The Challenge of Carbon Dioxide Reduction

The current density of 100-1000mAcm-2 is more suitable for CO2 electroreduction reaction. However, the low solubility of CO2 in the aqueous environment limits the reaction current density of many laboratory scales to only 1-10mAcm-2. The solvent in the water phase is also prone to hydrogen generation, thereby sharing the source of protons for reducing carbon dioxide. Lowering the pH is conducive to the production of hydrogen, and increasing the reaction temperature can reduce the solubility of carbon dioxide. Therefore, many carbon dioxide electrolytic cells operate at room temperature and standard atmospheric pressure and use alkaline electrolyte. Some CO2 electric reduction systems use high pressure to increase the solubility of CO2, and the high pressure environment is not good for hydrogen.

In the next 10 to 20 years, more realistic commercialization can only be achieved in smaller markets that do not exclude new technologies, especially in markets that do not compete with traditional chemical products. CO2 electroreduction technology is generally regarded as a technology for manufacturing liquid fuels, and the market for liquid fuels is a difficult market to enter. Therefore, the commercialization of CO2 electroreduction technology should be concentrated in some market areas where its characteristics can be used. The CO2 electric reduction technology can quickly obtain high current density, which plays an important role in buffering the fluctuation of renewable energy and ensuring the stability of the grid frequency. Its high selectivity makes its products contain less impurities and can be used as raw materials for the next reaction.

Although the high reactive overvoltage may become an obstacle in the future, improving the bias voltage cannot directly solve the pain points of the current energy market. Through electro-reduction technology, the stable and highly selective production of carbon monoxide and formic acid can obtain higher production value and can even compete with existing products. Designing electrolytic cells and catalysts on this basis can help us solve many obstacles in the carbon dioxide electroreduction technology and understand how to control stability and selectivity.