Unraveling the Effect of Anions (Molybdate and Carbonate) on Reconstruction of Biox Catalysts for Electrocatalytic Co2 to Formate

The catalytic performance of Bi2MoO6 and Bi2O2CO3, synthesized through the ion-exchange of Bi2MoO6 with CO32-, was investigated to discern the influence of anions on the electrochemical CO2 reduction reactions (ECO2RR) activity. The anion effects on the reconstruction were attributed to their influence on Bi-O bonding energy, with the Bi-O bond in Bi-O-C being stronger due to higher electronegativity of carbon than Bi, which enhances electron transfer from Bi to O; conversely, the lower electronegativity of Mo than Bi weakened the Bi-O bond. This thesis is also applicable for predicting the reconstruction of Bi2WO6 and BiOI samples through electrolysis. Bi2O2CO3 demonstrated a formate selectivity of 93.4% at a current density of 36.2 mA cm-2 at -1.0 V versus the reversible hydrogen electrode (RHE), much higher than that of Bi2MoO6. The retention of Bi3+ in Bi2O2CO3 is more catalytically active for *OCHO formation than the metallic Bi produced from Bi2MoO6.