Operando Studies of Electrocatalysis for Hydrogen Production Using Pioneering Vibrational Spectroscopic Techniques

1. Development of UV Raman (248 nm) instrument for fluorescence free measurements with sample interface.
2. Explore additional process analytical opportunities for Raman applications within bp.
3. Design and construction of in situ cell for Raman microscopy of various electrodes or electrode coating materials during operation for water hydrolysis processes
4. Exploration of catalyst degradation, electrode corrosion and fouling of selected electrocatalytic systems in combination with alternative electron microscopy and mass spectrometry- based characterisation techniques.

This PhD project aims to develop the Raman spectroscopy opportunities with new laser technology at 248 nm. A recent state-of-art example of this (with the same laser) was launched by NASA on the Mars rover for characterisation of Martian rock samples. Optimising the sensitivity of this novel spectrometer with recently available uv optics such as fibre optics, filters (band-pass and notch) as well as the application of multivariate analysis to the spectra will provide a powerful characterisation tool. Several applications of bp interest have already been identified such as the analysis of motor oils and aromatic organics where fluorescence can be a problem. For these applications it will be necessary to develop both static and flow cells for use with the UV Raman system.

The second main aim of the project is the development of Raman microscopy for in operando studies of electrocatalytic cells for hydrogen production in order to develop a more detailed scientific understanding of the processes involved. Many advanced characterisation techniques cannot operate in operando. The development of bespoke characterisation systems to measure during operation is an important advance to understanding the challenges such as catalyst degradation, electrode corrosion and fouling. In operando or in situ studies are a real technical challenge due to the requirements for optical access without disturbing the processes being observed. Our group, with Prof Holmes, have recently demonstrated a proof of concept for the in operando study of direct methanol fuel cell membranes. Raman microscopy (Renishaw InVia system with 785 nm excitation - additionally, funding has been applied from EPSRC for a 532 nm laser) will be used to enable 2D chemical characterisation of the electrode surface in the electrocatalytic reactions. Depth profiling can be also achieved by varying the focus of the excitation laser to below the surface so in principle 3D scans of chemical composition can be made. Other state of the art Raman techniques such as surface enhanced Raman spectroscopy (SERS) will also be explored as part of this work. This can give several orders of magnitude signal increase due to coupling of the excitation beam with metal nano-particles. For this part of the project it will be beneficial to explore similar systems with other advanced characterisation techniques such as XPS, SEM, TEM, SIMS and NMR available at UoM and bpICAM with colleagues.