Local Acidic Microenvironments Enhanced Anodic Formamide Electrosynthesis over Isolated Pd Sites

Abstract

Abstract Electrocatalytic C─N oxidative coupling of methanol and ammonia enables sustainable formamide synthesis under ambient conditions. However, the poor C─N coupling selectivity and limited Faradaic efficiency hinder practical application. As the critical step involves nucleophilic attack of NH 3 on in situ generated *CH 2 O intermediates, enhancing *CH 2 O electrophilicity while suppressing over‐oxidation is essential. Herein, Pd single atoms anchored on MnO 2 nanoarrays achieve state‐of‐the‐art Faradaic efficiency (62.6%) and carbon selectivity (80.2%) for anodic formamide synthesis. In situ characterization and theoretical simulations reveal dual enhancement mechanisms: Isolated Pd sites adopt end‐on *CH 2 O adsorption to expose the electrophilic carbon, while the MnO 2 ‐induced acidic microenvironment enhances *CH 2 O electrophilicity via oxygen‐atom protonation. This synergy accelerates nucleophilic attack by NH 3 , enabling efficient C─N coupling.