以ZnAl LDHs为前驱体,通过共沉淀法改变ZnAl LDHs的质量分数,制备了Ni/ZnAl LDHs复合光催化材料。以罗丹明B(RhB)为目标染料,研究了样品的光催化性能。通过XRD、比表面积、孔径分析、XPS和UV-Vis等技术讨论了Ni掺杂剂对结构的影响,并提出了光催化降解机理。结果表明,掺杂适量Ni不会破坏ZnAl LDHs的层状结构,但随着掺杂量的增加,结晶度和晶体尺寸减小。在RhB浓度为5mg/L,Ni/Zn/Al摩尔比为0.2∶2∶1,pH=7,催化剂用量为1g/L的条件下,Ni/ZnAl LDHs可以获得90%的RhB降解率。实验还发现,RhB可见光降解中的活性物质主要是羟基自由基,并且降解遵循一级反应动力学,同时也受扩散过程的影响。

Using ZnAl LDHs as precursor,Ni/ZnAl LDHs composite photocatalytic materials were prepared by changing the mass fraction of ZnAl LDHs by coprecipitation method.The photocatalytic activity of Rhodamine B (RhB) was studied.The influence of Ni dopant on the structure was discussed by XRD,surface area and pore size analysis,XPS and UV-Vis techniques.The photocatalytic degradation mechanism was proposed.The results shown that proper amount of Ni did not destroy the layered structure of ZnAl LDHs,but the crystallinity and crystal size decreased with the increase of doping amount.When the concentration of RhB was 5mg/L,the molar ratio of Ni/Zn/Al/Al was 0.2∶2∶1,pH value was 7,and the amount of catalyst was 1g/L,the degradation rate of RhB can be 90% by Ni doped ZnAl LDHs.It was found that the active substances in the visible light degradation of RhB were mainly hydroxyl radicals,and the degradation followed the first-order reaction kinetics and was also affected by the diffusion process.