Advances in electrolyzer design and development for electrochemical CO₂ reduction

Abstract

In view of global energy transition and environmental issues, electrochemical conversion of carbon dioxide (CO 2 ) to high value-added chemicals by using clean renewable electricity, as an advanced carbon capture, utilization and storage (CCUS) technology, demonstrates a promising approach to reach the carbon neutrality with additional economic benefits as well. Over the past decade, various new valid catalysts in electrochemical CO 2 reduction (ECO2R) have been designed and intensively investigated. Unfortunately, constructing appropriate ECO2R electrolyzer with high conversion rate and long-term stability to unleash the full potential benefits of electrocatalysts remains a recognized challenge, especially as it has not yet attracted attention. This review summarizes the progress of ECO2R reactor and their corresponding structure characteristics/ electrochemical performance. Besides, the current challenges and bottlenecks of CO2RR reactor are discussed. We aim to introduce the advances in ECO2R electrolyzer in detail to offer enlightenment for large-scale industrial application of ECO2R.

Water electrolysis for hydrogen production: from hybrid systems to self-powered/catalyzed devices

“…MEAs typically consist of a five-layer structure, wherein a catalyst-coated membrane (CCM) is sandwiched between two gas diffusion layers (GDLs) or an ion-exchange membrane is placed between two gas diffusion electrodes (GDEs). 152,153 Notably, the continuous circulation of the electrolyte over the electrode surface in MEAs helps overcome the mass-transport limitations encountered in conventional H-type cells or single cells. 154–156 Furthermore, the zero-gap configuration achieved by pressing the GDL, catalyst layer, and ion-exchange membrane together in an MEA greatly reduces system impedance, thereby improving the reaction rate and overall energy efficiency.…”

Perspectives of Magnetically Enhanced Electroconversion of CO2 to Formic Acid and Formate

“…So far, several electrochemical reactors have been used for the conversion of CO 2 to formic acid/formate. The most relevant types of cells include H-type, two-compartment electrochemical reactors, three-compartment electrochemical reactors and undivided reactors. , The H-type reactor consists of an H-form cell that comprises the anodic and cathodic compartments separated by an ion exchange membrane that promotes the selective mass transport. ,, H-type reactors offer a simple operation to experimentally analyze the performance of new electrocatalysts working in batch mode. However, the improvement of mass transport limitations and the scale-up of the process require operation in continuous mode .…”

“…However, the improvement of mass transport limitations and the scale-up of the process require operation in continuous mode . In this regard, the continuous ERCO 2 is typically performed in the last three reactors previously introduced. ,, In the two-compartment electrochemical reactor, the compartments are separated by an ion-exchange membrane (cationic, anionic, or bipolar). Additionally, in three-compartment electrochemical reactors a central compartment is separated from the anodic and cathodic compartments by cationic and anionic exchange membranes, respectively. ,, Compared to these electrochemical reactors, undivided reactors, which include compartmentless filter press and microfluidic reactors, do not involve separators between compartments, and thus the anode and cathode are in the same compartment. ,, The absence of separators is advantageous, regarding the avoidance of the dependence on the stability of the separator.…”

“…However, it has associated a loss of both activity and material. , The gas diffusion electrode (GDE) represents the most promising and advanced cathode configuration for the conversion of CO 2 to formic acid/formate. GDEs comprise a catalytic layer (CL) and a gas-diffusion layer (GDL); the CL, where the ERCO 2 takes place, consists of catalyst particles and an ionomer. ,, …”

Efficient electrochemical upgradation strategies for the biomass derivative furfural

“…Compared with the classical H-type reactors, flow reactors not only provide a more uniform electric field distribution, but also enhance the contact between reactants and electrodes, which are conducive to promoting mass transfer and improving electrolytic efficiency. 75,76 In divided flow reactors, adjusting only the flow rate can achieve >85% FAL selectivity and 100% FF conversion. 77 Flow reactors can not only realize continuous electrolysis, but also facilely expand the production scale by increasing the number of electrolytic units.…”