TiO₂-CeO₂/g-C₃N₄ S-scheme heterostructure composite for enhanced photo-degradation and hydrogen evolution performance...

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Developing efficient photocatalysts is crucial for environmental remediation and sustainable energy production.
• Graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) are promising semiconductor materials, but their photocatalytic efficiency can be limited.
• Cerium oxide (CeO2) nanoparticles can enhance the properties of composite materials.

Purpose of the Study:

• To synthesize and characterize novel g-C3N4/TiO2-CeO2 hybrid nanocomposites.
• To evaluate the photocatalytic performance of these nanocomposites for dye degradation and hydrogen evolution.
• To investigate the underlying charge separation mechanisms.

Main Methods:

• Fabrication of g-C3N4/TiO2-CeO2 nanocomposites using calcination and hydrothermal techniques.
• Comprehensive characterization including structural, morphological, elemental, and optical analysis.
• Photocatalytic activity testing for methylene blue (MB) degradation and hydrogen evolution reaction (HER) under visible light.
• Electrochemical studies including electrochemical impedance spectroscopy (EIS).
• Density functional theory (DFT) computation.

Main Results:

• The g-C3N4/TiO2-CeO2 nanocomposites exhibited significantly enhanced photocatalytic activity for MB degradation (approx. 97%) compared to pristine g-C3N4 and g-C3N4/TiO2 composites.
• The rate constant (k) for the hybrid nanocomposite was substantially higher than individual components and binary composites.
• Evidence suggests an S-scheme charge separation mechanism, leading to efficient separation of photo-excited electron-hole pairs.
• The nanocomposites demonstrated good performance in hydrogen evolution reactions.

Conclusions:

• The rational design of g-C3N4/TiO2-CeO2 nano-heterostructures is highly effective for enhancing photocatalytic efficiency.
• These hybrid nanocomposites show great potential as visible-light-driven recyclable photocatalysts for environmental purification.
• The synergistic effects and S-scheme mechanism contribute to the superior performance for degradation and hydrogen production.