六方相/单斜相WO_(3)“异相结”的可控合成及光催化性能

Controllable Synthesis and Photocatalytic Properties of Hexagonal/Monoclinic WO_(3) Phase Junction

利用沉淀法合成了球形六方相氧化钨(h-WO_(3)),通过调控六方相向单斜相的相变,可控制备了六方/单斜WO_(3)(h/m-WO_(3))“异相结”催化剂。采用X射线衍射(XRD)、扫描电镜(SEM)和比表面积(BET)等对WO_(3)催化剂的晶相结构及组成、粒子大小和比表面积进行了表征。光催化分解水产氧的实验结果表明,相较于纯六方相WO_(3),具有合适晶相组成的h/m-WO_(3)展现了显著的光催化性能。结合六方相和单斜相的能带位置,表面光电压表征结果发现,h/m-WO_(3)“异相结”的形成显著促进了催化剂表面光生电子和空穴的高效分离,进而提高了催化剂的光催化活性。

The spherical hexagonal phase tungsten oxide(h-WO_(3))was synthesized by precipitation method.Then a series of hexagonal/monoclinic WO_(3)(h/m-WO_(3))phase junction photocatalysts were controllable fabricated by regulating the phase transition process from hexagonal to monoclinic phase.The crystal phase structure and phase composition,particle size and specific surface area of these WO_(3)catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and specific surface area(BET).The experimental results of photocatalytic O2 evolution show that compared with the pure hexagonal phase WO_(3),the h/m-WO_(3)with suitable crystal phase composition exhibits remarkable photocatalytic performance.Based on the band positions of hexagonal and monoclinic phases,the surface photovoltage(SPV)characterization results show that the formation of h/m-WO_(3)phase junction significantly promotes the efficient separation of photogenerated electrons and holes on the surface of the catalyst,and then improves the photocatalytic activity of WO_(3)catalyst.