Engineering Ir Atomic Configuration for Switching the Pathway of Formic Acid Electrooxidation Reaction

Switching the formic acid oxidation reaction (FAOR) pathway from CO intermediate to direct CO2 formation is essential for noble‐metal electrocatalysts, but rare investigations on Ir‐based materials. Herein, the atomic configurations of Ir are controlled to enhance the FAOR performance via Ir3V intermetallics (O‐Ir3V). As the ordering degree of O‐Ir3V increases, the Ir ensemble size decreases to trimer and dimer, leading to a 7.3 times promotion in mass normalized activity relative to Ir. Supported by electrochemical in situ attenuated total reflection infrared spectroscopy results, it shows that FAOR occurs via linear CO mediated pathway on Ir, but it is totally switched to a direct pathway on highly ordered O‐Ir3V. The preserved ordered structure and V oxides on the surface during the durability test contribute to the enhanced stability. This study provides an idea to switch the FAOR pathway through tuning the Ir atom configuration by constructing ordered intermetallics. This study presents a strategy to switch the pathway of formic acid electrooxidation reaction via controlling the Ir atomic configurations. The larger Ir ensembles favor the formation of CO intermediates while the smaller Ir ensembles in ordered Ir3V intermetallics promote the direct electrooxidation of formic acid into CO2, which reflects the relationship between CO affinity and Ir atomic configurations.