Double-Hole-Mediated Codoping on KNbO₃ for Visible Light Photocatalysis

Area of Science:

• Materials Science
• Photocatalysis
• Computational Chemistry

Background:

• Cubic potassium niobate (KNbO3) is a promising photocatalyst.
• Improving its efficiency for applications like water splitting requires advanced doping strategies.

Purpose of the Study:

• To investigate the double-hole-mediated codoping strategy for enhancing the photocatalytic activity of cubic KNbO3.
• To theoretically assess various codoping combinations for optimizing bandgaps and electronic properties.

Main Methods:

• Theoretical study employing density functional theory (DFT) calculations.
• Analysis of dopant-dopant and dopant-oxygen coupling effects.
• Evaluation of bandgap reduction, impurity states, and band edge positions.

Main Results:

• Double-hole-mediated codoping significantly reduces effective bandgaps by eliminating unfavorable acceptor states.
• Cationic-anionic codoping (e.g., V-C, Ti-P) narrows bandgaps without introducing detrimental localized states.
• Specific codoped systems (N-N, C-S) show potential for Z-scheme photocatalysis, while V, S, and V-C codoping are promising for visible light water splitting.

Conclusions:

• The double-hole-mediated codoping strategy is effective in enhancing the photocatalytic performance of cubic KNbO3.
• Careful selection of dopants is crucial to avoid electron-hole recombination centers and ensure favorable band edge alignment for water splitting.
• Optimized codoped KNbO3 materials demonstrate enhanced visible light absorption and potential for efficient solar fuel production.