复合光催化剂Cu_2(OH)PO_4/Ni(OH)_2的制备及其光催化性能

Synthesis of Cu_2(OH)PO_4/Ni(OH)_2 composites and enhanced photocatalytic activities

采用水热合成法在Cu2(OH)PO4表面原位沉积Ni(OH)2,制备异质结型的复合光催化剂Cu2(OH)PO4/Ni(OH)2;利用X线粉末衍射仪(XRD)、紫外-可见漫反射光谱仪(UV-Vis-DRS)和扫描电子显微镜(SEM)等,对其相结构、光吸收性能和微观形貌进行表征.结果表明:该复合光催化剂具有良好的紫外光吸收特性,是一类新型的光催化剂.复合光催化剂在紫外光下可以有效降解亚甲基蓝(MB)溶液,当Cu2(OH)PO4与Ni(OH)2的摩尔比为0.2时,Cu2(OH)PO4/Ni(OH)2具有最大催化活性.根据光催化中加入不同活性物种牺牲剂的实验,推测该异质结型材料光催化过程中光生载流子的传输方向及活性物种.Cu2(OH)PO4/Ni(OH)2的催化活性增强主要归结为复合时在两者之间形成有效的异质结,结区的内建电场能够促进光生载流子的分离,同时·OH和h+在光催化降解过程中是主要的活性物种.

Cu2(OH)PO4/Ni(OH)2composites were synthesized according to a surface in-situ precipitation principle using hydrothermal synthesis method.Several characterization tools including X-ray powder diffraction(XRD),UV-vis diffuse reflectance spectra(UV-vis DRS),and scanning electron microscope(SEM)was employed to study the phase structures,optical properties and morphologies of the samples.The results show that the Cu2(OH)PO4/Ni(OH)2composite is a new kind of photocatalyst which has good UV absorption property.The composites exhibited more efficient photocatalytic activities than pure Cu2(OH)PO4and Ni(OH)2for the degradation of Methylene Blue(MB)under UV light irradiation,and the 20% Cu2(OH)PO4/Ni(OH)2composite shows the highest photocatalytic activity.The photo generated carriers transfer direction and active species were proposed by photocatalysis experiments with different trapping agents.The results show that effective heterojunction at the interfaces of p-Cu2(OH)PO4and p-Ni(OH)2,and the inner electric field can promote the separation of photogenerated electron-hole pairs and then accounts for the enhancement of photocatalytic activity.Moreover,the·OH and h+are the primary radicals in the photocatalysis process.