interested in modelling as a result of taking classes on quantum mechanics and how this is applied to chemistry and found that I enjoyed this topic and had some aptitude for it. Unfortunately, I was not so skilled in the laboratory, so focusing on modelling was a good fit for me. I spent two semesters in Leipzig, Germany, as a student and there I learned how we can use modelling to understand chemistry.

We have a range of projects supported by Science Foundation Ireland, European Commission, Enterprise Ireland and Industry. These cover areas from new materials in electronic devices and how to process these materials, new materials for hydrogen production from water and carbon dioxide conversion to useful chemicals, and how to process solid materials and hybrid inorganic/organic materials. We have significant links with many experimental groups in Tyndall, Europe, USA and China and I believe that the work we do is only of value when combined with experimental work to demonstrate our new materials. Industry is also hugely interested in our expertise in simulation of materials, their processing and our experimental links.

 

Deep Expertise & Internationally Recognised Leadership in Modelling

We have developed significant, internationally recognised leadership in the modelling of surfaces, interfaces and chemistry of materials. As examples to showcase this, we highlight the following:

Our work on vacancies in cerium dioxide, which is widely used in automotive catalysis, fuel cells and as a dielectric, are recognised as landmark papers in the field and continue to be highly cited with over 600 citations each. This enabled me to build my reputation in the modelling of surfaces of materials.

1. 'Density functional theory studies of the structure and electronic structure of pure and defective low index surfaces of ceria';
2. 'The electronic structure of oxygen vacancy defects at the low index surfaces of ceria'.

We have also published a significant number of papers on modification of titanium dioxide, which is used across many applications, together with experimental collaborators. This has given us a powerful platform to demonstrate our expertise in predicting materials properties.

Examples include controlled modification of TiO2 for pollutant removal or doping of TiO2 to promote stability of the active anatase phase:

 

 

1. 'Molecular-Scale Transition Metal Oxide Nanocluster Surface-Modified Titanium Dioxide as Solar-Activated Environmental Catalysts';
2. 'Surface modification of TiO2 with copper clusters for band gap narrowing';
3. 'Cu-Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity';
4. 'Effect of Cu doping on the anatase-to-rutile phase transition in TiO2 photocatalysts Theory and experiments'.

Finally we have achieved major success in modelling the chemistry of key reactions for renewable energies, including biomethane conversion, C02 conversion and hydrogen conversion:

1. 'In Situ Investigation of Methane Dry Reforming on Metal/Ceria(111) Surfaces: Metal–Support Interactions and C−H Bond Activation at Low Temperature';
2. 'Role of surface reconstruction on Cu/TiO2 nanotubes for CO2 conversion';
3. 'Spinel-Structured ZnCr2O4 with Excess Zn Is the Active ZnO/Cr2O3 Catalyst for High-Temperature Methanol Synthesis';
4. 'Overcoming Pd–TiO2 Deactivation during H2 Production from Photoreforming Using Cu@Pd Nanoparticles Supported on TiO2'.

More recently, we have been highly active in the modelling of the chemistry of atomic level processing, namely atomic layer deposition (ALD), atomic layer etching (ALE) and molecular layer deposition (MLD). These processes are critical for the production of future electronic devices, and are expanding into processing of catalysts and polymer materials. Modelling is a crucial activity for the development of these processes.

In particular, we have some of the first publications on modelling ALE of metals and metal oxides:

1. Mechanism of Thermal Atomic Layer Etch of W Metal Using Sequential Oxidation and Chlorination: A First-Principles Study;
2. In silico design of a thermal atomic layer etch process of cobalt;
3. Self-Limiting Temperature Window for Thermal Atomic Layer Etching of HfO2 and ZrO2 Based on the Atomic-Scale Mechanism.

 

Producing Impact & Real Results

The research in the group is focused around global challenges, particularly in the energy, medical devices and information processing and storage sectors, where each of these is important for achieving the UN sustainable development goals. These are areas where Ireland is already or has strong ambitions to be a world leader and our work provides the fundamental understanding needed to make progress in addressing these challenges.

I was one of the first awardees of the SFI Starting Investigator Research Grant (SIRG) in 2009 and through this award I developed novel materials based on surface modification of TiO₂ with other metal oxides. These new materials systems showed significant potential for enhanced activity of TiO_­2 for water splitting, particularly the water oxidation step (the really difficult step in hydrogen production). A follow-on to this work was supported by the H2020 M-ERA.net co-fund, supported by SFI, where I coordinated the RATOCAT project which lead to the development of new modifications of TiO₂ that promote both the oxidation and reduction chemistries in hydrogen production from water and alcohols. Tight collaboration with experimental groups demonstrated high efficiency materials predicted from our modelling work.

I am coordinating an Enterprise Ireland funded Innovation Partnership with an IDA supported MedTech company which is exploring the design of low friction materials to replace lubricous Teflon currently used in medical devices and novel routes to their deposition that will deliver a number of impacts – reduced use and waste of materials, elimination of Teflon and efficient production of devices. Results to date have demonstrated the ability of modelling to devise materials and predict their deposition chemistry, with validation undertaken at partner facilities. This project showcases the important role of atomistic modelling in product development.

 

Developing Early Career Researchers

Over the past 7 years, I am proud to have graduated six PhD students. Currently I supervise 5 students and 6 postdocs have also worked in the group. Group members have progressed on to senior positions in industry, e.g. pharma and IT or other academic and research positions, including Professorships and Senior Researcher roles. The ability and infectious enthusiasm of the talented people who have worked in our group has been a highlight of mine during my last decade at Tyndall.

I have built an extensive network of experimental and industry collaborators throughout Ireland, Europe and beyond. Many of these are experimental who keep me honest by confronting our results with the reality of experiments and real materials. I have been privileged to coordinate multiple international partnerships, including an SFI US-Ireland project (Ulster University and Northwestern), H2020 M-ERA.net cofund RATOCAT (CSIC Sevilla, TU Delft, PSA-CIEMAT) and an SFI-NSF China Partnership (Fudan) where a close collaboration with experimental collaborators was essential to the success of the project.

I am lucky enough to be recently appointed to the position of Chair of the Science Council of the Irish Centre for High End Computing which oversees the quality of awarded projects and which is taking a more active role in promoting the role and importance of HPC and Scientific Computing in Ireland.