Abstract: Positron lifetime technique is one of a few methods sensitive to voids on the mono-atomic scale. The photocatalytic activity of BiVO4 was studied when the degradation of 2,4-dinitrophenol was used as a probe reaction. The effect of calcination temperature on the photocatalytic activity of BiVO4 was analyzed by positron annihilation spectrum. The results showed that the amount of surface defects and the microstructure of photocatalyst changed with the calcination temperature. More surface defects，amount of photo produced electrons-hole，heterogeneity and the electronic density of defect sites were found on BiVO4 calcined at 900 ℃ than other temperatures，which increased the photocatalytic oxidation activity of BiVO4，that is，the degradation rate of 2,4-dinitrophenol was increased.

摘要： 以2,4-二硝基苯酚光催化降解为探针反应，考察了BiVO4的光催化降解活性。利用正电子湮没谱分析了焙烧温度对BiVO4光催化活性的影响。结果表明，焙烧温度能引起特定的缺陷数目变化，改变了光催化剂的微观结构。经900 ℃焙烧的BiVO4催化剂比在其它温度下焙烧的催化剂有较多的表面缺陷数目，可产生表面光生电子-空穴的数目较多，不均匀性、缺陷位的电子密度大，使得其光催化氧化活性增强，即2,4-二硝基苯酚的降解率较高。