Exploring the impact of partial pressure and typical compounds on the continuous electroconversion of CO2 into formate

Abstract (English)

Previous research in CO₂ electroreduction primarily focused on cathodic electrocatalysts and electrode configurations using pure CO₂. Few studies explored the impact of residence time and N₂/O₂ compounds, crucial for practical industrial implementation. In this study, the effect of residence time and the influence of N₂ and O₂ compounds on CO₂ electroreduction to formate are investigated, employing Bi carbon-supported nanoparticles in the form of Gas Diffusion Electrodes within an electrochemical flow reactor with a single pass of the reactants. The results highlight the critical role of residence time and the impact of N₂ and O₂ compounds in the CO₂ electroconversion process. On the one hand, the evaluation of residence time holds paramount significance for the potential establishment of a large-scale CO₂ recycling plant, as it has the potential to significantly impact both the capital and operational costs of the integrated electrolyzer-separator system. Optimal results are obtained in the range of residence times between 1.8 and 2.9 seconds, corresponding to CO₂ flow rates of 150 and 250 mL·min⁻¹, respectively. On the other hand, the study resulted in a promising Faradaic Efficiency for formate of 75.0%, with similar values achieved at CO₂ concentrations in the range of 75 – 100 vol%. These results are particularly noteworthy as they demonstrate that achieving a CO₂ capture efficiency of 100% is not necessary, thereby reducing the costs associated with this process and, consequently, the overall cost of integrating both capture and utilization processes in a CO₂ recycling plant.

Notes (English)