Investigation of electrochemical carbon dioxide reduction properties of gold-copper oxide tandem catalyst

Abstract

In order to solve the problem of global warming caused by excessive emission of carbon dioxide, a technology for converting carbon dioxide into other compounds by an electrochemical method is being studied worldwide. Electrochemical carbon dioxide reduction is an eco-friendly technology that reduces carbon emissions while converting carbon dioxide into high value-added compounds. Copper oxide is known as a catalyst material showing high selectivity for multi-carbon compounds among carbon dioxide reduction catalysts. By utilizing tandem catalyst to create a dense environment with a carbon monoxide intermediate and carbon monoxide (CO) around the copper oxide catalyst, a multi-carbon compound with high selectivity can be produced at a lower overpotential. However, although many studies of enhanced performance of the tandem catalyst have been reported, the size and density of the CO generating catalyst have not well understood. In this study, the carbon dioxide reduction properties were evaluated by controlling the size and density of gold nanoparticles as CO generating catalyst and the correlation was identified. The more 5 nm-sized gold nanoparticles were distributed, the more the Faraday efficiencies of multi-carbon compounds were shown at a low overpotential of ~ 80 mV at the high current density region. In particular, the selectivity of 1-propanol was doubled at the same voltage as that of the copper oxide catalyst. When the size of the gold nanoparticles increased, there was no significant difference from the characteristics of the existing copper oxide catalyst, and the applied density did not affect it. This research presents a study on the characteristics of auxiliary catalysts for tandem catalysts to increase the performance of electrochemical carbon dioxide reduction catalysts.