Photoreduction of CO2 to CH4 over Efficient Z-Scheme $\gamma$-Fe2O3/g-C3N4 Composites

Abstract

A series of composite γ-Fe2O3/g-C3N4 (denoted as xFeCN with x equal 5, 10, 15, and 20 of γ-Fe2O3 percentage in weight) was prepared by calcination and precipitation-impregnation methods. X-ray diffraction (XRD), Fourier transform infrared (FTIR), and X-ray photoelectron spectrometry (XPS) characterizations indicated the successful synthesis of Z-scheme FeCN composites. A red shift of the light absorption region was revealed by UV-vis diffuse reflectance spectroscopy (UV-DRS). In addition, photoluminescence spectroscopy (PL) spectra showed an interface interaction of two phases Fe2O3 and g-C3N4 in the synthesized composites that improved the charge transfer capacity. The photocatalytic activity of these materials was studied in the photoreduction of CO2 with H2O as the reductant in the gaseous phase. The composites exhibited excellent photoactivity compared to undoped g-C3N4. The CH4 production rate over 10FeCN and 15FeCN composites (2.8 × 10−2 and 2.9 × 10−2 μmol h−1 g−1, respectively) was ca. 7 times higher than that over pristine g-C3N4 (0.4 × 10−2 μmol h−1 g−1). This outstanding photocatalytic property of these composites was explained by the light absorption expansion and the prevention of photogenerated electron-hole pairs recombination due to its Z-scheme structure.

Photocatalytic Dye Degradation and Bio-Insights of Honey-Produced α-Fe2O3 Nanoparticles

“…The oxygen attachment on the Fe increased the surface area and reduced electron trapping. Lattice oxygen peaks were present at 531, and 15 eV represents the O-1s state which formed the Fe-O bonding and confirmed the FN nanoparticles of α-Fe 2 O 3 [46]. The carbon peak for the FNH nanoparticles was obtained from the 284.75 eV and 288.97 eV binding energies, representing C-O and C=O at the O-1s state.…”

Ag/GO/Fe3O4/γ-Fe2O3 Nanocomposite for Green-Light-Driven Photocatalytic Oxidation of 5-Hydroxymethylfurfural to 5-Hydroxymethyl-2-furancarboxylic Acid

“…The values of X for different materials are as follows: GO has a value of 6.09 eV, Fe 3 O 4 has a value of 5.78 eV, and γ-Fe 2 O 3 has a value of 5.825 eV …”

“…Fe 3 O 4 has a value of 5.78 eV,61 and γ-Fe O 3 has a value of eV 62. E e represents the energy of free electrons on the hydrogen scale, which is approximately 4.5 eV 60.…”