Electrochemical CO2 conversion with a flow-through copper hollow fibre: A process parameter evaluation

Incentive for the development of techniques that utilize CO2 as a feedstock, is provided by emission of fossil-derived carbon dioxide (CO2) and its corresponding accumulation in the atmosphere. The dissertation focusses on a method to convert CO2 in carbon monoxide (CO), while utilizing renewable electricity to drive the reaction. Contrary to the commonly used flat-sheet electrodes where CO2 is flown past the electrode, the research presented in the dissertation utilizes a tubular, copper gas diffusion electrode, with CO2 flown through the porous wall of the electrode. The dissertation studies the behaviour of these so-called copper hollow fibre electrodes operated in flow-through configuration in different reaction conditions. The outline of the dissertation is as follows. Chapter 1 puts the work presented in this dissertation in a wider perspective, and introduces the main reactions and parameters involved in electrochemical CO2 conversion. The subsequent chapter, Chapter 2, investigates the consequences of feeding a mixture of CO and CO2 to copper hollow fibre electrodes, while aiming for electrochemical CO2 conversion. Chapter 3 studies the effect of the aqueous electrolyte identity on the performance of copper hollow fibre electrodes. The following chapter, Chapter 4, investigates the fibre’s ability to convert CO2 in ethylene rather than CO. The final chapter of the dissertation, Chapter 5, reflects upon the research presented in the dissertation. The dissertation concludes that if the copper hollow fibres are to be used as CO2 to CO electrocatalyst, the fibre’s surface characteristics and its operating conditions are to be changed such that H2 and formate production are limited, while CO production is allowed to occur

Optimizing temperature treatment of copper hollow fibers for the electrochemical reduction of co2 to co

Copper hollow fibers were prepared via dry-wet spinning of a polymer solution of N-methylpyrrolidone, Polyetherimide, Polyvinyl Pyrolidone, and copper particles of sizes in the range of 1–2 µm. To remove template molecules and to sinter the copper particles, the time of calcination was varied in a range of 1–4 h at 600◦C. This calcination temperature was determined based on Thermal Gravimetric Analysis (TGA), showing completion of hydrocarbon removal at this temperature. Furthermore, the temperature of the subsequent treatment of the fibers in a flow of 4% H2 (in Ar) was varied in the range of 200◦C to 400◦C, at a fixed time of 1 h. Temperature programmed reduction experiments (TPR) were used to analyze the hydrogen treatment. The Faradaic Efficiency (FE) towards CO in electrochemical reduction of CO2 was determined at −0.45 V vs. RHE (Reversible Hydrogen Electrode), using a 0.3 M KHCO3 electrolyte. A calcination time of 3 h at 600◦C and a hydrogen treatment temperature of 280◦C were found to induce the highest FE to CO of 73% at these constant electrochemical conditions. Optimizing oxidation properties is discussed to likely affect porosity, favoring the CO2 gas distribution over the length of the fiber, and hence the CO2 reduction efficiency. Treatment in H2 in the range of 250 to 300◦C is proposed to affect the content of residual (subsurface) oxygen in Cu, which leads to favorable properties on the nanoscale

Data underlying the PhD dissertation 'Electrochemical CO2 conversion with a flow-through copper hollow fibre - A process parameter evaluation'

Data underlying the PhD dissertation 'Electrochemical CO2 conversion with a flow-through copper hollow fibre - A process parameter evaluation'The dataset contains three zip-files:The electrolyte data.zip involves the study of the effect of the electrolyte identity (NaHCO3, KHCO3, CsHCO3, K2SO4, and KH2PO4 in water) on the performance of a copper hollow fibre electrode acting as CO2 conversion electrocatalyst, discussed in Chapter 3 of the dissertation.Data chapter 4.zip involves the study of the ability of copper hollow fibre electrodes to convert CO2 in ethylene, discussed in Chapter 4 of the disseration.Data Table 5.1.zip provides the data underlying Table 5.1 of the dissertation.</p

Data underlying the PhD dissertation 'Electrochemical CO2 conversion with a flow-through copper hollow fibre - A process parameter evaluation'

Data underlying the PhD dissertation 'Electrochemical CO2 conversion with a flow-through copper hollow fibre - A process parameter evaluation'The dataset contains three zip-files:The electrolyte data.zip involves the study of the effect of the electrolyte identity (NaHCO3, KHCO3, CsHCO3, K2SO4, and KH2PO4 in water) on the performance of a copper hollow fibre electrode acting as CO2 conversion electrocatalyst, discussed in Chapter 3 of the dissertation.Data chapter 4.zip involves the study of the ability of copper hollow fibre electrodes to convert CO2 in ethylene, discussed in Chapter 4 of the disseration.Data Table 5.1.zip provides the data underlying Table 5.1 of the dissertation.</p