Composition-Dependent Electrocatalytic Behavior of Au–Sn Bimetallic Nanoparticles in Carbon Dioxide Reduction

Bimetallic electrocatalysts offer great flexibility to tailor the activity and selectivity in electrochemical carbon dioxide (CO2) reduction. Here, we report on the electrocatalytic behavior of Au–Sn bimetallic nanoparticles with different intermetallic phases toward CO2 electroreduction. Two high-value products formed with reasonable current density: formic acid in the liquid phase and syngas (CO + H2) in the gas phase. Notably, the phase composition of the catalysts had a massive influence on both activity and product distribution. Selective isotopic labeling studies emphasized the role of bicarbonate as the source of CO and formic acid formation on the AuSn bimetallic phase. In situ Raman spectroelectrochemical studies also demonstrated that the catalytic performance of the AuSn phase was superior to that of its parent metal and other bimetallic counterparts. The achieved control over the product distribution demonstrated the promise of bimetallic nanostructures being employed as efficient catalysts in the electroreduction of CO2.