Prominent ferroelastic domain walls in BiVO₄crystal

Abstract

The domain structure of ferroelastic BiVO4 crystals was investigated by X-ray diffraction, nuclear magnetic resonance, optical polarizing microscopy, transmission electron microscope, and electron diffraction techniques. From these results, it is found that the BiVO4 crystals have only prominent W walls and no non-prominent W' domain walls. A model of the twin structure is suggested, and all experimental results are explained in terms of this model. However, the prominent W wall obtained from our experimental results should not occur in the ferroelastic species 4/mF2/m previously reported. From the acoustic symmetry character of the elastic behaviour, it has been established that there exist two possible W and W' walls for permissible planar walls that are consistent with all experimental observations. Thus, it can be concluded that the BiVO4 crystals having only the W walls found by our group and W' walls obtained by other groups are consistent with the ferroelastic species 4/mmmF2/m rather than 4/mF2/m.

Recent Advances in the BiVO4 Photocatalyst for Sun-Driven Water Oxidation: Top-Performing Photoanodes and Scale-Up Challenges

“…Interest in the study of BiVO 4 was initially due to the ferroelastic properties of the material, and its ferroelastic-paraelastic transition reported at 528 K (255 • C) [18], a property that depends on the crystal structure. BiVO 4 has three main crystal forms: a monoclinic scheelite, a tetragonal zircon-type and a tetragonal scheelite structures [18,19].…”

“…Interest in the study of BiVO 4 was initially due to the ferroelastic properties of the material, and its ferroelastic-paraelastic transition reported at 528 K (255 • C) [18], a property that depends on the crystal structure. BiVO 4 has three main crystal forms: a monoclinic scheelite, a tetragonal zircon-type and a tetragonal scheelite structures [18,19]. An irreversible transition from the tetragonal zircon-type to the monoclinic scheelite structure occurs at calcination temperatures of about 400-500 • C. Moreover, a reversible transition occurs between the monoclinic-scheelite and the tetragonal scheelite structures at a temperature of 255 • C, the same temperature that is responsible for the ferroelastic-paraelastic transition.…”

A ternary Er3+-BiVO4/TiO2 complex heterostructure with excellent photocatalytic performance

“…[7][8][9][10] Different synthetic routes leads to BiVO 4 in two crystalline phases: monoclinic (space group I2/b) and tetragonal (space group I4 1 /a) scheelite. 11,12 Among the above crystal phases, the monoclinic BiVO 4 is the best visible-lightdriven photocatalyst. The results reported by Yu et al demonstrated that the crystalline structure is the vital factor controlling MB degradation and O 2 evolution reactions.…”

BiVO4 as a Visible-Light Photocatalyst Prepared by Ultrasonic Spray Pyrolysis

“…[10][11][12] BiVO 4 is well-known for its ferroelastic properties 13 and its use as a nontoxic, bright yellow pigment 14,15 and has received some attention as a visible-light active photocatalyst. [16][17][18] The oxide has been synthesized by various means, including traditional solid state, [19][20][21] hydrothermal, 22,23 sonochemical, 24 and aqueous/coprecipitation. 16,25,26 With a bandgap of 2.4 eV, BiVO 4 absorbs well into the visible spectrum and has shown significant visible-light activity for O 2 evolution from AgNO 3 solutions, which act as the oxidizing agent.…”