Metal-organic framework thin films for electrocatalysis: A combined ex situ and in situ investigation

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Modern life on the planet is sustained by constant supply of energy, over 80% of which is currently provided by fossil-fuel-based carbon sources (coal, oil and gas). Climate change crisis, combined with dwindling North Sea fuel resources and volatility in the global fossil-fuel market mean there is a pressing need for securement of sustainable energy sources. In this context, electrochemical technologies are becoming increasingly important due to their prominent role in energy conversion, storage, and chemical industries. With renewable electricity being a key strategic component of UK Government's energy policy, coupled with cost reductions of renewable electricity in recent years, electrochemical technologies will play a key role in enabling decarbonisation. Alongside batteries, electrocatalysis is becoming a well-established direction in the domain of energy technologies (e.g., electrolysers and fuel cells) as well as fuels and chemical manufacturing. The applications include: (i) electrochemical conversion of CO2 to produce fuels and chemicals (e.g., formic acid, syngas, ethanol), facilitating carbon capture and utilisation pathways (CCU), (ii) oxidation of low-value waste chemicals (e.g., glycerol from biodiesel industry or ethylene glycol from PET digestion) to generate high-value products used by chemical industries. The primary benefit of such electricity powered processes is their contribution towards reducing the CO2 emission and transitioning to a sustainable society. However, one of the key challenges in making electrocatalytic technologies economically viable is developing inexpensive catalysts that can be used at the electrodes to drive the chemical reactions efficiently. In this context, use of porous materials as a catalyst is appealing because they have large surface area with well-defined pores and channels with integrated catalytic sites. Metal-organic frameworks (MOFs) are such a class of microporous materials with permanent porosity, and their structure can be designed with exceptional degree of control. While these crystalline materials have enormous potential for applications in gas sorption, catalysis, energy storage, light harvesting etc., their use in electrochemical systems has remained problematic due to low conductivity, and thus, many questions remain open in the field.In this proposal, we aim to gain fundamental insight on how these materials operate as electrocatalysts. The overall idea is that the lessons learned from this project will feed into the design principle of next generation of materials. Due to the structural complexity of the MOFs, 'visualising' their structure under operating condition requires a wide range of technical tools including spectroscopy, X-ray diffraction and imaging. For this purpose, we will team up with international researchers to uncover how structural aspects of the materials contribute to the catalytic activity and whether the materials undergo structural reconstruction during catalysis.