Simulation‐based guidance for improving CO2${\rm CO}_{2}$ reduction on silver gas diffusion electrodes

Abstract

The reduction of CO2${\rm CO}_{2}$ in an electrochemical reactor using electrical energy is a promising approach to implement a more sustainable carbon economy and to replace fossil fuels with renewable carbon sources. Conventionally used solid plate electrodes are limited by poor mass transport of the reactants. Gas diffusion electrodes (GDEs) can overcome this limitation and have gained industrial relevance during the last decades. A comprehensive understanding of transport and conversion phenomena within such porous electrodes is not yet well developed. Here, we report a one‐dimensional steady state model of the GDE to investigate the influence of relevant operational parameters and GDE properties on CO2${\rm CO}_{2}$ reduction. The results indicate the importance of controlling the local reaction environment, that is, the reactant concentration and the pH value, by tuning the electrolyte and gas composition, and flow rate as well as the catalyst layer properties.

Application of gas diffusion electrodes in bioeconomy: An update

“…They concluded that the decoupling of the electrochemical and microbial processes into separate reactors overcomes this limitation. Further modeling includes for example, the model‐based improvement of GDE (Heßelmann et al, 2022), model‐based upscaling of GDE based CO 2 ‐reduction systems (Z. Yang et al, 2021) and a multi‐criteria optimization of H 2 O 2 synthesis in GDE (von Kurnatowski & Bortz, 2021).…”

“…They concluded that the decoupling of the electrochemical and microbial processes into separate reactors overcomes this limitation. Further modeling includes for example, the model-based improvement of GDE(Heßelmann et al, 2022), model-based upscaling of GDE based CO 2 -reduction systems (Z Yang et al, 2021). and a multi-criteria optimization of H 2 O 2 synthesis in GDE(von Kurnatowski & Bortz, 2021).6 | CONCLUSION AND OUTLOOKFor improvement of established production processes as well as development of new sustainable and biobased synthesis routes within a circular economy, the combination of biotechnology and electrochemistry is a powerful tool.…”

Micromodel of a Gas Diffusion Electrode Tracks In‐Operando Pore‐Scale Wetting Phenomena

“…[9,10] In the field of GDEs for CO 2 reduction, substantial work has been presented in the literature on catalyst design, [11,12] GDE composition, [13][14][15] and process studies on laboratory scale. [16][17][18] We recently presented a detailed model that predicts speciation and pH gradients for the reduction of CO 2 , [19] and investigated wetting in porous networks comprised of surfaces with different zeta potentials. [20] Although the fundamental Utilizing carbon dioxide (CO 2 ) as a resource for carbon monoxide (CO) production using renewable energy requires electrochemical reactors with gas diffusion electrodes that maintain a stable and highly reactive gas/liquid/solid interface.…”

“…Indirect influences on the fluorescent lifetime might be changes in the local pH value, or the formation of ionic species on the electrodes as is often observed with CO 2 electroreduction. [19,42,43] This reaction visualization via FLIM allows the accurate identification of active areas of the GDE structure.…”

Pilot-Scale CO2 Electrolysis Enables a Semi-empirical Electrolyzer Model

“…Industrial CO 2 electrolyzers will require integration with upstream and downstream chemical processes. − To plan for these deployments, chemical simulations must be able to accurately predict CO 2 electrolyzer behavior at relevant scales. Multiphysics simulations have been used to estimate reaction kinetics, model the pH distribution, improve CO 2 utilization, identify failure mechanisms, and provide a better fundamental understanding of lab-scale reactors. − Most simulations of CO 2 electrolysis are one-dimensional simulations focused on single-carbon products with cell sizes <10 cm 2 (Table S5). Unfortunately, the computational expense of these simulations becomes prohibitive as the reactor grows due to the number of physical parameters and scales involved. , Models have been developed for CO 2 electrolyzers which are useful in predicting specific elements of electrolyzer performance (e.g., cell voltage) but do not produce a complete mass and energy balance .…”