Recent Progress in CO2 Reduction using Bimetallic Electrodes Containing Copper

• Cu bimetallics are amongst the most promising materials for CO 2 electro-reduction. • These materials often give products more deeply reduced than CO/formate. • Products with C–C bonds can also be obtained. • Progress in the development of these materials from the last two years is reviewed. • The review focuses on systems producing species more reduced than CO/formate. Rising levels of carbon dioxide in the atmosphere have precipitated considerable research efforts aimed at generating energy from renewable sources, such that consuming this energy does not lead to further increases in atmospheric CO 2 . Simultaneously, atmospheric CO 2 represents a useful feedstock for the storage of renewably-generated energy, in particular through electroreduction of CO 2 powered by renewables to give hydrocarbon fuels that when burned do not increase net CO 2 levels in the atmosphere. In order to bring such renewable-powered production of hydrocarbons from CO 2 to reality, improved electrocatalysts for carbon dioxide reduction are required. For example, Cu is the only single metal that demonstrates appreciable Faradaic efficiency for CO 2 reduction products that are reduced by more than two-electrons, but pure Cu is not an especially active or selective catalyst for this process. Hence there has been considerable interest in making bimetallic catalysts using Cu in combination with other metals in order to find systems that can reduce CO 2 to products such as methane, methanol, ethanol and beyond. In this minireview, we give an overview of recent progress in CO 2 electroreduction using bimetallic cathodes composed of copper and various other metals in combination, with a particular focus on studies going beyond two-electron reduction products from the last two years.