Tuning surface hydrophilicity of a BiVO₄ photoanode through interface engineering for efficient PEC water splitting

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Photoelectrochemical (PEC) water splitting is a promising technology for renewable hydrogen production.
• Improving the efficiency and stability of photoanodes is crucial for practical PEC applications.
• Bismuth vanadate (BVO) is a well-studied photoanode material, but its performance can be further enhanced.

Purpose of the Study:

• To enhance photoelectrochemical (PEC) water oxidation performance by integrating cobalt phthalocyanine (CoPc) with bismuth vanadate (BVO).
• To investigate the effect of interfacial engineering and hydrophilicity modification on BVO-based photoanodes.
• To develop a more efficient and stable photoanode for PEC water splitting.

Main Methods:

• A direct solvothermal method was employed to synthesize the BVO@CoPc composite photoanode.
• Characterization of the photoanode's structure, morphology, and electrochemical properties.
• Evaluation of PEC performance, including photocurrent density and incident photon-to-current conversion efficiency (IPCE).

Main Results:

• The BVO@CoPc photoanode achieved a photocurrent density of 4.0 mA cm⁻² at 1.23 V vs. RHE, a 3.1-fold increase compared to unmodified BVO.
• Superior stability and an impressive IPCE of 81% were observed for the BVO@CoPc photoanode.
• The solvothermal method resulted in enhanced interfacial contact and surface hydrophilicity, improving charge carrier transfer and separation.

Conclusions:

• Interfacial engineering and hydrophilicity modification of BVO with CoPc significantly enhance PEC water oxidation.
• The developed BVO@CoPc photoanode offers a promising pathway towards more efficient and durable PEC water splitting systems.
• The solvothermal synthesis approach provides a superior method for fabricating high-performance composite photoanodes.