George Tierney

X-ray Absorption Spectroscopy studies of supported nanoparticle catalysts

The generation of high brilliance X-rays at synchrotrons is a uniquely placed tool for studying catalytic systems. One such technique which makes use of the incredibly high photon flux on offer is X-ray absorption spectroscopy (XAS), yielding highly resolved spectra. XAS is a technique based on the photoelectric effect caused by the excitation of ground state electrons toward the continuum of an absorbing species. As the energy required to excite a photoelectron is linked to the absorbing atom XAS is thus an element specific technique.

Importantly, regions of the acquired spectra can be used to determine the average oxidation state and geometry (XANES), as well as the local environment surrounding the absorbing element (EXAFS). Due to the quick acquisition time of data, variations to the chemical state or structure can be measured under in situ or operando conditions, making XAS a very beneficial technique allowing us to monitor the fundamental processes that occur during catalyst synthesis, reaction and deactivation.

Further to this, I am researching the use of bifunctional catalysts in the hydroconversion of hydroconversion of n-alkanes to value added isomeric alkanes. This research continues the work published by Zečević et al, who described changes in the synergistic relationship of metal nanoparticles supported within and on top of zeolite support materials. They reported the effective use of an additional metal oxide component (binder), resulting in the controlled deposition of nanoparticles at closer proximity to the zeolite surface sites, and importantly, optimized catalytic activity and product selectivity. ^[1]

[1]  J. Zečević et al., Nature 528 (2015), 245-248

C.V.

February 2022 – Present

Postdoctoral fellow under the supervision of Prof. dr. Petra de Jongh.

Project: X-ray Absorption Spectroscopy studies of supported nanoparticle catalysts.

February 2017 – June 2021

PhD Degree, University of Southampton, U.K, under the supervision of Dr. Peter P. Wells and co-sponsored by Johnson Matthey.

Thesis: Investigating nanoscale catalysts from primary growth to catalytic activity.

March 2018 & March 2019

Visiting PhD student in the group of Dr. Alberto Villa at Università degli studi di Milano, Milan, Italy, investigating the hydrogenation of furfural over colloidally prepared Pd/TiO₂ catalysts.

August 2018 – September 2018

Electron Microscopy Intern, Johnson Matthey Technology Centre, Sonning Common, U.K.

September 2015 – September 2016

MSc Catalysis, Cardiff University, U.K.

Project: Comparison of preparation method in the oxidative dehydrogenation of propane over mixed metal molybdate catalysts. This project was done under the supervision of Dr. Jonathon Bartley.

September 2012 – June 2015

BSc Chemistry, Cardiff University, U.K.

Project: Development and delivery of scientific outreach workshops and table-top experiments to enrich the perception of chemistry in KS3 students. This project was performed under the supervision of Dr. Dayna Mason.

8 July 1994

Born in Abingdon, United Kingdom.

Links

LinkedIn: https://uk.linkedin.com/in/george-f-tierney-75128b175

ResearchGate: https://www.researchgate.net/profile/George-Tierney

Orcid: https://orcid.org/0000-0002-7409-6362