Adsorption enhanced photocatalytic degradation of Rhodamine B using GdxBi1-xFeO3@SBA-15 (x=0, 0.05, 0.10, 0.15) nanocomposites under visible light irradiation

BiFeO3 nanomaterials have recently generated much interest due to their relatively narrow band gap energies (similar to 2.0-2.8 eV), their stability and low cost which leads to effective visible-light photocatalysts for water splitting and for the degradation of organic pollutants. Here, we show that very high removal efficiency of the organic dye Rhodamine B can be achieved using GdxBi1-xFeO3@SBA-15 nanocomposites (x = 0, 0.05. 0.10, 0.15) under visible light irradiation. Specifically, we study the photocatalytic degradation of Rodamine B using the above nanocomposite materials, with pore volume loadings of 5-25%, prepared by a wet-impregnation nanocasting technique with pre-fabricated metal tartarates, as metal precursors, and mesoporous silica SBA-15, as a host matrix. We find that the best removal performance is achieved by a 10 vol% Gd0.05Bi0.95FeO3@SBA-15 sample, shown by a complete dye degradation in approximately 3 h using very low concentrations of the actural active photocatalyst. The superior efficiencies of the nanocomposites, which outperformed their parent compounds, i.e. GdxBi1-xFeO3 nanoparticles as well as unfilled SBA-15, are attributable to a synergistic adsorption enhanced photocatalytic degradation process. The possible mechanism in the photodegradation process was investigated and discussed on the basis of trapping experiments.

Automated summary

BiFeO3 nanomaterials have attracted much interest as effective visible-light photocatalysts for water splitting and organic pollutant degradation due to their narrow band gap energies. The use of GdxBi1-xFeO3@SBA-15 nanocomposites can achieve high removal efficiency of the organic dye Rhodamine B, with the 10 vol% Gd0.05Bi0.95FeO3@SBA-15 sample showing the best performance. The synergistic adsorption enhanced photocatalytic degradation process contributes to the superior efficiencies of the nanocomposites over their parent compounds.