Superior Adsorption and Photocatalytic Degradation Capability of Mesoporous LaFeO3/g-C3N4 for Removal of Oxytetracycline

Abstract

Mesoporous LaFeO3/g-C3N4 Z-scheme heterojunctions (LFC) were synthesized via the incorporation of LaFeO3 nanoparticles and porous g-C3N4 ultrathin nanosheets. The as prepared LFC were characterized by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, powder X-ray diffraction, Raman spectra and N2 adsorption analysis. The structural analysis indicated that the reheating process and the addition of NH4Cl in the thermal polymerization were the key factors to get porous g-C3N4 ultrathin nanosheets and to obtain high specific surface areas of LFC. It remarkably enhanced the adsorption capacity and photocatalytic degradation of LFC for removal of oxytetracycline (OTC). The effect of the mass percentage of LaFeO3 in LFC, pH and temperature on the OTC adsorption was investigated. The LaFeO3/g-C3N4 heterojunction with 2 wt % LaFeO3 (2-LFC) exhibited highest saturated adsorption capacity (101.67 mg g−1) and largest photocatalytic degradation rate constant (1.35 L g−1 min−1), which was about 9 and 5 times higher than that of bulk g-C3N4 (CN), respectively. This work provided a facile method to prepare mesoporous LaFeO3/g-C3N4 heterojunctions with especially well adsorption and photocatalytic activities for OTC, which can facilitate its practical applications in pollution control.

Effective Removal of Methylene Blue on EuVO4/g-C3N4 Mesoporous Nanosheets via Coupling Adsorption and Photocatalysis

“…The BJH pore size distribution curves of CN, EVC-2, and EVC-5 are depicted in Figure 4 b, indicating the remarkable increase of EVC-2 and EVC-5 in the range of 1–50 nm. This might be caused by thermal etching in the reheating process, which is similar to the previous reported results [ 25 ]. The ultrathin layered structures increased the specific surface area of EVC-2, which is confirmed by the TEM and AFM results in Figure 1 .…”

“…This could be attributed to the limited dosage of EV in the heterojunctions. The small amount of EF could not be enough to change the chemical skeleton and bulk structure of CN, which is consistent with the results reported in the literature [ 25 , 26 ]. An adsorption band appearing between 2000 and 600 cm −1 was displayed in the FTIR spectra of CN, EVC-2, and EVC-5 ( Figure 3 b).…”

“…It reveals the existence of C, N, Eu, V, and O in EVC-2 and EVC-5. The O1s peak intensity of CN reduced with the increase of EV dosage, as reported previously, indicating more H 2 O being absorbed on CN [ 25 , 27 ]. In the C1s high-resolution XPS spectra of CN, EVC-2, and EVC-5, two peaks at 284.8 and 288.3 eV for CN were observed.…”

“…The BET specific surface areas (S BET ) and mesoporous structures of CN, EVC-2, EVC-5, EVC-10, and EVC-20 were assessed by the N 2 adsorption–desorption isotherms and the corresponding BJH pore size distribution curves. All catalysts presented type IV isotherms ( Figure 4 a), which indicated the mesoporous structures of these catalysts [ 6 , 25 , 34 ]. The H3 hysteresis loop at high P/P 0 from 0.50 to 1.00 suggested that the mesopores of the samples were irregular.…”

Perovskite Oxide Based Materials for Energy and Environment-Oriented Photocatalysis

“…In addition to BiFeO 3 , LaFeO 3 is also well studied for photocatalytic pollutant removal reactions. − The band gap of LaFeO 3 (about 2.1 eV) lies in the visible region and different nanostructures such as nanoparticles, ,,, nanospheres, , nanorods, nanotubes, and nanosheets have been prepared by researchers and used for the photocatalytic degradation of different organic pollutants (MB, RhB, methylphenol, and 4-chlorophenol (4-CP)). To further enhance the photocatalytic activity of LaFeO 3 , doping with other elements and coupling with other materials have also been reported. − ,− The other perovskites from this class, LnFeO 3 (Ln = Pr and Y) and SrFeO 3 are also reported for visible-light-assisted degradation of organic pollutants. − For example, Liang et al have synthesized the LaFeO 3 /g-C 3 N 4 p–n heterojunction photocatalyst by a solvothermal method using presynthesized components .…”