基于氯化BiOBr/TiO_(2)的新式臭氧转化反应

The new mechanism of ozone conversion based on chlorinated BiOBr/TiO

利用溶胶凝胶法制备了BiOBr/TiO_(2)复合型光催化剂并进行氯化改性,紫外照射下表现出了较高的臭氧转化能力.随后利用XRD、UV-Vis DRS、TEM、EPR、电化学等方法对催化材料进行表征,分析其光催化反应原理.结果表明,BiOBr/TiO_(2)对臭氧的转化率提升至61%,这是由于二者形成了半导体异质结,光生电子传递降低了载流子复合率,羟基自由基生成量增加;氯化材料的转化率进一步大幅提升至99%,这是由于氯元素在光照条件下生成氯自由基,进而驱动了一种效率更高的链式传递反应.该反应体系在较高湿度下未见明显失活,优于传统α-MnO_(2),具有应用潜力.

In this article,BiOBr/TiO_(2) was prepared via a sol-gel method and then modified by surface chlorination.The conversion of ozone under UV irradiation increased to 61%(BiOBr/TiO_(2)) and 99%(chlorinated BiOBr/TiO_(2))respectively compared to pure TiO_(2).Besides,no obvious deactivation observed over new photocatalyst under high humidity,which was superior to α-MnO_(2).Finally an electrochemical workstation,Fourier transform infrared spectrometry(FT-IR),X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)were used to determine the mechanism of the outstanding photocatalysis.As confirmed,heterojunction in BiOBr/TiO_(2) would enhance photocatalysis via reducing the recombination of photo-carriers.And the Cl chemically adsorbed on the catalytic surface would be transformed into Cl radicals to drive a more efficient chain transfer reaction,which dramatically improved photocatalytic conversion of ozone.