Background: Different photocatalysts such as TiO₂, ZnO and WO₃ have been used for the degradation of organic pollutants. However, these materials have some limitations, which have been affected the catalytic efficiency in the various transformations. The composites of these materials with other oxides can produce better results by tuning structural as well as optoelectrical properties. The composite of TiO₂ with ZrO₂ has attracted attention due to its use in different areas, as ZrO₂ and TiO2 have similar physicochemical features.

Methods: This research contains the preparation of ZrO₂-TiO₂ nanocomposites by hydrothermal method and analysis of photocatalytic activity for the degradation of methylene blue and a mixture of dyes under visible light irradiation.

Results: Physicochemical characterization of ZrO₂-TiO₂ nanocomposites has been studied by using different techniques. Prepared catalysts has shown anatase phase of TiO₂ and tetragonal phase of ZrO₂. XRD, FESEM and HRTEM have supported the nanocrystalline nature of the composites. The photocatalytic activity of composites and bare TiO₂ samples were demonstrated for the degradation of methylene blue dye. Enhanced activity has been shown by composite having Ti:Zr 3:1 molar proportion, i.e., Ti3Zr. Effect of concentration of methylene blue, pH of the solution and catalyst loading have been studied by using Ti3Zr. In addition, the degradation of a mixture of three dyes, namely methylene blue, rhodamine B and methyl orange, has been studied.

Conclusion: In summary, prepared ZrO₂-TiO₂ composites found to be nanocrystalline and visible light active. These catalysts have shown activity for photocatalytic degradation of methylene blue and a mixture of dyes.

背景：TiO ₂，ZnO和WO ₃等不同的光催化剂已被用于降解有机污染物。然而，这些材料具有一些局限性，这些局限性已经影响了各种转化中的催化效率。这些材料与其他氧化物的复合材料可以通过调整结构和光电性能产生更好的结果。TiO ₂与ZrO ₂的复合材料由于其在不同领域的使用而引起了人们的关注，因为ZrO ₂和TiO2具有相似的理化特性。

方法：采用水热法制备ZrO ₂ -TiO ₂纳米复合材料，并在可见光照射下分析其对亚甲基蓝和染料混合物的光催化活性。

结果：采用不同技术研究了ZrO ₂ -TiO ₂纳米复合材料的理化性质。制备的催化剂显示出TiO _2的锐钛矿相和ZrO _2的四方相。XRD，FESEM和HRTEM支持了复合材料的纳米晶体性质。复合材料和TiO ₂裸露物的光催化活性样品被证明可降解亚甲基蓝染料。具有3∶1摩尔比的Ti∶Zr的复合材料，即Ti3Zr，显示出增强的活性。通过使用Ti3Zr，研究了亚甲基蓝的浓度，溶液的pH值和催化剂负载量的影响。另外，已经研究了三种染料，即亚甲基蓝，若丹明B和甲基橙的混合物的降解。

结论：总之，发现制备的ZrO ₂ -TiO ₂复合材料具有纳米晶体和可见光活性。这些催化剂显示出对亚甲基蓝和染料混合物的光催化降解的活性。