The cathodic reduction of carbon dioxide—What can it realistically achieve? A mini review

• The reasons for studying cathodic CO2 reduction are critically reviewed.
• Electrolysis cannot be viewed as a technology for removing CO2 from the atmosphere.
• CO2 reduction is not a likely way to make hydrocarbon fuels.
• Realistic reasons to study the cathodic reduction of CO2 are suggested.

There is a very large literature and continued interest in the electrochemical reduction of carbon dioxide. The reasons for the continued study of this reaction are reviewed. Suggestions that the electrolytic reduction of carbon dioxide can be used to reduce the level of this greenhouse gas in the atmosphere are shown to be wishful thinking. Also, using this reaction as part of a cycle for large-scale energy storage is not a promising technology. More realistic goals are using CO2 as a cheap source of carbon in electrosynthesis and the development of sensors for CO2. The reduction of CO2 is also important from a fundamental viewpoint. Many different products have been confirmed depending on the electrolysis conditions (particularly electrode material and electrolyte medium), and understanding this variation would be a major boost to our understanding of electrode reactions in general. The reduction of CO2 is also an ideal model reaction for developing approaches to increasing the current density for large-scale electrolysis with gaseous reactants.