Getting the Most of Your Catalyst: How Process Parameters and Pulse Procedures Affect the Performance of eCO 2 R

ChemElectroChem, vol. 13

Abstract

Electrochemical pathways that convert CO 2 into multi‐carbon (C 2+ ) products could mitigate greenhouse gas emissions while supplying chemical building blocks. Realizing this potential requires scalable process designs and optimized operating strategies, including dynamic modes such as pulsed current. Here, we systematically investigate the effects of current density, electrolyte temperature, CO 2 excess rate, and pulsed operation on C 2+ production in a commercially available flow cell equipped with gas diffusion electrodes (GDEs) and industrially relevant materials. High current densities up to 400 mA cm −2 significantly increased the Faradaic efficiency toward C 2+ products. Lower electrolyte temperature (20 °C) enhanced C 2+ production compared to 40 °C, likely due to greater CO 2 solubility and CO adsorption, which promote CO dimerization. A reduced CO 2 excess rate ( λ = 2) further favored C 2+ formation, potentially by decreasing CO 2 adsorption in favor of CO surface coverage. Contrary to prior reports in H‐type cells, pulsed current operation did not improve C 2+ production in the GDE‐equipped flow cell, suggesting that enhanced mass transport minimizes pulsing benefits observed in diffusion‐limited systems. This study identifies low temperature, reduced CO 2 excess, and statically applied high current densities as key parameters for enhancing C 2+ formation under scalable conditions.

Authors 4

1. Florian Pradellok Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering RWTH Aachen University Aachen Germany

2. Jan Hüwels Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering RWTH Aachen University Aachen Germany

3. Matthias Weßling Aachen Chemical Process Engineering DWI – Leibniz Institute for Interactive Materials Aachen Germany

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering RWTH Aachen University Aachen Germany

   DWI ‐ Leibniz Institute for Interactive Materials Aachen Germany

4. Robert Keller corresponding Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering RWTH Aachen University Aachen Germany