Morphology controlled synthesis of α-Fe2O3-x with benzimidazole-modified Fe-MOFs for enhanced photo-Fenton-like catalysis

By Wenkai Xu, Wenjuan Xue, Hongliang Huang, Jiansong Wang, Chongli Zhong, Donghai Mei. 2021

154 citations recorded by the source corpus.

Abstract Intrinsically poor reactivity restricts pure hematite (α-Fe2O3) from practical photo-Fenton-like systems. Surface structure engineering is considered one of effective methods to tune its photo-Fenton-like catalytic performance. Therefore, it is essential to understand how the surface structure of α-Fe2O3-based photocatalysts alters its catalytic activity at the nanoscale. Herein, four α-Fe2O3-x materials with different morphologies (sphere, octahedron, spindle and rod) and controllable oxygen vacancies (OVs) were synthesized with benzimidazole (BIm)-modified Fe-MOFs (MOFs = metal-organic frameworks) as templates using the solvothermal method. The rod-like α-Fe2O3-x was found to exhibit the highest activity for the complete methylene blue (MB) degradation with apparent reaction rate constant k = 0.08 min−1. While apparent reaction rate constants for α-Fe2O3-x with sphere-, octahedron- and spindle-like morphologies are only 0.02, 0.035 and 0.05 min−1, respectively. The enhanced photocatalytic activity can be attributed to the synergy of large surface area, high Fe2+ and OVs concentrations. This is further substantiated by density functional theory (DFT) calculations, which indicates that both Fe2+ and OVs facilitate H2O2 dissociation to produce hydroxyl radicals (·OH) for MB degradation. The present work provides a promising strategy for designing low-cost and efficient α-Fe2O3-based photocatalysts with abundant OVs for photo-Fenton-like catalysis and other energy and environmental applications.

Subfields: Renewable Energy, Sustainability and the Environment, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/73d9bc0323b02965502fe698ab6f82a59c784707