Morphology/facet-dependent photo-Fenton-like degradation of pharmaceuticals and personal care products over hematite nanocrystals

Abstract

• α-Fe 2 O 3 of cuboid/rhombohedral, spheroidal, rice-like, and plate-like were synthesised. • Photo-Fenton-like degradation of p-hydroxybenzoic acid (p-HBA) and sulfachloropyridazine (SCP) was conducted. • Correlation among atomic configuration of the exposed facets, specific surface area and photocatalytic activity was established. • Degradation mechanism and pathways for p-HBA and SCP were proposed. Hematite (α-Fe 2 O 3 ) with different shapes and preferentially exposed facets may differ in surface energy and atomic configuration resulting in versatile catalysis. Herein, four morphologies of α-Fe 2 O 3 nanocrystals, e.g. cuboid/rhombohedral, spheroid, rice-like, and plate-like are synthesised by hydrothermal/solvothermal routes. The correlation between morphology and photochemical performance is established by investigating the photo-Fenton-like degradation of p-hydroxybenzoic acid (p-HBA) and sulfachloropyridazine (SCP). The plate-like sample demonstrates the highest removal efficiency, whereas the normalised reaction rate by specific surface area shows the reaction order as cuboid/rhombohedral > plate-like > spheroid > rice-like. This can be ascribed to the synergistic role of the surface atomic arrangement and specific surface area. The main reactive species and degradation pathways were studied in detail. The research findings may offer new insights into the morphology/facet-dependent photochemical remediation of emerging contaminants (ECs) on α-Fe 2 O 3 .