基于可见光磁性纳米γ-Fe2O3/TiO2纳米管复合光催化剂

High visible-light photocatalytic activity of nano γ-Fe2O3/TiO2 nanotube heterojunction arrays

摘要:

本文研究了基于可见光的磁性复合光催化剂——纳米γ-Fe2O3/TiO2 (NT)异质结阵列的制备方法，还研究了磁性复合光催化剂的表面形貌、微观结构、磁性能及其对亚甲基蓝的催化降解活性作用。研究结果表明，磁性复合光催化剂中的TiO2纳米管阵列呈高度有序，其直径约55nm、壁厚约10nm，沉积在上面的γ-Fe2O3颗粒粒径约15nm。复合光催化剂MHP呈超顺磁性，其超顺磁性来源于γ-Fe2O3的小尺寸效应。在可见光的照射下γ-Fe2O3/TiO2 (NT)的光催化性能明显大于的Fe3O4/TiO2 (NT)或纯TiO2（NT）。γ-Fe2O3和TiO2 (NT)之间的相互作用有利于电荷分离，并将TiO2(NT)红移至到可见光区。此外，γ-Fe2O3和TiO2 (NT)之间所形成的异质结结构有利于阻止光电子和空穴之间的复合。

Abstract:

This study presents the preparation and application of nano γ-Fe2O3/TiO2 nanotube magnetic heterojunction photocatalysts (MHPs) for photodegradation of methylene blue under visible light irradiation. The morphology, microstructure, magnetic properties, and photocatalytic activity of γ-Fe2O3/TiO2 (NT) MHPs were studied. The results showed that the MHPs were provided with highly ordered TiO2 (titania) nanotube arrays (55 nm diameter and 10 nm wall thickness) and nano γ-Fe2O3 (maghemite) particle (approximately 15 nm) co-deposition. The MHPs exhibited a superparamagnetic behavior of γ-Fe2O3/TiO2 (NT) MHPs resulting from the small size of γ-Fe2O3 particles. The photocatalytic activity of γ-Fe2O3/TiO2 (NT) MHPs was greater than that of Fe3O4/TiO2 (NT) MHPs or pure TiO2 (NT) under visible light irradiation. The interaction between γ-Fe2O3 and TiO2 improved charge separation and extended TiO2 response into the visible region. Moreover, the formed heterojunction between γ-Fe2O3 and TiO2 could further prevent the recombination between photoelectrons and holes.