Ag‐Cu Synergistic Effects Promoted Ampere‐Level Halogen‐Mediated Electrosynthesis With Suppressed Oxygen Evolution Reaction

ABSTRACT Halogen‐mediated electrosynthesis is a sustainable strategy for organic synthesis under mild conditions. Yet achieving selective iodoform synthesis at high current remains difficult because of the strong competition between iodide oxidation reaction (IOR) and oxygen evolution reaction (OER). Here, we develop a quinary sulfide catalyst, AgCuCoGeS 4 (ACCGS), synthesized via a thermal injection method, which achieves exceptional IOR selectivity in a flow electrochemical system. Density functional theory (DFT) calculations reveal that the Ag‐Cu synergistic effects in ACCGS widen the adsorption energy gap between I − and *OH intermediates, thereby effectively suppressing the competing OER by weakening *OH binding while strengthening I − chemisorption. Experimentally, ACCGS/GF demonstrates an iodoform yield of 80.3% at 200 mA, marking a substantial enhancement over the 45.0% yield of CoS/GF. It also demonstrates stable operation for 12 h, confirming its excellent long‐term stability. Notably, it sustains a remarkable Faradaic efficiency of 64.1% for IOR at an ampere‐level current of 1000 mA, which highlights its breakthrough in high‐current tolerance. Therefore, this work demonstrates an effective strategy for ampere‐level electrosynthesis by combining multimetallic catalysis with a flow system for halogenated chemical production.