Morphology-dependent photocatalytic removal of NO by hierarchical BiVO₄microboats and microspheres under visible light

In this study, hierarchical monoclinic BiVO4three-dimensional (3D) superstructures with two kinds of morphologies, namely BiVO4microboats and BiVO4microspheres, have been controllably synthesized by adjusting reaction time in the template-free hydrothermal process using ethylene glycol as solvent. The nucleation, growth, and self-assembly of the BiVO4superstructures could be readily controlled with reaction time, which brought different morphologies to the final product. The as-prepared BiVO4superstructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption experimentation, and UV-vis diffuse reflectance spectra (UV-vis DRS). The monoclinic 3D BiVO4catalysts are composed of two-dimensional (2D) nanoplates which intercross with each other. Nanoplates were firstly formed by aggregation of primary nanocrystallites and then self-assembly converted to microboats and microspheres via the oriented attachment mechanism. The prepared BiVO43D catalysts can respond to visible light and their optical and photocatalytic properties are relevant to their morphologies. The BiVO4microspheres showed superior photocatalytic activity on removal of gaseous NO compared to the BiVO4microboats. The morphology-dependent photocatalytic property of the BiVO4superstructures is discussed. This work suggests that the synthesized BiVO4micropheres are promising photocatalyst for environmental remediation.