A Novel Metal-Free Visible-Light-Driven Photo catalytic Foam for Efficient Degradation of Methyl Orange

Abstract

Here, graphitic carbon nitride (g-C 3 N 4) was integrated with polyurethane foam (PUF) as a novel metal-free visible-light-driven photocatalytic foam (g-C 3 N 4 /PUF) by a facile ultrasonic method. The fabricated samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffractometry (XRD) and UV-Vis diffuse reflectance spectroscopy (UV-V is DRS). This composite foam exhibited enhanced photocatalytic performance compared to g-C 3 N 4 powders for degradation of methyl orange (MO) in water without stirring under visible light irradiation. The pseudo-first order rate constant (kobs) for MO photodegradation by g-C 3 N 4 /PUF increased by up to a factor of 4.5 when compared with that of g-C3N4. The optimal addition dosage of g-C 3 N 4 precursors for 1 cm 3 PUF was determined to be 0.5 g, namely g-C3N4/PUF-5. The new foam maintained its photocatalytic activity at least five consecutive cycles. Specially, the photocatalytic mechanism of g-C3N4/PUF was revealed, and superoxide radicals (•O 2-) were found to play a more dominant role than hydroxyl radicals (•OH) for organic pollutant degradation.