Department of Chemical and Geological Sciences, University of Cagliari, S.P. 8 km 0.700, 09042 Monserrato, Italy.
Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (CSGI), Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.
Int J Mol Sci. 2022 May 12;23(10):5422. doi: 10.3390/ijms23105422.
Aurivillius oxides ferroelectric layered materials are formed by bismuth oxide and pseu-do-perovskite layers. They have a good ionic conductivity, which is beneficial for various photo-catalyzed reactions. Here, we synthesized ultra-thin nanosheets of two different Aurivillius oxides, BiWO (BWO) and BiMoO (BMO), by using a hard-template process. All materials were characterized through XRD, TEM, FTIR, TGA/DSC, DLS/ELS, DRS, UV-Vis. Band gap material (E) and potential of the valence band (E) were calculated for BWO and BMO. In contrast to previous reports on the use of multi composite materials, a new procedure for photocatalytic efficient BMO nanosheets was developed. The procedure, with an additional step only, avoids the use of composite materials, improves crystal structure, and strongly reduces impurities. BWO and BMO were used as photocatalysts for the degradation of the water pollutant dye malachite green (MG). MG removal kinetics was fitted with Langmuir-Hinshelwood model obtaining a kinetic constant k = 7.81 × 10 min for BWO and k = 9.27 × 10 min for BMO. Photocatalytic dye degradation was highly effective, reaching 89% and 91% MG removal for BWO and BMO, respectively. A control experiment, carried out in the absence of light, allowed to quantify the contribution of adsorption to MG removal process. Adsorption contributed to MG removal by a 51% for BWO and only by a 19% for BMO, suggesting a different degradation mechanism for the two photocatalysts. The advanced MG degradation process due to BMO is likely caused by the high crystallinity of the material synthetized with the new procedure. Reuse tests demonstrated that both photocatalysts are highly active and stable reaching a MG removal up to 95% at the 10th reaction cycle. These results demonstrate that BMO nanosheets, synthesized with an easy additional step, achieved the best degradation performance, and can be successfully used for environmental remediation applications.
钙钛矿型层状材料 Aurivillius 氧化物由氧化铋和赝立方钙钛矿层组成。它们具有良好的离子电导率，有利于各种光催化反应。在这里，我们通过硬模板法合成了两种不同的钙钛矿型层状材料 Aurivillius 氧化物 BiWO（BWO）和 BiMoO（BMO）的超薄纳米片。所有材料均通过 XRD、TEM、FTIR、TGA/DSC、DLS/ELS、DRS、UV-Vis 进行了表征。计算了 BWO 和 BMO 的带隙材料（E）和价带电位（E）。与之前关于使用多复合材料的报道相比，开发了一种新的用于高效光催化 BMO 纳米片的程序。该程序仅增加了一个步骤，避免了复合材料的使用，改善了晶体结构，大大减少了杂质。BWO 和 BMO 被用作光催化剂，用于降解水污染物孔雀石绿（MG）。用 Langmuir-Hinshelwood 模型拟合 MG 去除动力学，得到 BWO 的动力学常数 k = 7.81×10 -2 min -1 ，BMO 的 k = 9.27×10 -2 min -1 。光催化染料降解非常有效，BWO 和 BMO 对 MG 的去除率分别达到 89%和 91%。在没有光照的情况下进行的对照实验，允许量化吸附对 MG 去除过程的贡献。吸附对 BWO 中 MG 去除的贡献为 51%，对 BMO 仅为 19%，表明两种光催化剂的降解机制不同。由于 BMO 的高结晶度，导致其对 MG 的高级降解过程。重复使用测试表明，两种光催化剂均具有高活性和稳定性，在第 10 次反应循环中达到高达 95%的 MG 去除率。这些结果表明，通过简单的附加步骤合成的 BMO 纳米片具有最佳的降解性能，可成功用于环境修复应用。
