Boosting Charge-Transfer Efficiency by Simultaneously Tuning Double Effects of Metal Nanocrystal in Z-Scheme Photocatalytic Redox System

Integrating individual functional materials into elegant nanoarchitectures holds great promise for creating high-efficiency photosynthesis systems with unique structure directing merits. Herein, an all-solid-state metal-based Z-scheme photocatalytic system consisting of well-defined one-dimensional WO3@Au@CdS core shell heterostructure has been progressively and rationally designed by a green and facile two-step wet-chemistry approach. Significantly, it was uncovered that Au ingredient sandwiched in between the interfacial domain of WO3 and CdS layer plays simultaneous dual roles in boosting the visible-light-driven photoactivities of core-shell ternary heterostructure, that is, as interfacial charge-transfer mediator to expedite vectorial Z-scheme electron transfer between CdS and WO3 and plasmonic photosensitizer to trigger the generation of plasmon-induced hot electrons, thereby substantially augmenting the photoelectron density in a photoredox catalytic system. Such cooperative concurrent dual roles of Au nanocrystal in Z-scheme photocatalytic system results in the versatile and considerably enhanced photoredox performances of plasmonic WO3@Au@CdS core-shell heterostructure toward anaerobic reduction of aromatic nitro compounds to corresponding amines and mineralization of organic pollutants under visible light irradiation at ambient conditions. Moreover, predominant active species during the photoredox catalysis were accurately determined, on the basis of which the photocatalytic mechanism was reasonably deduced and clearly elucidated. This work would provide a quintessential paradigm to uncover the essential roles of metal nanocrystals along with their cooperative synergy in Z-scheme photocatalytic system for substantial solar energy conversion.