A Cu20 Cluster-Based Moisture-Absorbent Composite Membrane for Efficient Photocatalytic Hydrogen Evolution in Seawater under Non-Contact Configuration

Abstract

Photocatalytic hydrogen production (PHE) from seawater is a critical pathway for overcoming resource constraints.However, salt ions present in seawater can significantly inhibit the photocatalytic hydrogen evolution activity and shorten the cyclic service life of photocatalysts. In this study, a copper-cluster-based moisture-absorbing composite membrane (Cu20/FL/PVA) was designed and fabricated using polyvinyl alcohol (PVA) as the matrix and fluorescein (FL) as the photosensitizer. The composite membrane exhibits excellent moisture absorption properties and can drive the hydrogen evolution reaction under non-contact liquid water conditions. Based on this property, the composite membrane is suitable for the PHE using seawater vapor, significantly inhibiting the poisoning effect of salt components in seawater on the photocatalyst. Compared with the FL/PVA membrane, Cu20/FL/PVA composite membrane with a 10% copper cluster loading exhibits a 3-fold enhancement in hydrogen production rate, reaching 1.46 mmol/m 2 within 4 hours. Furthermore, the composite membrane achieved stable hydrogen production in seawater for 8 h, with a final hydrogen production rate of 1.65 mmol/m 2 . After photocatalysis, confirmed that the composite membrane maintained excellent structural stability during the photocatalytic process. This research provides significant theoretical and practical significance for promoting the sustainable development of photocatalytic seawater hydrogen production technology.