BiVO4 Hollow Nanospheres: Anchoring Synthesis, Growth Mechanism, and Their Application in Photocatalysis

An anchoring method was developed to synthesize monoclinic BiVO4 (m-BiVO4) hollow spheres with a size of about 700 nm by employing colloidal carbon spheres (CCSs) as hard templates The Influence of synthesis conditions and the growth mechanism were investigated with XRD, TEM, and SEM through a series of comparison experiments It wits fouled that two-stage heat treatment was essential for the synthesis of BiVO4 hollow nanospheres The Bi3+ ions were firstly adsorbed oil the surface of the CCSs and worked as anchors in the first stage (80 C) In the second stage (100 degrees C), the VO3- ions reacted with the anchored Bi3+ ions, and amorphous BiVO4 nanoparticles were thus precipitated on the CCSs surface. The analysis on the calcination process revealed that calcination promoted the crystallization of amorphous BiVO4 into m-BiVO4 crystals at 236 degrees C and removed the CCSs at 353 degrees C. The as-prepared BiVO4 hollow nanospheres exhibited higher photocatalytic activity than BiVO4 prepared by the aqueous method and by a solid-state reaction in the degradation of rhodamine B and acetaldehyde, which could be attributed to their higher BET surface area (5.85 m(2)g(-1)) and larger band gap (2.36 eV) Given the general adsorption of metal ions oil the CCSs surface, this anchoring method could be extended to synthesize other hollow-structured multicomponent oxides. ((C) Wiley-VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2009)