화학공학소재연구정보센터
Applied Catalysis B: Environmental, Vol.132, 304-314, 2013
Bismuth vanadate hollow spheres: Bubble template synthesis and enhanced photocatalytic properties for photodegradation
Hollow sphere monoclinic scheelite BiVO4 (m-BiVO4) is simply synthesized via a simple hydrothermal method by using urea as guiding surfactant. The forming process is investigated to be the incorporation of bubble guiding, oriented attachment and Ostwald ripening. The heterostructured hollow spheres are built up of truncated octahedrons which are also found to be feasible based on theoretical calculation. The preferred truncated octahedron consists of {040}, {01 1}, and {1 1 0} crystal planes with multiplicities of 2, 2, and 4, respectively. Besides urea, different kinds of organic additives (citric acid, Vitamin C and oleic acid) are also chosen for the synthesis of m-BiVO4 to clarify the role of urea. The photocatalytic activities with different morphologies are evaluated on the degradation of Rhodamine B. It is found out that the m-BiVO4 with hollow structure shows the optimalizing activity and the reaction rate constant reaches up to 0.035 min(-1) without adding H2O2 as hydroxyl radicals provider. Except for activity, the as-prepared samples have high stability and durability, after four cycling runs of photodegradation of RhB, the photocatalytic ability of as-synthesized m-BiVO4 did not show any loss. The degradation of RhB is attributed to intrinsically strong photo-oxidation ability rather than photosensitization and the synthesized samples also shows efficient photocatalytic activity for the degradation of 2-propanol. Meanwhile, the reasons for the superior activity are also carefully investigated. (c) 2012 Elsevier B.V. All rights reserved.