Precipitation Synthesis of Mesoporous Photoactive Al2O3 for Constructing g-C3N4-Based Heterojunctions with Enhanced Photocatalytic Activity

Abstract

Mesoporous γ-Al2O3 with high surface area (159 m2/g) is prepared via a precipitation method. The as-synthesized Al2O3 exhibits optical absorption ability in the ultraviolet region and is used as the active component to be combined with g-C3N4 to form effective heterostructured photocatalysts. This heterojunction structure is confirmed by X-ray diffraction, scanning electron microscopy, element map, transmission electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy measurements. The photocatalytic performances of the composites are evaluated by the degradation of rhodamine B (RhB) and methyl orange (MO). Among the prepared photocatalysts, 2g-C3N4:1Al2O3 (weight ratio) exhibits the highest photocatalytic activity, the reaction rate constant of which is 2.5 and 3.7 times that of pure g-C3N4 in degradation of RhB and MO, respectively. The enhancement in activity of heterojunctions is ascribed to their high specific surface areas...