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

摘要

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, N-2 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.