Investigation of photoelectrocatalytic degradation mechanism of methylene blue by α-Fe2O3 nanorods array

• Published in: Chinese journal of chemical engineering Vol. 57; no. 5; pp. 162 - 172
• Main Authors: Liu, Yaqiao, Hu, Shuozhen, Zhang, Xinsheng, Sun, Shigang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2023; State Key Laboratory of Chemical Engineering,School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China%State Key Laboratory of Physical Chemistry of Solid Surfaces,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China
• Subjects: Free radicals; Methylene blue; Photo-generated holes; Photoelectrocatalytic degradation mechanism; α-Fe2O3 nanorods array; Free radicals; Photoelectrocatalytic degradation mechanism; α-Fe2O3 nanorods array; Photo-generated holes; Methylene blue; Photoelectrocatalytic degradation; mechanism
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/j.cjche.2022.08.021

[Display omitted] Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge. Herein, vertically oriented mesoporous α-Fe2O3 nanorods array (α-Fe2O3-NA) is directly grown on fluorine-doped tin oxide (FTO) glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater. The Ov sites on the α-Fe2O3-NA surface are the active sites for methylene blue (MB) adsorption. Electrons transfer from the adsorbed MB to Fe-O is detected. Compared with electrocatalytic and photocatalytic degradation processes, the photoelectrocatalytic (PEC) process exhibited the best degrading performance and the largest kinetic constant. Hydroxyl, superoxide free radicals, and photo-generated holes play a jointly leading role in the PEC degradation. A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis. This work demonstrates that photoelectrocatalysis by α-Fe2O3-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation. The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.