类微乳化学沉淀法合成BiOBr-TiO_2纳米复合材料及其光催化性能

Synthesis of BiOBr-TiO_2 Nanocrystalline Composite by Microemulsion-Like Chemical Precipitation Method and Its Photocatalytic Activity

采用简单的类微乳化学沉淀法获得了有效复合的BiOBr-TiO2纳米材料.该合成方法的关键在于Br-的双重作用.Br-既作为"桥"将十六烷基三甲基溴化铵(CTAB)中CTA+与TiO2粒子相连,构筑了稳定的油包水的类微乳体系.同时,它又作为BiOBr的溴源有助于纳米复合材料异质结的形成.与纯TiO2和传统的水相化学沉淀法获得的BiOBr-TiO2复合样品相比,采用类微乳化学沉淀法获得的复合光催化剂表现出高的光生电荷分离效率,相应地显示出优异的光催化降解气相乙醛和液相苯酚的性能,这主要与BiOBr和TiO2粒子之间异质结的有效构筑有关.

Nanocrystalline BiOBr-TiO2 composite has been prepared using a microemulsion-like chemical precipitation method. The key to this method is the dual role of Brin the synthetic process. The Br- of cetyl trimethyl ammonium bromide is able to link the cetyltrimethyl ammonium cation with anatase TiO2 to form a water-in-oil microemulsion-like system. Meanwhile, Bris also a bromine source favorable for the fabrication of a nanoheterostructure between BiOBr and TiO2. Compared with pure TiO2 and BiOBr-TiO2 composite obtained using a traditional aqueous system, the as-obtained BiOBr-TiO2 displays high photogenerated charge separation, responsible for excellent photocatalytic activity for degrading liquid-phase phenol solution and gas-phase acetaldehyde. This result is ascribed to its effective heterostructure.