Synthesis and characterization of Z-scheme α-Fe2O3 NTs/ruptured tubular g-C3N4 for enhanced photoelectrochemical water oxidation

A composite of tubular g-C3N4 with alpha-Fe2O3 has been synthesized to improve the photocatalytic performance of tubular g-C3N4 by the formation of a Z-scheme heterostructure. The composites were fabricated by the combination of varying amounts of hydrothermally synthesized alpha-Fe2O3 nanotubes (NTs) and protonated ruptured tubular (RT) g-C3N4, by the electrostatic self-assembly method. The obtained composites were characterized by zeta potential, powdered-X-ray diffraction (p-XRD), scanning/transmission electron microscopy (S/TEM), photoluminescence (PL), and Fourier transform infrared spectroscopy (FTIR). PL and photocurrent measurements indicates a higher charge separation of the photo-generated electron-hole pair for Fe2O3 NTs/RT g-C3N4 composite with higher concentration of alpha-Fe2O3 NTs. UV-Vis diffuse reflectance spectroscopy (UV-Vis/DRS) shows the band gaps of pristine alpha-Fe2O3 NTs and RT g-C3N4 to be 1.86 eV and 2.72 eV respectively, while the band structures were determined by Mott-Schottky measurements. I-V curves obtained from photoelectrochemical water splitting shows that the formation of the composite decreased the oxidation overpotential as compared to pristine alpha-Fe2O3 NTs and pristine RT g-C3N4. Bode plots showed that the composite was able to increase the lifetime of the photo-generated electrons as compared to both RT g-C3N4 and alpha-Fe2O3 NTs.