Herein, we report the synthesis, characterization, and application of TiO₂/ZnO and La-doped ZnO nanocomposites for the detection and degradation studies of Malachite Green (MG). TiO₂/ZnO and La-doped ZnO nanocomposites were synthesized by reflux and hydrothermal methods, respectively, and characterized by UV–visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analysis. A glassy carbon electrode modified with COOH-fMWCNTs and TiO₂/ZnO nanocomposite demonstrated high sensitivity characteristics for the sensing of MG up to 0.34 nM limit of detection. The application of a photocatalytic method using 2% La-doped ZnO led to 99% degradation of MG in 40 min. The photocatalytic breakdown of MG followed first-order kinetics as revealed from the spectroscopic and electrochemical monitoring of the degradation process. Color variation offered naked-eye evidence of MG degradation in the specified time. The experimental findings helped in proposing the degradation mechanism. To the best of our knowledge, the current work presents the first example of a novel photocatalyst for almost absolute degradation of MG. Moreover, the electrode modifier as well as the approach adopted is novel and efficient for minute-level detection of MG and monitoring of its photocatalytic degradation.

_{在此，我们报告了 TiO 2} /ZnO 和 La 掺杂 ZnO 纳米复合材料的合成、表征和应用，用于孔雀石绿 (MG) 的检测和降解研究。分别采用回流法和水热法合成了TiO ₂ /ZnO 和 La 掺杂 ZnO 纳米复合材料，并通过紫外-可见光谱、X 射线衍射、傅里叶变换红外光谱、扫描电子显微镜和能量色散 X 射线分析对其进行了表征. 用 COOH- f MWCNTs 和 TiO ₂修饰的玻碳电极/ZnO 纳米复合材料对 MG 的检测具有高达 0.34 nM 检测限的高灵敏度特性。使用 2% La 掺杂 ZnO 的光催化方法的应用导致 MG 在 40 分钟内降解 99%。MG 的光催化分解遵循一级动力学，如降解过程的光谱和电化学监测所揭示的那样。颜色变化提供了 MG 在指定时间内降解的肉眼证据。实验结果有助于提出降解机制。据我们所知，目前的工作是第一个用于几乎完全降解 MG 的新型光催化剂的例子。此外，电极改性剂以及采用的方法对于 MG 的分钟级检测和光催化降解的监测是新颖而有效的。