PhD - Leuven | Just now
With rapidly growing Earth’s energy consumption, alternative energy sources are crucial. Electrochemical CO2 reduction is a very attractive option in this category, as it turns waste into useful chemical fuels, thus closing the carbon cycle and moving towards a carbon-neutral economy. Electrolyzers are the first choice for converting CO2 electrochemically, but the technology is still at a growing stage. At the moment, there are certain drawbacks associated with the different components of the cell, which need improvement to achieve higher energy efficiency of the device and overall long-term performance.
The major drawback with the CO2 electrolyzers is the high cell voltage due to the low solubility of CO2 in aqueous electrolytes. Moving from the liquid phase to the purely vapour phase CO2 electrolysis is an advantageous move. However, a purely vapour phase electrolysis requires certain improvements inside the cell, including high ionic conductivity of the membrane and membrane-electrolyte interface.
Ceramic oxides offer interesting characteristics regarding electronic and ionic conductivity due to their ability to achieve specific phases under different synthesis environments.
Based on the composition, phase, and density of the oxides, the resistivity can be altered as well as the nature of ionic conduction through them. Because of these specific properties, the ceramic oxide materials, MOx, have been used as solid electrolytes for high-temperature fuel cells or similar electrochemical devices. The wide range of electronic and ionic conductivities possible to achieve in MOx systems, especially TiO2, CeO2, and ZrO2 (as well as their M(III) substituted forms), allows us to find the right candidate for the conditions in the cell during the CO2 reduction. Introducing vacancies to an MOx layer or doping it with other atoms can significantly alter its conductivity. Based on this approach, a thin film of MOx, inside the cell can behave as a solid electrolyte, offering high protonic conductivity and ultimately lowering the cell voltage. It can also behave as a selective layer for specific ion transport, which reduces cell voltage further. This makes a meaningful improvement towards the long-term stability of the cell.
Henceforth, the implementation of these ceramic oxide materials, such as TiO2, CeO2, and ZrO2, in low-temperature CO2 electrolysis is a promising and advantageous step towards effective CO2 reduction. It is thus crucial to understand the proton/ion conduction mechanism through the layer to achieve ultimate device performance.
Work description: The candidate will do a systematic literature study on the material properties of ceramic oxides, specifically different phases of MOx. The composition of MOx will be altered by changing the parameters during the deposition process.
Techniques such as ALD or sputter deposition will be used for the preparation of a thin layer of MOx. The deposited material will be characterized by ellipsometry, SEM, elemental analysis, XPS, and Raman spectroscopy. The conductivity of the layer will be screened for different phases with a four-point probe and impedance measurements. Ultimately, electrochemical performance will be directly screened in electrolyzer cells.
Required background: Materials chemistry chemical engineering
Type of work: 80% experimental, 20% literature
Supervisor: Philippe Vereecken
Daily advisor: Debittree Choudhury, Ewelina Wlazlak
The reference code for this position is 2026-185. Mention this reference code on your application form.