Spatially Engineered Ternary Schottky/S-Scheme Heterojunctions for Artificial Photosynthesis

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Photocatalytic CO2 reduction is key for carbon mitigation and solar fuel production.
• Existing photocatalysts face challenges like inefficient charge separation and rapid recombination.
• Binary heterojunctions often struggle with timescale mismatches between charge transfer and surface reactions.

Purpose of the Study:

• To develop an advanced photocatalyst overcoming limitations of single-component and binary systems.
• To engineer a ternary heterostructure for efficient spatial charge separation and enhanced CO2 reduction.
• To investigate the underlying mechanisms of charge migration and surface reactions.

Main Methods:

• Fabrication of a spatially engineered Nb2C/Nb2O5/ZnO ternary heterostructure.
• Utilized in situ irradiated X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), and femtosecond transient absorption spectroscopy (fs-TAS).
• Investigated bidirectional interfacial electric fields (IEFs) and photothermal effects.

Main Results:

• The Nb2C/Nb2O5/ZnO structure established S-scheme and Schottky junctions with bidirectional IEFs.
• Demonstrated efficient and spatially resolved charge migration, suppressing Coulombic recombination and prolonging carrier lifetimes.
• Achieved high-efficiency CO2 photoreduction without molecular cocatalysts or sacrificial agents, enhanced by Nb2C's photothermal effect.

Conclusions:

• The engineered ternary heterostructure provides a mechanistically distinct approach for artificial photosynthesis.
• Spatial charge separation and synergistic effects are crucial for high-performance photocatalysis.
• This scalable method offers a promising route for sustainable solar fuel production and carbon utilization.