Z-scheme visible-light-driven Ag3PO4 nanoparticle@MoS2 quantum dot/few-layered MoS2 nanosheet heterostructures with high efficiency and stability for photocatalytic selective oxidation

Abstract A novel MoS2 quantum dots/few-layered MoS2 nanosheets (MQD/FL-MNS)-coated Ag3PO4 nanoparticles (ANP) core@shell heterostructure with high photocatalytic activity and stability under visible light irradiation was fabricated by a simple stirring–ultrasonic exfoliation method and an organic phase in situ growth strategy. TEM, AFM, and Raman characterizations verified the successful preparation and the high quality of the two-dimensional MQD/FL-MNS exfoliated from bulk MoS2. An appreciable direct bandgap of 1.93 eV for MQD/FL-MNS is observed, which is favorable for its photocatalytic application. The obtained ANP@MQD/FL-MNS nanocomposites exhibited significantly enhanced performance for photodegradation of organic pollutants (RhB) and photocatalytic selective oxidation of benzyl alcohols (BA) to benzaldehyde compared with pure Ag3PO4, and the ANP@MQD/FL-MNS-6 nanocomposite exhibited the highest photocatalytic activity. The energy band structure and the quenching effects of different scavengers demonstrated that the electrons of MoS2 and the holes of Ag3PO4 with higher oxidability and reducibility are the real participants in photocatalytic reactions. The superior photocatalytic activity of the novel catalyst originates from the particular Z-scheme charge carrier migration mechanism and core@shell heterostructures with an intimate and large contact interface, resulting in highly efficient interfacial charge transfer and the separation of photogenerated electrons and holes. In addition, the introduction of MQD/FL-MNS could boost light harvesting, provide more active adsorption sites, facilitate dissolved O2 activation, and protect the Ag3PO4 from dissolution and photocorrosion during the photocatalytic oxidation reaction