通过一步溶剂热法由BiOI和Bi/BiOI-X(其中x可以是1、2、3或4)制备复合材料,并用于设计铬(VI)的光电化学(PEC)测定。通过X射线衍射对材料的化学组成和形貌进行了表征,X射线光电子能谱,扫描电子显微镜,和透射电子显微镜。UV-visDRS(漫反射光谱)和光致发光的结果表明,与单独的BiOI相比,复合材料具有更高的可见光吸收和更低的电子复合率。光生电子将六价铬还原为三价铬,添加Cr(VI)后,电子的消耗导致光电流密度显着提高。因此,Cr(VI)浓度可以通过监测光电流密度的增加来测量。Bi/BiOI-3材料显示出检测Cr(VI)的最佳性能。该方法具有较宽的线性范围(1至230μM)和0.3μM的低检出限(S/N=3)。它是稳定的,选择性,重现性好,用于加标自来水和湖水样品中亚硝酸盐的测定。基于Bi/BiOI的电化学传感器的示意图,用于测定Cr(VI)。
Composites were prepared from BiOI and Bi/BiOI-X (where x can be 1, 2, 3, or 4) by a one-step solvothermal method and used to design a photoelectrochemical (PEC) assay for chromium(VI). The chemical composition and morphology of the materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results of UV-vis DRS (Diffuse reflection spectra) and photoluminescence show the composites to have higher visible light absorption and a lower electron recombination rate compared to BiOI alone. Photogenerated electrons reduce hexavalent chromium to trivalent chromium, and the consumption of electrons cause noticeable enhances of the photocurrent density after the addition of Cr(VI). Thus, the Cr(VI) concentration can be measured by monitoring the increase of photocurrent density. The Bi/BiOI-3 material displays the best performance for detecting Cr(VI). The method has a wide linear range (1 to 230 μM) and a low detection limit of 0.3 μM (at S/N = 3). It is stable, selective, reproducible and was applied to the determination of nitrite in spiked tap water and lake water samples. Graphical abstract Schematic presentation of a electrochemical sensor based on Bi/BiOI for the determination of Cr(VI).