Hydrothermal Surface Engineering of Anodic WO₃ Photoelectrode by Simultaneous Iron Doping and Fe₃O₄/FeWO₄ Formation

Area of Science:

• Materials Science
• Electrochemistry
• Photocatalysis

Background:

• Tungsten oxide (WO3) is a promising semiconductor for photoelectrochemical water splitting.
• Improving the efficiency and stability of WO3-based photoanodes remains a key challenge.
• Surface modification strategies are crucial for optimizing semiconductor performance.

Purpose of the Study:

• To enhance the photoelectrochemical water oxidation performance of porous anodized WO3.
• To investigate the effects of iron (Fe) doping and hydrothermal surface modification.
• To explore the formation of Fe-containing phases and their impact on WO3 properties.

Main Methods:

• Hydrothermal surface modification of porous anodized WO3.
• Fe doping to create FeWO4 and Fe3O4 phases.
• Comprehensive characterization using XRD, FESEM, EDS, XPS, Raman, and UV-Vis DRS.
• Photoelectrochemical measurements including linear voltammetry, amperometry, and electrochemical impedance spectroscopy.

Main Results:

• Fe doping resulted in a two-fold increase in photocurrent compared to pure WO3.
• Enhanced long-term stability of the surface-engineered WO3 photoanodes.
• Improved visible light performance evidenced by a red shift in light absorption and increased IPCE.
• Formation of a heterojunction between WO3 and FeWO4, a p-type semiconductor.

Conclusions:

• Hydrothermal Fe doping effectively enhances WO3 photoanode performance for water oxidation.
• Oxygen vacancies and the WO3/FeWO4 heterojunction contribute to improved charge carrier dynamics.
• This approach offers a viable route for developing efficient and stable WO3-based photoelectrodes for solar fuel production.