催化剂的表面结构对于调控其催化活性具有重要的作用。采用高温煅烧的方法诱导锐钛相纳米TiO₂发生金红石相转变，对其光催化活性和金红石相含量分析发现，仅少量的金红石相生成可显著提高纳米TiO₂光催化活性，同时明显改变催化体系中不同自由基的相对含量。·OH的生成浓度仅有稍微增加，而O₂·^-的浓度从0.233 μM/h迅速增加到0.501 μM/h，说明煅烧过程诱导纳米TiO₂的表面结构发生显著改变，金红石相TiO₂优先在纳米TiO₂颗粒表面区域生成。通过与模型金红石相/锐钛相纳米TiO₂表面异质结构对比，进一步验证了表面晶相异质结构可显著提高纳米TiO₂催化活性。

The surface structure of the catalyst plays an important role in adjusting and controlling its catalytic activity.Herein,the sintering treatment method is used to induce anatase nano-TiO₂ to transform into rutile phase.The phase transformation is verified by XRD patterns.It is found from analyzing the photocatalytic activity and the content of rutile phase that even a small amount of rutile phase is formed,the photocatalytic activity of nano-TiO₂ can be improved greatly and the relative content of different free radicals in the catalytic system will be obviously changed.The generation concentration of ·OH enhances slightly but the generation concentration of O₂-increases significantly from 0.233 μM·h^-1 to 0.501 μM·h^-1,which suggests an obvious structure change occurs on nano-TiO₂ surface during sintering process,probably anatase-to-rutile phase transformation occurs preferentially in the surface area of nano-TiO₂ particles.Compared with the model rutile/anatase nano-TiO₂ surface heterostructure,it is further verified that the surface crystalline heterostructure can significantly improve the catalytic activity of nano-TiO₂.To further demonstrate the formation of surface phase heterostructure,a model anatase/rutile TiO₂ composite with surface heterostructure is fabricated for comparison,which verifies that the enhanced photocatalytic activity arises from the formation of surface anatase/rutile phase heterostructure.

卫毅梅(1990-),女,硕士,工程师,研究方向为流域水污染治理,jsqgzyx@163.com