Photocatalytic activity of WO3/Fe2O3 nanocomposite photoanode

• Nanocomposite WO3/Fe2O3 materials have successfully been synthesized.
• The morphology of nanocomposites were distinguishingly altered.
• The nanocomposites exhibited higher activity compare to pristine WO3 and Fe2O3.
• (WO3)0.75–(Fe2O3)0.25 revealed the highest photocatalytic activity.

The (WO3)1−x–(Fe2O3)x (0 ≤ x ≤ 1) nano-particle thin films with various compositions have been deposited onto the fluorine thin oxide (FTO) coated glass substrate using sol-gel, spin-coating technique. An electrode/electrolyte interface has been formed between an n-type (WO3)1−x–(Fe2O3)x composite semiconductor and a 0.5 mol L−1 Na2SO4 aqueous solution. The photo-catalytic activity of the films has been investigated through the photocurrent-voltage. UV-visible spectroscopy, SEM and XRD have been used to characterize solar absorption, surface morphology and the crystallinity of samples, respectively. The photo-electrochemical (PEC) experiments were performed under solar irradiation to evaluate the amount of electron-hole generation in different samples. All the composite nano-particles indicated higher efficiency compared to pristine iron and tungsten oxides. A clear relationship was also confirmed between band gap energy and photo-catalytic activity of thin films. The band-gap energy of mixed thin films decreased linearly with the increasing Fe2O3 content in the film samples. The maximum photocurrent density of 2.34 mA cm−2 has been obtained for sample with x = 0.25 at 1.4 V vs. RHE. The result revealed that the sample also has the highest photon-to-current efficiency (0.87%), and solar absorption.