Synthesis of sol–gel derived holmium aluminium garnet on exfoliated g-C3N4: a novel visible-light-driven Z-scheme photocatalyst for the degradation of sunset yellow FCF

Abstract

The synthesis of harmless, cost-effective, and visible-light-driven photocatalytic materials has received significant attention to the researchers in the environmental decontamination applications. In this perception, we report the synthesis of a novel hybrid photocatalyst using holmium aluminium garnet nanostructures modified graphitic carbon nitride (HoAG/g-C3N4) for the first time. A facile sol–gel route and thermal polycondensation methods have been used for the photocatalyst preparation. Different physicochemical characterization methods were employed to confirm the structural, chemical, optical, and morphological properties of the HoAG/g-C3N4 photocatalyst. The visible light absorption enhancement of HoAG/g-C3N4 nanocomposites is due to the broad absorption of trivalent ion (Ho3+) and thus proves to be a promising candidate for the visible-light-driven photocatalysis. The HoAG5/g-C3N4 nanocomposite shows 90.66% removal of sunset yellow FCF dye within 60 min under visible-light irradiation. Also, the catalytic activity of the HoAG5/g-C3N4 nanocomposite was 1.28, and 3.13 times greater than that of pristine g-C3N4 and HoAG, respectively. The photocatalytic degradation of dye on HoAG/g-C3N4 hierarchical structure followed direct Z-scheme mechanism. Photoelectrochemical and recycling measurements show the higher photogenerated charge transfer efficiencies and stability of the HoAG/g-C3N4 nanocomposites.