Unlocking a Type-II CoO@BiVO₄ Heterostructure for Wastewater Purification

Area of Science:

• Materials Science
• Environmental Science
• Electrochemistry

Background:

• Photoelectrocatalytic (PEC) degradation of refractory organic pollutants is vital for water purification.
• Semiconductor-based heterostructure photoanodes offer potential but face challenges like electron/hole recombination and slow charge transfer.
• Developing efficient and stable photoanodes is crucial for advanced oxidation processes.

Purpose of the Study:

• To develop a novel semiconductor-based heterostructure photoanode for enhanced PEC efficiency.
• To investigate the PEC performance of CoO@BiVO4 nanowire array films for degrading organic pollutants.
• To understand the underlying mechanisms responsible for improved PEC activity.

Main Methods:

• Fabrication of a Ti/CoO@BiVO4 nanowire array film using a straightforward hydrothermal method.
• Characterization of the electrode's structural, morphological, and electrochemical properties.
• Evaluation of PEC decolorization efficiency using active brilliant blue KN-R and assessment of long-term stability.

Main Results:

• The optimized Ti/CoO@BiVO4 electrode demonstrated excellent PEC decolorization efficiency (∼92.8%) for active brilliant blue KN-R.
• The electrode exhibited superior long-term stability compared to previous reports.
• Enhanced PEC performance was attributed to a large electrochemical active area, low charge transfer resistance, and a negative flat band potential.
• A type-II heterostructure formed between CoO and BiVO4, promoting electron/hole pair generation and separation.

Conclusions:

• The developed Ti/CoO@BiVO4 photoanode shows significant potential for efficient water PEC degradation of organic pollutants.
• The n-type semiconductor heterostructure effectively suppresses charge recombination and enhances charge transfer.
• The material offers a promising solution for water treatment with a superior service life.