We describe preparation of chlorophyll/flavonoid-sensitized ZnO nanoparticles with visible-light-induced photocatalytic activity. ZnO catalysts were sensitized by an incipient wetness impregnation in which chlorophyll and flavonoid natural pigments were extracted from parsley leaves and Curcuma longa roots, respectively. Structural studies were conducted using characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). Diffuse reflectance spectra (DRS) were employed to analyze optical characteristics indicating a decrease in bandgap energies of as-sensitized samples towards visible light absorption compared with nonsensitized ZnO catalysts. The photocatalytic property of chlorophyll/flavonoid-sensitized ZnO nanoparticles was evaluated by measuring photodegradation of methylene blue (MB) as a function of involved operating parameters including irradiation time, photocatalyst concentration, pH, and initial MB concentration in aqueous media. Chlorophyll-sensitized catalysts showed higher photodegradation efficiency in comparison with the flavonoid-sensitized sample relevant to a larger optical absorption edge. The photocatalytic results also indicated less optimum irradiation time in the presence of flavonoid-sensitized catalysts compared with that in the presence of the chlorophyll-sensitized sample due to stronger absorption ability of photons in a region around the optical absorption edge. The kinetic expressions were studied using the Langmuir-Hinshelwood theory, and an appropriate model was presented for the MB photodegradation process.

我们描述了具有可见光诱导的光催化活性的叶绿素/类黄酮敏感的ZnO纳米粒子的制备。ZnO催化剂通过初期湿润浸渍而敏化，其中从欧芹叶和姜黄中提取叶绿素和类黄酮天然色素根。使用包括X射线衍射（XRD），傅立叶变换红外光谱（FT-IR）和扫描电子显微镜（SEM）在内的表征技术进行了结构研究。漫反射光谱（DRS）用于分析光学特性，表明与未敏化的ZnO催化剂相比，敏化的样品对可见光吸收的带隙能量减小。叶绿素/类黄酮敏化的ZnO纳米颗粒的光催化性能通过测量亚甲基蓝（MB）的光降解来评估，该光降解是所涉及的操作参数的函数，包括辐射时间，光催化剂浓度，pH和在水性介质中的初始MB浓度。叶绿素敏化的催化剂显示出更高的光降解效率，而黄酮类敏化的样品与较大的光吸收边缘有关。由于在光吸收边缘附近的区域中光子的吸收能力强，因此与存在叶绿素敏化样品的情况相比，在存在类黄酮敏化催化剂的情况下，光催化结果还表明最佳照射时间较短。使用Langmuir-Hinshelwood理论研究了动力学表达，并提出了用于MB光降解过程的合适模型。由于在光吸收边缘附近的区域中光子的吸收能力强，因此与存在叶绿素敏化样品的情况相比，在存在类黄酮敏化催化剂的情况下，光催化结果还表明最佳照射时间较短。使用Langmuir-Hinshelwood理论研究了动力学表达，并提出了用于MB光降解过程的合适模型。由于在光吸收边缘附近的区域中光子的吸收能力强，因此与存在叶绿素敏化样品的情况相比，在存在类黄酮敏化催化剂的情况下，光催化结果还表明最佳照射时间较短。使用Langmuir-Hinshelwood理论研究了动力学表达，并提出了用于MB光降解过程的合适模型。