Ordered Mesoporous BiVO₄ through Nanocasting: A Superior Visible Light-Driven Photocatalyst

Abstract

This paper describes a nanocasting synthesis of ordered mesoporous bismuth vanadate (BiVO4) crystals using bismuth nitrate hydrate and ammonia metavanadate as bismuth and vanadium sources and silica (KIT-6) as a template. Monoclinic scheelite BiVO4 crystals were formed inside the mesopores of silica through a mild thermal process, and BiVO4 was obtained after the removal of the hard template (silica) by NaOH treatment. As compared to conventional BiVO4, the product exhibited a superior photocatalytic performance in the photochemical degradation of methylene blue and photocatalytic oxidation of NO gas in air under visible light irradiation. The product was characterized by using X-ray diffraction, the Brunauer−Emmett−Teller method, UV−vis light reflectance, X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy. The relationship between the physicochemical property and the photocatalytic performance of the as-prepared samples is discussed.