Decreasing the Energy Consumption of the CO₂ Electrolysis Process Using a Magnetic Field

Abstract

The renewable electricity-powered electrolysis of CO 2 could be a viable carbon-neutral method for producing carbon-based value-added chemicals like carbon monoxide, formic acid, ethylene, and ethanol. A typical CO 2 electrolyzer suffers, however, from the high power requirements, mainly due to the energy-intense anode reaction. In this work, we decrease the anode overpotential and thus reduce the overall cell energy consumption by using a NiFe-based bimetallic catalyst at the anode and applying a magnetic field. For a CO 2 electrolysis process producing CO in a gas diffusion electrode-based flow electrolyzer, we demonstrate that power savings in the range from 7% to 64% can be achieved at CO partial current densities exceeding −300 mA/cm 2 using a NiFe catalyst at the anode and/or by using a magnetic field at the anode. We achieve a maximum CO partial current density of −565 mA/cm 2 at a full cell energy efficiency of 45% with 2 M KOH as the electrolyte.

Design strategies for markedly enhancing energy efficiency in the electrocatalytic CO2 reduction reaction

“…Similarly, through the MHD effect, the OER modulation by applying a magnetic field has successfully lowered the anode overpotentials during the CO 2 RR, resulting in the small cell voltage and higher full-cell EE reaching 45%. 143 Furthermore, strain engineering is another strategy that modulates the activity and selectivity by breaking the scaling relationship. 144,145 As demonstrated by Reske et al, through controlling the thickness of the Cu overlayer on Pt support to adjust the surface tensile strain and adsorption energy of reactive intermediates during the CO 2 RR, the CH 4 and C 2 H 4 selectivity can be controlled.…”

Catalytically Influential Features in Transition Metal Oxides

“…Although an exhaustive explanation for the enhancement remains mysterious, a possible reason on spinel CoFe 2 O 4 may be the expedited reaction kinetics for the first electron transfer step. With rising attention being paid to the usage of applied external magnetic field, more reactions, such as ORR 29 and CO 2 RR, 30 have been found to benefit from the aligned ferromagnetic spin ordering. However, it is worth noting that the external magnetic field also induces some other effects, which may affect the observed activity.…”

Gas Diffusion Electrodes for CO2 and N2 Reduction: A Virtual Issue

“…Another approach to improve performance is to control water transport within the membrane while suppressing the hydrogen evolution reaction. , By promoting alkali cation (K + ) concentrations at the catalyst’s surface, 3-fold increases in CO 2 reduction selectivity have been observed . Other efforts to improve the performance of GDEs include the application of magnetic field and modification of the electrode surface with polymer/enzyme (formate dehydrogenase) layers for electro­enzymatic CO 2 fixation.…”