Anchoring of Ag6Si2O7 nanoparticles on α-Fe2O3 short nanotubes as a Z-scheme photocatalyst for improving their photocatalytic performances

Abstract

Coupling two different semiconductors to form composite photocatalysts is the most significant method for environmental remediation. In this regard, tube-like α-Fe₂O₃/Ag₆Si₂O₇ heterostructures are synthesized via anchoring p-type Ag₆Si₂O₇ nanoparticles (NPs) on the surface of n-type α-Fe₂O₃ short nanotubes (SNTs) by conventional wet-chemical routes. α-Fe₂O₃ SNTs are firstly fabricated by a hydrothermal method with the assistance of dihydrogen phosphate and sulphate. Then, Ag₆Si₂O₇ NPs are anchored on α-Fe₂O₃ SNTs by an in situ deposition method, and the α-Fe₂O₃/Ag₆Si₂O₇ p–n heterostructures are finally obtained. The morphologies, crystal structure, photocatalytic performance and photocurrent properties of as-synthesized α-Fe₂O₃/Ag₆Si₂O₇ heterostructures are investigated. Six organic dyes are used for determining the high-efficiency Z-scheme photocatalytic activities of the as-obtained photocatalysts under ultraviolet and visible light (mercury lamp, 300 W). Compared with pure α-Fe₂O₃ SNTs, the photocurrent intensity of the α-Fe₂O₃/Ag₆Si₂O₇ heterostructures is improved 62 times. The enhanced significant photocatalytic performance of α-Fe₂O₃/Ag₆Si₂O₇ heterostructures could be attributed to charge transfer between Ag₆Si₂O₇ NPs and the charge separation between Ag₆Si₂O₇ NPs and α-Fe₂O₃ SNTs. These composite heterostructures are proposed to be an example for the preparation of other composite silicate photocatalysts for practical application in environmental remediation issues.