Effects of distortion of PO4 tetrahedron on the photocatalytic performances of BiPO4

Three kinds of crystal phase BiPO4 (HBIP, nMBIP and mMBIP) were selectively synthesized by a hydrothermal method. The governed factors for the formation of three crystal phase of BiPO4 were both on the acidity of the solution and reaction temperature. The BiPO4 with nMBIP phase structure showed higher activity for degradation of MB solution under UV irradiation than HBIP and mMBIP. The catalytic activity per surface area activity of nMBIP (3.8 x 10(5) h(-1) m(-2)) was about ten times higher than that of P25(1.4 x 10(-4) h(-1) m(-2)). The BiPO4 with nMBIP structure exhibited the highest activity due to the most distorted PO4 tetrahedron. The induce effect of the dipole moment derived from the distorted PO4 tetrahedron promoting the separation of e(-)/h(+) pairs and further benefited for the photocatalytic reaction. This correlation may help to design and develop other oxoacid salt photocatalysts with high activity.