A BiPb bimetallic electrode for highly selective CO2 conversion to formate

• BiPb bimetallic electrode with mixed phases was prepared for CO 2 RR. • The BiPb generates high selectivity and activity for CO 2 RR toward formate. • The BiPb has higher formate ECSA-normalized partial current densities than single Bi and Pb. • The crystalline phase of BiPb would transform from metal Bi and Pb 7 Bi 3 into Bi 2 O 2 CO 3 . Electrochemical CO 2 reduction technology can chemically transfer carbon dioxide into high value-added chemicals and fuels by utilizing renewable energy. However, it still needs more exploration of electrocatalysts with high activity, superior selectivity, and excellent durability in converting CO 2 to storable carbon-based liquid fuels. Herein, we develop a BiPb bimetallic electrode with metal Bi and alloy Pb 7 Bi 3 crystalline phase by a pulse-electrodeposition method with multiple cycles. The prepared BiPb electrode can generate a high catalytic selectivity and activity for the electroreduction CO 2 to formate with good current density (15.56 mA cm -2 ) at -0.96 V vs. RHE and desired long-term durability. The BiPb has higher formate ECSA-normalized partial current densities than single Bi and Pb at the whole potential range, suggesting that it possesses higher intrinsic activity and selectivity toward formate production. Furthermore, during the long-term test, the crystalline phase of the BiPb electrode would transform from metal Bi and Pb 7 Bi 3 into Bi 2 O 2 CO 3 because the BiPb is exposed in CO 2 -rich 0.5 M KHCO 3 electrolyte at -0.96 V vs. RHE. This work may arouse worthy interests in mixed crystals of the bimetallic electrode to achieve efficient electrocatalysts for selective CO 2 conversion toward the generation of valuable carbon-based chemicals.