Carbon capture, utilization, and storage (CCUS) strategies are gaining attention as effective methods to achieve carbon dioxide neutrality while creating value-added products through CO₂ conversion. Among these strategies, electrochemical CO₂ reduction stands out due to its low temperature and pressure requirements and its ability to store energy from renewable sources like solar and wind in the form of valuable chemicals such as formic acid or formate [1].

The “Development of Chemical Processes and Pollution Control” (DePRO) research group at the University of Cantabria, Spain, has been actively working on the continuous electrochemical reduction of CO₂ to formate. Various electrocatalysts for both the cathode and anode, along with different electrode configurations, have been investigated. This communication focuses on the recent advancements and challenges in the lab’s research on continuous CO₂ electrocatalytic reduction to formate. The experiments were conducted using a consistent setup and operating conditions, with variations in cathodic electrocatalysts, including Pb-, Sn-, and Bi-based materials, and different cathode configurations like plate electrodes, particulate electrodes (PE), Gas Diffusion Electrodes (GDE), Catalyst Coated Membrane Electrodes (CCME), and Membrane Electrode Assembly (MEA). We have also explored various anodes, such as DSA/O₂ and Ni-based electrodes, and different ion exchange membranes, including Nafion cationic exchange membranes (CEM) and Sustainion anionic exchange membranes (AEM), while performing the Oxygen Evolution Reaction in the anodic compartment [2].

Notable achievements were made using a Bi MEA configuration with a CO₂-humidified input stream [3]. These results include formate concentrations of up to 337 g·L^-1, Faradaic Efficiencies of 89 %, and energy consumption values as low as 180 kWh·kmol^-1, representing one of the best trade-offs reported in the literature, marking noteworthy progress in this field.

Further research is essential to scale up this process industrially by developing more stable electrocatalysts for both the cathode and anode. Recent work by the research group has focused on optimizing the manufacturing of GDEs for CO₂ electroreduction to formate using the automatic spray pyrolysis technique [4]. This approach has yielded valuable insights into creating more efficient electrodes for CO₂ reduction.

Additionally, replacing the Oxygen Evolution Reaction at the anode with more valuable oxidation reactions is crucial. The research group has explored the coupling of the Glycerol Oxidation Reaction with CO₂ electroreduction to formate, resulting in valuable products in both compartments of the electrochemical reactor. Recent results include high formate concentrations of up to 359 g·L⁻¹ with Faradaic efficiencies up to 95% at the cathode, along with dihydroxyacetone production at a rate of 0.434 mmol·m⁻²·s⁻¹ [5]. This represents a significant advancement in the development and application of this technology.