Advanced bipolar membranes with earth-abundant water dissociation catalysts for durable ampere-level water electrolysis

Green hydrogen production via water electrolysis is a crucial pathway for sustainable energy generation. Bipolar membrane water electrolysis (BPMWE) offers several advantages, including kinetically optimal electrode reactions across pH gradients and reduced component costs. However, challenges such as high overpotential of the BPM for water dissociation (WD) and the need for long-term stability in industrial setting hinder BPMWE development. While various metal oxide catalysts have been explored to reduce WD overpotential in BPMs, the effect of different crystalline phases of interfacial catalysts on BPM performance remains poorly understood. In this study, we investigate the catalytic effects of three titanium dioxide (TiO₂) phases—anatase, rutile, and amorphous—as interfacial catalysts in BPMs. The electrochemical tests reveal that rutile TiO₂, with its uniform dispersion and minimal aggregation, offers excellent WD efficiency. The BPM incorporating rutile TiO₂ achieves current densities of 2300 ​mA ​cm⁻² in pure water electrolysis and 4500 ​mA ​cm⁻² in acid-base electrolysis at 3 ​V and 80 ​°C. Furthermore, in a flow-cell electrolyzer, it sustains stable operation for 200 ​h at 1000 ​mA ​cm⁻². This work addresses critical challenges in BPM development, advancing BPMWE technology and supporting the potential for industrial-scale hydrogen production, thereby willing to contribute to the transition to sustainable energy solutions.