Prof DI Dr Anna Regoutz, an Associate Professor in Experimental Inorganic Chemistry at the University of Oxford, Tutorial Fellow in Inorganic Chemistry at St Edmund Hall, and a Visiting Scientist at Diamond Light Source. Anna received her BSc (2009) and Dipl. Ing. (2010) from the Graz University of Technology, Austria, and was awarded a D.Phil. in Inorganic Chemistry from the University of Oxford in 2014. She spent her post-doctoral years at the University of Southampton and Imperial College. She became a Research Fellow at the latter in 2017 and then held a Lectureship in Materials Chemistry at University College London between 2019 and 2024 before joining the University of Oxford in autumn 2024.

Anna leads an interdisciplinary team of experimentalists with key expertise in thin film synthesis, surface and interface chemistry, and X-ray photoelectron spectroscopy. The group’s research vision is to explore the structure-electronic structure relationship in inorganic solids and how this manifests in their overall physico-chemical characteristics to integrate them into opto-electronic devices.

Anna’s awards include the Royal Society of Chemistry’s Joseph Black Award (2020) and the element Praseodymium in IUPAC’s Periodic Table of Chemists (2019). She has been featured in the Merck Next Great Impossible Campaign and the Leading Light series of Diamond Light Source.

Abstract

Chemical bonding and electronic structure of metal dihydrides explored by hard X-ray photoelectron spectroscopy (HAXPES)

Metal hydrides hold significant promise in various hydrogen-related technologies, encompassing energy storage, hydrogen compression, and hydrogen sensing. Although metal hydrides appear simple compared to many other energy materials, understanding the electronic structure and chemical environment of hydrogen within them remains a key challenge. This work presents a new analytical pathway to explore these aspects in technologically relevant systems using Hard X-ray Photoelectron Spectroscopy (HAXPES) on thin films of two prototypical metal dihydrides: YH_2−δ and TiH_2−δ.[1,2] By taking advantage of the tunability of synchrotron radiation, a non-destructive depth profile of the chemical states is obtained using core-level spectra. Combining experimental valence band spectra collected at varying photon energies with theoretical insights from density functional theory (DFT) calculations, a description of the bonding nature and the role of d versus sp contributions to states near the Fermi energy are provided. Moreover, a reliable determination of the enthalpy of formation is proposed by using experimental values of the energy position of metal s band features close to the Fermi energy in the HAXPES valence band spectra.

Selected references

[1] C. Kalha, L. E. Ratcliff, G. Colombi, C. Schlueter, B. Dam, A. Gloskovskii, T.-L. Lee, P. K. Thakur, P. Bhatt, Y. Zhu, J. Osterwalder, F. Offi, G. Panaccione, A. Regoutz, “Revealing the Bonding Nature and Electronic Structure of Early-Transition-Metal Dihydrides”, PRX Energy, 3, 013003, 2024, https://doi.org/10.1103/PRXEnergy.3.013003.

[2] C. Kalha, N. K. Fernando, P. Bhatt, F. O. L. Johansson, A. Lindblad, H. Rensmo, L. Zendejas Medina, R. Lindblad, S. Siol, L. P. H. Jeurgens, C. Cancellieri, K. Rossnagel, K. Medjanik, G. Schönhense, M. Simon, A. X. Gray, S. Nemšák, P. Lömker, C. Schlueter, and A. Regoutz, "Hard X-ray Photoelectron Spectroscopy – A Snapshot of the State-of-the-Art in 2020", J. Phys. Condens. Matter, 33, 233001, 2021, https://doi.org/10.1088/1361-648X/abeacd .