1D α-FeO(OH) and its transformation to α-Fe2O3 nanorods: Synthesis and photocatalytic evaluation using bromocresol green

• Microwave-assisted hydrothermal process was used to prepare α-FeO(OH) and α-Fe 2 O 3 . • Bundle-like 1D nanostructures with high crystallinity were obtained. • Photocatalysis activity was evaluated in the degradation of bromocresol green (BG). • Efficiency of about 88 and 81 % were recorded for the α-FeO(OH) and α-Fe 2 O 3 respectively. • Reusability studies confirm that both products can be reasonably reused up to the 3rd cycle. In this study, nanostructured α-FeO(OH) (goethite) have been successfully prepared via a microwave-assisted hydrothermal (MAH) process. The subsequent calcination in a furnace resulted in the formation of α-Fe 2 O 3 (hematite) nanorods. The transformation of the orthorhombic α-FeO(OH) to rhombohedral α-Fe 2 O 3 was confirmed by X-ray diffraction (XRD) analysis. Bundle-like α-FeO(OH) nanostructures were prepared, while crystalline rod-shaped α-Fe 2 O 3 were confirmed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The performance of these nanomaterials as photocatalysts was evaluated in the degradation of bromocresol green (BG) under visible light irradiation for 2 h; and the degradation percentage was found to be 88 and 81 % for the α-FeO(OH) and α-Fe 2 O 3 respectively. The effects of solution pH, catalyst’s dosage, and initial dye concentration were investigated. Results revealed that the removal of BG increased with an increase in both catalyst dosages. Reusability studies confirm that both products can be reasonably reused up to the 3rd cycle. Hence, this study suggests the robustness and stability of the α-FeO(OH) and Fe 2 O 3 catalysts which make them viable for reuse.