Bimetallic plasmonic thermo-cycling driven by strong interfacial coupling in dual-hollow structure for enhanced photothermal hydrogen production.

Conventional photocatalysts exhibit various limitations, including the insufficient utilization of near-infrared (NIR) light and the rapid recombination of photogenerated carriers. To address these limitations, a novel double-hollow plasmonic nanoreactor (H-ZISv/Au-Ag) with a "Plasmonic Thermo-Cycling (PTC)" enhancement mechanism was prepared herein. The cocatalyst, Au-Ag hollow alloy particles (HAPs), was embedded within the hollow structure via sulfur vacancy-mediated strong interfacial coupling, which synergistically enhances light scattering/reflection and promotes directional charge transfer. Subsequently, the localized surface plasmon resonance (LSPR) of Au-Ag HAPs extends light absorption into the NIR region and generates an intensely enhanced local electromagnetic field, enabling efficient hot electron excitation and remarkable photothermal conversion. Notably, the optimized Schottky junction, plasmonic near-field enhancement, and dual-cavity confinement effect synergistically improve the performance of the photothermally assisted photocatalytic hydrogen evolution (PTHE) reaction. Under AM 1.5G illumination at without cooling water (WCW), the catalyst achieved a high hydrogen evolution rate of 18.08 mmol·g-1·h-1, which is 2.99 times greater than that of pristine H-ZISv. The catalyst also demonstrates excellent stability over 750 min and exhibits measurable NIR-driven activity at 800 nm. In summary, this work establishes an effective strategy for achieving highly efficient photothermal hydrogen production by integrating defect engineering, a double-hollow nanostructure, and bimetallic plasmon resonance.