Hydrothermal Preparation and Characterization of TiO₂/BiVO₄ Composite Catalyst and its Photolysis of Water to Produce Hydrogen

Abstract

In the present work, bismuth vanadate composited photocatalysts were synthesized and characterized. X-ray diffractometry and Raman results showed that the particles were well crystallized, and formed by the complex of monoclinic BiVO4 and TiO2 . On electron microscopy, the photocatalyst exhibited high crystallization, agglutination and irregular shape, and was surrounded by numerous TiO2 particles. The study of surface areas showed that the specific surface area of 30-BiVO4 /TiO2 composited was 112 m(2) ·g(-1) , which was nearly 10 times that of pure BiVO4 . The ultraviolet-visible diffuse reflectance spectra indicated the composited photocatalyst were activated in visible light. The activity of photocatalytic water splitting was studied. The results showed that monomer BiVO4 photocatalyst was not able to produce hydrogen under any light source. BiVO4 /TiO2 composited photocatalysts, however, were capable of generating hydrogen. Under UV light irradiation for 120 min, 1 g catalyst dispersed in 50 mL deionized water produced almost 1 mL hydrogen, such that the productivity of hydrogen was higher than that of P25-TiO2 . Photocatalytic decomposition of water under visible light also confirmed that the BiVO4 /TiO2 composited photocatalyst had the ability of water splitting.

Sunlight-Operated TiO2-Based Photocatalysts

“…FeO x -containing semiconductors are also actively investigated however the behavior of such systems combine frequently photocatalysis with photo-Fenton [ 81 ]. More complex formulations consider the combination of titania with, for example, heteropolyacids [ 82 , 83 ], vanadates such as BiVO 4 [ 84 , 85 ] or complex oxides such as CuNiOx [ 86 ] and FeAlO 3 [ 87 ]. Similar catalysts have been studied for ZnO-based materials.…”

Photocatalytic H2 production over inverse opal TiO2 catalysts

“…In this contest, also BiVO 4 is an attractive material for solar water splitting due to its small band gap (2.4 eV) which enables a wide absorption in the portion of the visible spectrum [21,22]. The good stability and the suitable valence band energy position to oxidize water are, in addition, key features either on its own or coupled with TiO 2 [23,24]. Furthermore, the combination of a highly ordered three dimensional macroporous titania (3DOM TiO 2 ) with BiVO 4 has achieved good results in the photodegredation of Rhodamine B under visible light irradiation [25].…”