Abstract: Bismuth oxide bismuth molybdate (Bi2MoO6) is a typical Bi(III) based semiconductor with visible light driving characteristics, which has advantages such as good ion conductivity, narrow bandgap, and environmental friendliness. However, the practical application of Bi2MoO6 monomer is severely limited due to its poor intrinsic photo-generated carrier separation, high recombination rate, and narrow light response range. Constructing heterojunctions is an effective method to improve their photocatalytic performance, which not only expands the light absorption range but also promotes the separation of photo-generated charge carriers. However, the construction of heterojunctions has the drawback of lattice mismatch at the interface of two substances, which hinders charge transfer between the interfaces. The one-step synthesis of composite catalysts can effectively reduce the lattice mismatch at the interface, promote the spatial separation of photo-generated electrons and holes, and expand the light absorption range of catalytic materials. In this study, Bi2MoO6/Bi7O9I3 heterojunction materials were synthesized by one-step method. The morphology, chemical composition and photoelectric properties of the heterojunction materials were characterized by instrumental analysis. The effect of material adsorption and photocatalytic degradation of ciprofloxacin (CIP) was studied. The results showed that compared with the single component, Bi2MoO6/Bi7O9I3 composite improved the visible light absorption capacity of Bi2MoO6 monomer, reduced its band gap width, and improved the activity of CIP adsorption and photocatalytic degradation. When the molar ratio of Bi2MoO6 to Bi7O9I3 was 7:3, the best removal rate of CIP was obtained. The absorption removal and photocatalytic degradation rates of CIP were 82.6% and 94.7%. Under the same conditions, the adsorption and degradation rates of monomer Bi2MoO6 and Bi7O9I3 were only 57.4% and 66.4%, 35.2% and 43.6%, respectively. Free radical capture experiments showed that the main active species of Bi2MoO6/Bi7O9I3 photocatalytic degradation of ciprofloxacin were h+ and ?O2-.

Key words: Bi2MoO6, Bi7O9I3, photocatalysi, heterojunction

摘要： 本工作采用一步法合成了Bi2MoO6/Bi7O9I3异质结材料，并采用多种手段表征异质结材料的形貌结构、化学组成和光电性能，研究了该异质结材料吸附和光催化降解环丙沙星(CIP)的效果。结果表明，与Bi2MoO6单体相比，Bi2MoO6/Bi7O9I3复合异质结材料提高了对可见光的吸收能力，减小了其带隙宽度，从而同时提高了其作为催化材料吸附和可见光下降解CIP的活性。研究发现该复合材料中Bi2MoO6与Bi7O9I3摩尔比为7:3时对CIP的去除效果最好，其中吸附去除率为82.6%，光催化降解率为94.7%。而在相同条件下，Bi2MoO6、Bi7O9I3吸附去除和催化降解环丙沙星的效率分别仅为57.4%, 66.4%和35.2%, 43.6%。自由基捕获实验表明Bi2MoO6/Bi7O9I3光催化降解环丙沙星的过程中主要活性物种为h+和?O2-。

关键词: Bi2MoO6, Bi7O9I3, 光催化, 异质结