Bifunctional electrocatalysis for CO2 reduction via surface capping-dependent metal-oxide interactions

Multi-component materials are a new trend in catalyst development for electrochemical CO2 reduction. Understanding and managing the chemical interactions within a complex catalyst structure may unlock new or improved reactivity, but is scientifically challenging. We report the first example of capping ligand-dependent metal-oxide interactions in Au/SnO2 structures for electrocatalytic CO2 reduction. Cetyltrimethylammonium bromide capping on the Au nanoparticles enables bifunctional CO2 reduction where CO is produced at more positive potentials and HCOO- at more negative potentials. With citrate capping or no capping, the Au-SnO2 interactions steer the selectivity toward H-2 evolution at all potentials. Using electrochemical CO oxidation as a probe reaction, we further confirm that the metal-oxide interactions are strongly influenced by the capping ligand.