Bifunctional PDDA-stabilized β-Fe2O3 nanoclusters for improved photoelectrocatalytic and magnetic field enhanced photocatalytic applications

Abstract

Photocatalytic water splitting for hydrogen production and water pollutant degradation is a frontier topic to solve energy and environmental problems. In particular, applying electric and magnetic fields on photocatalysts is the most promising solution to improve their catalytic activity. In this work, bifunctional catalyst PDDA-coated β-Fe₂O₃ nanoclusters (β-Fe₂O₃@PDDA) have been successfully synthesized by a simple one-pot method at 200 °C. β-Fe₂O₃@PDDA exhibits excellent photoelectrocatalytic (PEC) activity for the oxygen evolution reaction (OER) with an overpotential of 300 mV, Tafel slope of 45 mV dec⁻¹ and good catalytic stability. Moreover, β-Fe₂O₃@PDDA exhibited a good magnetic field-enhanced photocatalytic (MF-PC) RhB degradation activity under artificial simulated sunlight; the photocatalytic efficiency can be improved by 44% under an external magnetic field than that without a magnetic field. The surface PDDA-coated β-Fe₂O₃ can be stably dispersed in water for more than 10 days without agglomeration, which is of great significance for the MF-PC degradation of water pollutants in practical applications. The high catalytic activity for MF-PC is attributed to the magnetic field-suppressed electron–hole recombination and the spin-polarized properties of β-Fe₂O₃ in photocatalysis. Our study provides a new strategy for the preparation of highly dispersed β-Fe₂O₃ nanoclusters under mild conditions and the development of ultrastable organic/inorganic composite photocatalysts. This opens up a new avenue for developing electric and magnetic field-enhanced photocatalysts for use in clean energy and environmental control.