Exclusive Formation of Formic Acid from CO2 Electroreduction by a Tunable Pd‐Sn Alloy

Conversion of carbon dioxide (CO2) into fuels and chemicals by electroreduction has attracted significant interest, although it suffers from a large overpotential and low selectivity. A Pd‐Sn alloy electrocatalyst was developed for the exclusive conversion of CO2 into formic acid in an aqueous solution. This catalyst showed a nearly perfect faradaic efficiency toward formic acid formation at the very low overpotential of −0.26 V, where both CO formation and hydrogen evolution were completely suppressed. Density functional theory (DFT) calculations suggested that the formation of the key reaction intermediate HCOO* as well as the product formic acid was the most favorable over the Pd‐Sn alloy catalyst surface with an atomic composition of PdSnO2, consistent with experiments. Gut für O: PdSn‐Legierungen auf Trägern wurden als Elektrokatalysatoren der CO2‐Reduktion in wässriger Lösung entwickelt. Über PdSn/C verlief die Ameisensäurebildung bei sehr niedrigem Überpotential (−0.26 V) mit nahezu perfektem Faraday‐Wirkungsgrad. Dieses Resultat wird mit einer optimalen Oberflächenoxid‐Konfiguration erklärt.