Visible light responsive mesoporous graphene–Eu2O3/TiO2 nanocomposites for the efficient photocatalytic degradation of 4-chlorophenol

Abstract

Mesoporous graphene–Eu₂O₃/TiO₂ nanocomposites with different weight percentages were synthesized by hydrothermal method using Pluronic P123 as the structure directing template. The synthesized materials were characterized by XRD, HRTEM, SEM-EDAX, N₂ adsorption–desorption studies, XPS, UV-vis DRS, FT-IR and photoluminescence spectroscopy. The photocatalytic activity of the catalysts for the degradation of 4-chlorophenol, a model pollutant was evaluated under visible light irradiation. 0.7 wt% GR–Eu₂O₃/TiO₂ nanocomposites showed higher efficiency under visible light among the synthesized materials due to high surface area with narrow band gap and effectively suppressed electron–hole recombination. UV-Vis DRS showed the shift in the light absorption band-edge position to visible region for GR–Eu₂O₃/TiO₂ nanocomposites. The well reduced photoluminescence intensity revealed the effective charge separation for GR–Eu₂O₃/TiO₂ nanocomposites than GR–TiO₂, Eu₂O₃-TiO₂ and bare meso TiO₂. Eu³⁺ ions were trapping and transferring the exited electrons to graphene layer and adsorbed oxygen efficiently, hence the co-doping of europium and graphene synergistically suppressed the electron–hole recombination. The suppressed electron–hole recombination enhanced ˙OH radicals formation and subsequently the photocatalytic degradation of 4-chlorophenol.