Coupling aromatic CH electrooxidation with hydrogen evolution in flow electrolyzer via interface‐engineered electrodes

Abstract The selective electrocatalytic oxidation (ECO) of aromatic CH bonds paired with the hydrogen evolution reaction (HER) offers promising paths to efficient energy use and sustainable organic electrosynthesis. Nevertheless, the intrinsic inertness of CH bonds and the complex electrooxidation pathway remain challenges. Herein, the NiO‐MnO 2 /GF and Pt/MnO/GF with heterointerfaces were fabricated and integrated into a flow electrolyzer for 4‐methylanisole selective electrooxidation to 4‐methoxybenzaldehyde with HER. The anode achieved 1.48 kg m −3 h −1 space–time yield of 4‐methoxybenzaldehyde, while the cathode concurrently produced 9.0 mmol h −1 H 2 . In situ spectroscopy and theoretical calculations demonstrated that Mn 3+ ‐O species promoted the activation of 4‐methylanisole during the electrooxidation process, while the NiO‐MnO 2 heterointerface enhanced 4‐methoxybenzaldehyde desorption and the Pt/MnO interface created electron‐rich Pt δ− sites, thereby accelerating HER kinetics. The ECO‖HER system achieved scalable performance in a three‐layer flow electrolyzer, confirming potential for industrial application. This study demonstrates a platform enabling concurrent fine‐chemical electrosynthesis and clean energy production.