PDRA in the Walton group developing retrofittable cells to conduct near ambient pressure XPS in conventional XPS instruments.
My PhD research focused on operando characterisation of nanocatalysts for water electrolysis using NAP-XPS. This research developed a new working electrode assembly in with a half CCM geometry. This working electrode assembly was utilised to investigate the structure-activity of iridium oxides under OER conditions and develop a potential programmed NEXAFS technique. This research was supported by Johnson Matthey and Diamond Light Source.
During my undergraduate studies I gained industrial experience working on thin film solid state battery R&D.
My work focusses on sample environment development and for XPS.
A Catalyst-Coated Mesoporous Carbon–Membrane Electrode Assembly for In Situ Soft X-ray XPS and NEXAFS Studies of Electrocatalytic Interfaces James J. C. Counter, Santosh Kumar, Christopher M. Zalitis, Mark Clapp, Alexander. I. Large, David C. Grinter, Matthijs A. van Spronsen, Pilar Ferrer, Burcu Karagoz, Tugce Eralp Erden, Roger A. Bennett, Georg Held ACS Electrochemistry, 2026 High Resolution Image Download MS PowerPoint Slide In situ soft X-ray spectroscopy provides direct insight into the electronic structure of electrocatalysts under realistic reaction conditions but remains technically challenging due to the need to combine aqueous electrochemistry with ultra-high-vacuum detection. Here, we present a mesoporous carbon–membrane working electrode assembly (WEA) that enables window-free in situ XPS and NEXAFS measurements during electrochemical reactions. The design integrates a Nafion proton-exchange membrane with a mesoporous carbon–ionomer contact layer and a thin IrO x catalyst layer, providing continuous electronic and protonic pathways and stable hydration through the membrane. By tuning the chamber water vapor pressure to 8 mbar, the WEA maintains a nanometer-thin water layer sufficient for the oxygen evolution reaction (OER) while preserving photoelectron detection efficiency. A robust peristaltic pump integrated with an alumina-bed water vapor dosing system maintains steady-state hydration at 6–10 mbar with <±0.1 mbar variation, enabling reproducible in situ spectra over extended periods. In situ Ir 4f and O 1s XPS reveal oxidation of Ir 3+ /Ir 4+ to Ir 4+ /Ir 5+ and dynamic changes in hydroxyl and lattice oxygen species, while O K-edge NEXAFS identify the formation of potential-stabilized μ 2 –O and μ 1 –O oxygen ligand species at OER. The WEA thus provides a quantitative, window-free platform for probing electrochemical interfaces under near-ambient conditions and establishes a general methodology for in situ soft X-ray studies of functional electrocatalysts, closely resembling the architecture and operation of industrial membrane-based water electrolyzers. This approach establishes a reliable methodology for coupling electrochemistry with the element specific soft X-ray spectroscopy under realistic reaction conditions.
Operando XPS studies of precisely size-selected Pd nano-catalysts for methane oxidation Alexander I. Large, Henry Hoddinott, Haamidah Sana, Elizabeth Jones, James J. C. Counter, Matthijs A. van Spronsen, Santosh Kumar, David C. Grinter, Pilar Ferrer, Bernd von Issendorf, Richard E. Palmer, Georg Held Faraday Discussions, 2026 Changes in the chemical composition of size-selected Pd nanoparticles were studied by near-ambient pressure XPS under dry and wet reaction conditions for methane oxidation (CH 4 + O 2 [+H 2 O]) in the temperature range between 150 °C and 450 °C.
An electrochemical flow cell for operando XPS and NEXAFS investigation of solid-liquid interfaces Santosh Kumar, James J C Counter, David C Grinter, Matthijs A Van Spronsen, Pilar Ferrer, Alex Large, Marcin W Orzech, Pawel Jerzy Wojcik, Georg Held Jphys Energy, 2024 Suitable reaction cells are critical for operando near ambient pressure (NAP) soft x-ray photoelectron spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS) studies. They enable tracking the chemical state and structural properties of catalytically active materials under realistic reaction conditions, and thus allow a better understanding of charge transfer at the liquid–solid interface, activation of reactant molecules, and surface intermediate species. In order to facilitate such studies, we have developed a top-side illuminated operando spectro-electrochemical flow cell for synchrotron-based NAP-XPS/-NEXAFS studies. Our modular design uses a non-metal (PEEK) body, and replaceable membranes which can be either of x-ray transparent silicon nitride (SiN x ) or of water permeable polymer membrane materials (e.g. NafionTM). The design allows rapid sample exchange and simultaneous measurements of total electron yield, Auger electron yield and fluorescence-yield. The developed system is highly modular and can be used in the laboratory or directly at the beamline for operando XPS/ x-ray absorption spectroscopy investigations of surfaces and interfaces. We present examples to demonstrate the capabilities of the flow cell. These include an operando NEXAFS study of the Cu-redox chemistry using a SiN x /Ti-Au/Cu working electrode assembly (WEA) and a NAP-XPS/-NEXAFS study of water adsorption on a NafionTM polymer membrane based WEA (NafionTM/C/IrO x catalyst). More importantly, the spectro-electrochemical flow cell is available for user community of B07 beamlines at Diamond Light Source.
In situ methods: discoveries and challenges: general discussion Rosa Arrigo, Damien Aureau, Prajna Bhatt, Mark A. Buckingham, James J. C. Counter, Giulio D’Acunto, Philip R. Davies, D. Andrew Evans, Wendy R. Flavell, Joshua S. Gibson, Shaoliang Guan, Georg Held, Mark Isaacs, J. Matthias Kahk, Claus F. P. Kastorp, Heath Kersell, Alenka Krizan, Alexander I. Large, Robert Lindsay, Johannes Lischner, Patrick Lömker, David Morgan, Slavomír Nemšák, Anders Nilsson, David Payne, Benjamen P. Reed, Olivier Renault, Günther Rupprechter, Alexander G. Shard, Mzamo Shozi, Mathieu G. Silly, William S. J. Skinner, Francine Solal, Kelsey A. Stoerzinger, Sefik Suzer, Juan Jesús Velasco Vélez, Marc Walker, Robert S. Weatherup Faraday Discussions, 2022 Sefik Suzer opened discussion of the introductory lecture by Wendy Flavell: What are your thoughts about cryo-XPS? Is environmental XPS similar to cryo-XPS? A lot of biologists ask when cryo-XPS will be widely available. In your opinion, when do you think that the instrument makers will conside
Time resolved surface analysis (kinetic and molecular time scales): general discussion Rosa Arrigo, Damien Aureau, Loren Ban, Thorsten Bartels-Rausch, James J. C. Counter, Philip R. Davies, Martina Dell’Angela, Michael Dowhyj, Andrew Evans, Wendy Flavell, Georg Held, Claus F. P. Kastorp, Robert Lindsay, Anders Nilsson, Evgeniy Redekop, Olivier Renault, Günther Rupprechter, Mathieu G. Silly, Sefik Suzer Faraday Discussions, 2022 Wendy Flavell opened a general discussion of the paper by Martina Dell’Angela: You have very nicely separated out two separate timescales for the dynamics in this system. In the context of the SPV, clearly this scales with fluence, but (quite apart from the ‘n/p’ issue) naively I wondered if yo
INDUSTRY EXPERIENCE
1 year in industry with Ilika PLC conducting characterisation and tear-down of Stereax thin film solid state batteries. During my placement I ran a research project investigating the diffusion co-efficient of the materials used.
