水热辅助溶胶凝胶法制备纳米钛酸锌及其光催化性能

采用水热辅助的溶胶凝胶法制备纳米钛酸锌（ZnTiO₃）光催化剂，以罗丹明B为目标降解物，运用动力学模型分析罗丹明B（RhB）初始浓度对降解效果的影响。通过SEM、XRD、XPS、UV-Vis DRS对ZnTiO₃进行表征，并使用自由基捕获试验分析其降解机理。结果表明，ZnTiO₃为纯六方相，形貌为类球形，粒径50 nm左右。在催化剂用量为1 g/L、RhB初始浓度为5 mg/L、pH值为3的条件下，光催化反应150 min后，RhB降解率为93.2%。其动力学方程为k=0.132C₀^-1.253。ZnTiO₃光催化剂降解过程中，·OH、h⁺、·O₂^-均起到催化作用，产生·OH、h⁺的量相近且多于·O₂^-，说明·OH、h⁺在催化反应中起主要作用。

Preparation and photocatalytic properties of zinc titanate nanoparticles prepared by hydrothermal assisted sol gel process

The nano-zinc titanate (ZnTiO₃) photocatalyst was prepared by hydrothermal-assisted sol-gel method. Rhodamine B was taken as the target degradant. The effect of initial concentration of Rhodamine B (RhB) on the degradation was analyzed by kinetic model. ZnTiO₃ was characterized by SEM, XRD, XPS and UV-Vis DRS. The degradation mechanism was analyzed by free radical trapping experiments. The results show that ZnTiO₃ is a pure hexagonal phase with a spherical shape and a particle size of about 50 nm. Under the condition of catalyst dosage of 1 g·L^-1, initial concentration of RhB of 5 mg/L and pH of 3, the degradation rate of RhB was 93.2% after photocatalytic reaction for 150 min. Its kinetic equation is k=0.132C₀^-1.253. In the degradation process of ZnTiO₃ photocatalyst, ·OH, h⁺, ·O₂^- all play a catalytic role, and the amount of ·OH and h⁺ is similar and more than ·O₂^-, indicating that ·OH and h⁺ play a major role in the catalytic reaction.