Electronic Structure Modulation of Unconventional Phase Metal Nanomaterials for Highly Selective Carbon Dioxide Electroreduction

Abstract

The electrochemical carbon dioxide (CO2) reduction reaction (CO2RR) has been considered as a promising approach to convert atmospheric CO2 to value-added chemicals to promote carbon neutrality. However, developing electrocatalysts with superior activity and high selectivity toward individual products remains a great challenge. Herein we report the electronic structure modulation of unconventional phase metal nanomaterials to achieve highly efficient CO2 electroreduction. It has been found that growing cerium oxide (CeOx) nanostructures on 4H/face-centered cubic (fcc) gold (Au) nanorods can significantly enhance their catalytic activity and selectivity toward the electrochemical conversion of CO2 to carbon monoxide. X-ray analysis indicates the electronic structure change of 4H/fcc Au nanorods after CeOx overgrowth. In-situ attenuated total reflection infrared spectroscopy measurements reveal that the HCO3– concentration near the surface of Au-CeOx heteronanostructures is much higher than that of Au nanorods, facilitating the CO2 reduction process. Density functional theory calculations suggest the activation effect of CeOx on the 4H/fcc Au nanorod surface for the electrocatalytic CO2RR. The synergy between 4H/fcc Au and CeOx promotes the formation of carboxyl (*COOH) species and thus boosts the electrocatalytic CO2RR performance. This work highlights the importance of rational electronic structure regulation of unusual phase nanomaterials toward the electrocatalytic conversion of small molecules.