Enabling efficient water dissociation in bipolar membranes via collaborative amorphous carbon-TiO2 junction catalyst and anion-exchange layers

Water dissociation (WD) at the junction of bipolar membranes (BPMs) is the core step that governs their energy efficiency in electrodialysis and related electrochemical processes, yet practical design for non-noble WD catalysts and compatible anion-exchange layers (AELs) remain limited. Here, we demonstrate that simultaneously enhancing the electronic conductivity of catalyst and ion-exchange capacity of the AEL effectively accelerates WD kinetics and interfacial ion transport in BPMs. An earth-abundant WD catalyst based on N-doped amorphous carbon/TiO 2 nanoparticles (N-ACNs/TiO 2 ) is designed, where a conductive N-doped carbon framework provides efficient electron transport and nitrogen/oxygen-containing functional groups, while anatase TiO 2 supplies hydroxyl-rich oxide surfaces for interfacial proton-transfer reactions. This junction is integrated with an in situ quaternized composite AEL that offers high water uptake and ion-exchange capacity. Assisted by our designed N-ACNs/TiO 2 catalyst and AEM, the resulting BPM exhibits a low WD voltage (∼1.18 V at 100 mA cm −2 ) and <5% voltage fluctuation at 1000 A m −2 over 6 h in Na 2 SO 4 bipolar membrane electrodialysis. These findings highlight that synergistic optimization of the junction catalyst and AEL architecture provides an effective and scalable interfacial engineering strategy for next-generation BPMs in acid–base electrosynthesis.