Constructing Surface Plasmon Resonance on Bi₂WO₆ to Boost High-Selective CO₂ Reduction for Methane

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Localized surface plasmon resonance (LSPR) is crucial for advanced photocatalytic applications.
• Developing nonmetallic plasmonic materials with tunable LSPR remains a significant challenge.
• Bismuth Tungstate (Bi2WO6) is a promising semiconductor photocatalyst.

Purpose of the Study:

• To construct plasmonic Bi2WO6 via electron doping to induce LSPR.
• To investigate the role of oxygen vacancies (V1 and V2) in LSPR and photocatalysis.
• To demonstrate the enhanced performance of plasmonic Bi2WO6 in CO2 reduction to methane.

Main Methods:

• Electron doping to create oxygen vacancies in Bi2WO6.
• Density Functional Theory (DFT) calculations to understand electronic structure and LSPR mechanism.
• Single-particle photoluminescence (PL) spectroscopy to study photoelectron trapping.
• CO2 reduction reaction (CO2-RR) experiments under UV-visible light irradiation.
• In situ Fourier transform infrared (FTIR) spectroscopy.

Main Results:

• Plasmonic Bi2WO6 with strong LSPR (500-1400 nm) was successfully synthesized through controlled electron doping.
• Oxygen vacancies at W-O-W sites (V1) were identified as key to inducing LSPR and facilitating photoelectron collection.
• Plasmonic Bi2WO6-V1 exhibited a 26-fold higher methane generation rate (9.95 μmol g⁻¹ h⁻¹) compared to Bi2WO6-V2 (0.37 μmol g⁻¹ h⁻¹) in CO2-RR.
• A 93% PL quenching efficiency confirmed effective photoelectron trapping at V1 sites.

Conclusions:

• Electron doping is an effective strategy to create nonmetallic plasmonic materials like Bi2WO6.
• The precisely controlled oxygen vacancies (V1) in Bi2WO6 are critical for achieving strong LSPR and high photocatalytic activity.
• Plasmonic Bi2WO6 demonstrates significant potential for selective methane production via CO2 reduction, driven by LSPR effects.