碳纳米管修饰LaFeO3/TiO2复合材料的光催化性能与机理

采用超声辅助溶胶凝胶法制备了LaFeO₃颗粒,进一步以碳纳米管(CNTs)为基底和钛酸丁酯为前体,通过一步水热法煅烧合成CNTs/TiO₂/LaFeO₃(CTF)三元异质结光催化复合材料。通过扫描电子显微镜(SEM)、X射线衍射分析(XRD)、氮气吸附-解吸等温线(BET)、紫外-可见分光光度计(UV-Vis)、光致发光光谱(PL)等表征手段对材料的形貌与特征结构、比表面积和孔径结构以及光学特征进行了分析,并在紫外光下通过降解活性黑五(RB5)测试样品的光催化性能。结果表明,以CNTs作为载体,能够有效提升LaFeO₃/TiO₂复合材料的光催化性能。当CNTs在复合材料中的质量占比为5%时,150 W汞灯照射下RB5的50 min去除率可达99.5%。CNTs一方面通过增加复合材料的比较面积为催化反应的进行提供了更多的活性位点,更为重要的是,CNTs作为光生载流子传输的通道加快了电荷分离效率,提升了复合材料的降解能力和催化反应动力学进程。

Photocatalytic performance and mechanism of carbon nanotube modified LaFeO3/TiO2 composites

LaFeO₃ particles were prepared by the ultrasonic-assisted sol-gel method, and CNTs/TiO₂/LaFeO₃ (CTF) ternary heterojunction was successfully synthesized by one-step hydrothermal method using carbon nanotubes (CNTs) as substrate and TiO₂ as precursor.The morphology and structural characteristics, specific surface area, pore size structure, and optical characteristics of the composites were systematically investigated via scanning electron microscope(SEM), X-ray diffraction(XRD), nitrogen adsorption-desorption isotherm (BET), ultraviolet-visible spectrophotometer (UV-vis), and photoluminescence spectra(PL). The photodegradation of Reactive Black 5 (RB5) was carried out to evaluate the photocatalytic activity of the ternary heterojunction. Results show that LaFeO₃/TiO₂ composites loaded with CNTs displayed enhanced photocatalytic performance. In the presence of the composites with CNTs loading of 5%, the RB5 removal rate reached 99.5%within 50 min under mercury lamp irradiation at 150 W. CNTs can provide more active sites for catalytic reactions by increasing the relative area of composite materials,and more importantly, as a bridge of photocarrier transmission, CNTs can accelerate the charge separation efficiency and improve the degradation capacity of composite materials as well as the catalytic reaction kinetics process.