Surface Fermi Level Modulation of Photoanode by Optimized Conducting Nanoparticle Heterointerfaces for Enhanced...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Photoelectrochemical (PEC) water splitting utilizes semiconductor electrodes coated with conducting nanoparticles to enhance performance.
• However, PEC activity is often inconsistent due to factors like defect concentration, nanoparticle choice, and surface coverage.

Purpose of the Study:

• To investigate the rational positioning and optimal coverage of metallic nickel phosphide (Ni₂P) nanospheres on bismuth vanadate (BVO) electrodes.
• To enhance the PEC oxygen evolution reaction (OER) performance of BVO electrodes.

Main Methods:

• Multi-scale (MS) simulation to predict optimal heterointerface contact coverage.
• Experimental synthesis and characterization of Ni₂P nanosphere-deposited BVO electrodes.
• Density functional theory (DFT) calculations and analytic modeling to understand interfacial effects.

Main Results:

• MS simulation predicted an optimal Ni₂P coverage range of 6%-11% on BVO for high PEC OER.
• Experimental results showed a Ni₂P/BVO electrode with 9.4% Ni₂P coverage achieved significantly enhanced photocurrent density.
• The optimal coverage improved PEC OER performance despite Ni₂P's inherently poor OER kinetics.

Conclusions:

• Rational positioning and optimal coverage of Ni₂P nanospheres on BVO electrodes drastically improve PEC OER.
• Surface coverage of Ni₂P nanospheres modulates the BVO Fermi level, tailoring OER surface reaction kinetics.
• This study presents a novel design strategy for nanoparticle-deposited photoelectrodes for advanced PEC applications.