Razafintsalama A Rija, Mishra Rajashree P, Sahoo Manas K, Mrinalini Madoori, Sahoo Bismaya, Ravelonandro Pierre, Chaudhary Yatendra S
Materials Chemistry Department, CSIR-Institute of Minerals Technology, Bhubaneswar, Odisha 751013, India.
Procédés et Ecologie Industrielle, Unité de Recherche en Génie des Procédés et Génie de l'Environnement, University of Antananarivo, Antananarivo 101, Madagascar.
Langmuir. 2023 Sep 12;39(36):12725-12739. doi: 10.1021/acs.langmuir.3c01462. Epub 2023 Sep 1.
The synergistically co-catalyst-decorated -based heterostructured photocatalysts have been synthesized by a hydrothermal approach with varied loading concentrations of to drive the hexavalent chromium reduction efficiently. The formation of the heterostructured photocatalyst was confirmed by the appearance of X-ray diffraction (XRD) peaks corresponding to the monoclinic phase and and also the antisymmetric (834 cm) and symmetric stretching (715 cm) of tetrahedral VO and D (1330 cm) and G (1570 cm) bands corresponding to in the Raman spectrum. The worm-like structures of nanocrystals grew onto the lamellar sheets of , as shown by field emission scanning electron microscopy (FESEM), and has an increased surface area of 15.62 mg in the case of . X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of V and Tistates, and the uniform distribution of nanocrystals over lamellar sheets of is evident from energy-dispersive X-ray (EDX) analysis. The ultraviolet-diffuse reflectance spectroscopy (UV-DRS) spectra suggest a decrease in the band gap energy of to 2.335 eV, promoting a higher degree of visible light harvesting. Upon optimization, by varying the pH, the amount of the photocatalyst, and the concentration of Cr(IV), exhibits the highest photocatalytic efficiency (96.39%) while using a Cr(VI) concentration of 10 ppm at pH 2 and 15 mg of the photocatalyst, and the photoreduction of Cr(VI) to Cr(III) follows the pseudo-first-order reaction. The decrease in the PL intensity in reveals a faster transfer of electrons from to . Further, the higher degree of band bending at the / heterojunction, revealed from the Mott-Schottky analysis, facilitates efficient charge transfer and eventually faster and efficient photoreduction of Cr(VI) to Cr(III). The reusability and stability test undertaken for reveals that even after five cycles, the Cr (VI) photoreduction efficacy is retained. This work provides insights into photoreduction of Cr (VI) by using such heterostructures.
通过水热法合成了具有协同助催化剂修饰的异质结构光催化剂，其具有不同的负载浓度，以有效驱动六价铬还原。通过对应单斜相的X射线衍射（XRD）峰的出现以及拉曼光谱中对应于四面体VO的反对称（834 cm）和对称拉伸（715 cm）以及D（1330 cm）和G（1570 cm）带，证实了异质结构光催化剂的形成。场发射扫描电子显微镜（FESEM）显示，纳米晶体的蠕虫状结构生长在的层状薄片上，对于而言，其表面积增加到15.62 mg。X射线光电子能谱（XPS）分析证实了V和Ti态的存在，能量色散X射线（EDX）分析表明纳米晶体在的层状薄片上均匀分布。紫外漫反射光谱（UV-DRS）光谱表明的带隙能量降低至2.335 eV，促进了更高程度的可见光捕获。经过优化，通过改变pH值、光催化剂的量和Cr(IV)的浓度，在pH为2、使用15 mg光催化剂且Cr(VI)浓度为10 ppm时，表现出最高的光催化效率（96.39%），并且Cr(VI)到Cr(III)的光还原遵循准一级反应。中PL强度的降低表明电子从到的转移更快。此外，莫特-肖特基分析显示的/异质结处更高程度的能带弯曲促进了有效的电荷转移，并最终使Cr(VI)更快、更有效地光还原为Cr(III)。对进行的可重复使用性和稳定性测试表明，即使经过五个循环，Cr(VI)光还原效率仍得以保留。这项工作为使用此类异质结构进行Cr(VI)的光还原提供了见解。
