AgI/BiOI异质结催化剂的制备及其可见光催化降解酸性橙Ⅱ的性能研究

Preparation of AgI/BiOI Heterojunction Photocatalysts and Their Photocatalytic Degradation of Acid Orange Ⅱ under Visible Light

文章采用水热法制备了AgI/BiOI异质结催化剂,并通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、紫外-可见漫反射光谱(DRS)对AgI/BiOI异质结催化剂进行形态特征及光学性质表征。结果表明,制备的AgI/BiOI为高纯度、纳米片层组成的微球结构。DRS结果表明BiOI对可见光有明显的吸收,掺杂AgI后AgI/BiOI异质结催化剂在可见光范围产生红移。以酸性橙Ⅱ为目标污染物,考察了AgI/BiOI的可见光催化活性。研究表明,AgI/BiOI对酸性橙Ⅱ在2 h降解效率可达到90%以上,明显高于单独AgI或BiOI对酸性橙Ⅱ的降解效率。AgI/BiOI异质结催化剂的电化学交流阻抗谱分析表明AgI/BiOI比纯BiOI具有更低的交流阻抗值,因此AgI/BiOI异质结催化剂具有较好的催化活性。

In this study, the nanostructured AgI/BiOI heterojunction photocatalyst was prepared by solvothermal process. AgI/BiOI heterojunetion photoeatalyst was characterized using X-ray power diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and UV-vis diffuse reflectance spectroscopy （DRS）. The results indicated that the BiOI product had high purity and composed of nanoplates. The DRS results indicated that BiOI had the significant adsorption in the visible light region, and AgI/BiOI heterojuction photocatalysts possessed the red-shift in the visible light. The photocatalytic activity of AgI/BiOI was evaluated by photocatalytic degradation of acid orange II under visible light irradiation （λ 〉 400 nm）. It was observed that the photocatalytic degradation efficiency of acid orange II was more than 90% within 2 h, which was higher than that of AgI and BiOI. The en- hanced photocatalytic activity mechanism was studied by the electrochemical impedance spectroscopy （EIS）. The EIS results showed that the impedance value of AgI/BiOI was much lower than that of pure BiOI, leading to the enhanced photocatalytic activity of AgI / BiOI heterojunction photocatalysts.