ZnO异质复合对纳米TiO_2晶型转变和晶粒生长的影响

EFFECTS OF HETEROGENEOUS COMPOSITE AGENT ZnO ON PHASE TRANSITION PROCESS AND PARTICLE GROWTH OF TiO_2 NANOCRYSTAL

以TiCl4,ZnSO4溶液为原料,采用液相沉淀法制备了不同ZnO/TiO2摩尔比的纳米复合粉体。对合成的纳米复合晶的相变、晶粒生长过程以及紫外-可见光吸收性能进行了研究。结果表明:纳米TiO2经ZnO复合后,其晶型转变和晶粒生长均受到抑制。当ZnO为30%(摩尔分数)时,且采用氨水滴入TiCl4和ZnSO4溶液中的沉淀方式制备的ZnO/TiO2纳米复合晶的晶型转变和晶粒生长最缓慢。紫外-可见光吸收测试表明:800℃煅烧的ZnO/TiO2复合粉体的吸收强度比纯TiO2的高;900～1050℃煅烧的复合粉体,虽然紫外区的吸收强度有所下降,但其光吸收带边比纯TiO2纳米晶的有显著红移。

ZnO/TiO2 nanocomposite powders were prepared by the precipitation method and using TiCI4, ZnSO4 and H2SO4 as raw materials. The phase transformation, particle growth and ultraviolet-visible （UV-VIS） absorbance ofZnO/TiO2 nanocomposite powders were studied. The results show that the phase transformation and grain growth of TiO： are inhibited after adding ZnO. When the content of ZnO is 30 % （in mole） and the ammonia solution is dipped into TiCI4 and ZnSO4 solutions, phase transformation and grain growth of TiO2 are remarkably inhibited. The UV-VIS absorbance spectrum shows that the absorbance of the composite calcined at 800℃; is higher than pure TiO2, and is lower when calcined at 900-1 050℃. In this temperature range, the absorbance of the composite; is also decreased, but there is a large red-shift of its photoabsorption band edge.