Selective organic transformation over a self-assembled all-solid-state Z-scheme core–shell photoredox system

Abstract

Z-Scheme artificial photosystems, resembling the natural photosynthesis procedure, circumvent the disadvantage of a single-ingredient photosystem and hold fascinating prospects for solar energy conversion. Despite the advancements, bottom-up elaborate design of composite heterostructured Z-scheme photosystems by flexible interface engineering for photoredox organic transformation has been poorly investigated. We herein report the construction of a metal-based Z-scheme photoredox system via a progressive self-assembly strategy integrated with a facile photo-deposition. Tailor-made hierarchically branched ligand-capped Pd nanocrystals (NCs) sandwiched in-between a WO₃ nanorod (NR) core and CdS shell are harnessed as the charge transport modulator to regulate the interfacial oxidation–reduction kinetics for boosted Z-scheme photocatalysis. The intermediate Pd NCs as Schottky-type electron flow mediators considerably accelerate the unidirectional Z-scheme charge motion rate, endowing multilayered WO₃@Pd@CdS core–shell heterostructures with significantly boosted net efficiency of photoactivities toward anaerobic selective nitroaromatic reduction to amino derivatives and aromatic alcohol oxidation to aldehydes under visible light illumination. The predominant active species produced in the versatile photocatalytic selective organic transformation were explored and photocatalytic mechanisms were thus ascertained. Our endeavor could offer a promising route for smartly crafting diverse heterostructured Z-scheme photoredox systems for solar energy conversion.