Oxygen-free water electrolysis enabled by direct coupling with ZnO nanoparticle synthesis

초록

Water electrolysis is a promising electrochemical route for producing green hydrogen, which is essential for achieving carbon neutrality. However, conventional systems are limited by high energy demands, primarily due to the sluggish oxygen evolution reaction (OER) that produces low-value oxygen as a byproduct. In this study, we introduce an oxygen-free water electrolysis system that replaces the OER with electrochemical synthesis of ZnO nanoparticles through zinc oxidation. The process operates via two coupled half-reactions: 2H2O + 2e− → H2 + 2OH− and Zn → Zn2+ + 2e−, yielding an overall cell potential of E0 = −0.07 V. At 500 mA cm−2, the system achieves stable operation with energy consumption of only 32.16 kWh kgH2−1, markedly outperforming previous decoupled and alternative oxidation reactions-assisted water electrolysis systems. Additionally, ZnO nanoparticles with 99.8% purity and an average particle size of 350.3 nm were successfully synthesized, resulting in a cost recovery opportunity up to $5,279 kgH2−1

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