Novel dodecahedron BiVO4:YVO4 solid solution with enhanced charge separation on adjacent exposed facets for highly efficient overall water splitting

- A new photocatalyst, BiVO4:YVO4 solid solution, is successfully prepared.
- A novel dodecahedron, BiVO4:YVO4, with only two facets exposed, is found.
- This BiVO4:YVO4 solid solution can split pure water under visible light.
- The facets exposed can separate photogenerated electrons and holes efficiently.

BiVO4, an excellent photocatalyst for oxygen production, has been studied extensively. Many attempts have been made to change the conduction band of BiVO4 to satisfy the H2O/H2 potential. In this paper, yttrium is introduced to adjust the energy band structure of BiVO4. A novel BiVO4:YVO4 solid solution with a new dodecahedron shape exposing two facets, {1 0 1} and {1 0 0}, is successfully prepared. On doping with Y, the crystal system of BiVO4 changes from monoclinic to tetragonal. The improved symmetry of the crystal system makes the (1 0 0) and (0 1 0) of {1 0 0} facets entirely identical, resulting in dodecahedron tetragonal BixY1−xVO4. The energy levels of the two facets show slight nonconformity. So the photogenerated electrons and holes can be separated efficiently between the adjacent exposed facets to produce H2 and O2, respectively. Through the study of photocatalytic performance, BixY1−xVO4 with Pt as co-catalyst shows highly efficient photocatalytic activity and can split pure water at the stoichiometric ratio.

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