Self-Aligned BiFeO₃ Polarization Vector Induced by MnO₆ Octahedral Jahn-Teller Distortion for Enhanced Photocatalytic...

Area of Science:

• Materials Science
• Catalysis
• Solid-State Chemistry

Background:

• Designing high-performance ferroelectric photocatalysts is hindered by challenges in precisely controlling polarization vector alignment through chemical synthesis.
• Existing methods often require external electric fields, limiting practical applications.

Purpose of the Study:

• To introduce a chemical synthesis strategy that resolves polarization disorder in ferroelectric materials without external electric fields.
• To investigate the Jahn-Teller distortion-mediated mechanism for modulating polarization vector alignment.
• To enhance the photocatalytic performance for CO2 conversion.

Main Methods:

• Utilizing Jahn-Teller distortion by elongating MnO6 octahedra to induce coordinated atomic displacement.
• Modulating localized charge of Manganese (Mn) via redistribution with oxygen ligands to achieve an optimal electronic configuration (Mn t2g3eg1).
• Confirming the mechanism using X-ray absorption spectroscopy, Raman spectroscopy, and atomic pair distribution functions.

Main Results:

• The Jahn-Teller distortion drives displacement of Fe and O atoms along the [001̅] direction, intensifying FeO6 octahedra deformation and forming oriented polarization.
• This oriented polarization leads to rapid charge carrier separation due to the depolarization electric field.
• Achieved a CO2 to CO conversion yield of 30.51 μmol g-1 h-1, nearly five times that of the original BiFeO3.

Conclusions:

• The Jahn-Teller distortion-mediated mechanism offers an innovative strategy to modulate polarization vectors in ferroelectric materials.
• This approach provides insights into developing advanced ferroelectric photocatalysts by manipulating electronic structure.
• The enhanced photocatalytic activity demonstrates the potential of this method for sustainable chemical conversions.