Coupling of pyroelectric effect and salt-induced electric field for enhanced photothermal-assisted photocatalytic hydrogen production.

Abstract

Although photocatalytic hydrogen production offers a clean energy pathway, its application in seawater is limited by low solar-to‑hydrogen efficiency and poor catalyst durability. Here, we describe the development of a floating pyroelectric reactor via electrospinning, which exhibits excellent and stable photocatalytic activity in seawater. Black hollow-shell Mo2C (MC) was integrated with ZnIn2S4 (ZIS) to construct a co-catalytic system, and the resulting composite was incorporated into poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) to prepare PVDF-TrFE/Mo2C@ZnIn2S4 (PTMZ) porous fiber membranes. MC simultaneously improves charge carrier separation in ZIS and acts as a photothermal agent under full-spectrum light. The β-phase in PVDF-TrFE drives heat-induced pyroelectric polarization, collectively boosting photogenerated electron migration of Mo2C@ZnIn2S4 (MC@ZIS). Under 1 sun illumination, floating PTMZ achieves a hydrogen production rate of 4714.0 μmol·m-2·h-1 through the pyroelectric effect, representing a 37.6% increase over that in the submerged state. Moreover, MC@ZIS captures salt ions under illumination to generate an electric field that, coupled with the pyroelectric effect, enables PTMZ to achieve a photocatalytic hydrogen production rate of 5029.5 μmol·m-2·h-1 in artificial seawater, 6.69% higher than in pure water. In addition, PTMZ demonstrates great stability in artificial seawater. These findings provide insights into the development of photocatalysts for seawater applications.

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