Photothermal-regulated photosensitization in hollow ZnCdS photocatalysts for enhanced photocatalytic hydrogen evolution

A photothermal-regulated photosensitization strategy is developed for hydrogen evolution. • Hollow ZnCdS architecture enables photon trapping and localized photothermal conversion. • Fluorescein sensitization provides additional electron-transfer pathways under solar irradiation. • NiS promotes interfacial electron extraction and efficient hydrogen evolution kinetics. • Local thermal fields regulate photosensitized charge transfer for enhanced photocatalysis. The efficient utilization of photogenerated carriers remains a critical challenge for improving hydrogen evolution performance in metal sulfide-based photocatalysts. Herein, we develop a photothermal-photosensitization synergistic strategy by constructing a FL-NiS-ZDS composite photocatalyst through a hard-template approach combined with electrostatic self-assembly. The hollow ZDS architecture enables enhanced photon management through multiple scattering and reflection within the cavity, generating a localized photothermal field with a temperature increase to 41.2 °C under irradiation. This thermal effect accelerates interfacial charge migration and surface reaction kinetics, as evidenced by the reduced apparent activation energy. Meanwhile, fluorescein (FL) acts as a photosensitizer to broaden solar-light utilization up to 600 nm and provides an additional electron-transfer pathway through excited-state electron injection from FL into ZDS. The intimate interfacial coupling among FL, ZDS, and NiS enables efficient charge generation, migration, and utilization, where NiS further promotes hydrogen evolution by facilitating electron extraction and proton reduction. Consequently, the FL-NiS-ZDS photocatalyst achieves a high hydrogen evolution rate of 1807.1 μmol·h −1 under full-spectrum irradiation, together with high apparent quantum yields in the 400–500 nm region and good stability over a 24 h cycling test. This work provides a strategy for integrating localized photothermal regulation with photosensitized charge transfer and offers mechanistic insights into the rational design of efficient solar-driven hydrogen evolution photocatalysts. Download: Download high-res image (142KB) Download: Download full-size image