中文摘要：

光催化剂BiNbO4采用传统固相反应分别在900和1300℃下进行制备。通过XRD粉末衍射和UV—vis吸收光谱分析，表征了样品的物相和光谱吸收特性。通过对样品的测试分析表明，低温样品为正交相，高温样品为三斜相，正交相的禁带宽度（3．4eV）比三斜相（3．0eV）更宽。以降解甲基橙来评价BiNbO4的光催化活性，对比试验表明低温正交相BiNbO4的光催化活性远高于高温三斜相，这是由于它们晶体结构不同造成的。对正交相BjNbO4的光催化性能进行了深入的研究，实验发现催化剂浓度和溶液pH值对光催化剂的活性影响很大。通过第一原理的计算，讨论了BiNbO4的电子结构和光催化反应的关系。

英文摘要：

The BiNbO4 powders were prepared by a solid-state reaction method at 900 and 1300℃, and respectively characterized by X-ray powder diffraction and ultraviolet-visible diffuse reflection. It was found that BiNbO4 undergo an irreversible orthorhombic-triclinic phase transition, the powder calcined at 900℃ is orthorhombic phase while the powder calcined at 1300℃ is triclinic phase. The band gap of the orthorhombic phase （3.4eV） is broader than that of the triclinic phase （3.0eV）. The photocatalytic activities of BiNbO4 were systematically investigated on the degradation of methyl orange. The orthorhombic phase shows higher photocatalytic activity than the triclinic one. The dosage of the photocatalysts and the pH value in the solution greatly influenced the degradation rate. The electronic structures of both phases were studies by the first-principal calculations.