Highly active photocatalytic coatings prepared by a low-temperature method

Area of Science:

• Materials Science
• Environmental Chemistry
• Chemical Engineering

Background:

• Titanium dioxide (TiO2) in anatase form exhibits valuable photocatalytic properties for water purification.
• Fixed-bed photocatalytic reactors are preferred over suspended ones to avoid catalyst filtration issues.
• Effective immobilization of TiO2 on substrates is critical to prevent leaching and ensure long-term performance.

Purpose of the Study:

• To evaluate the physical and photocatalytic properties of five commercial TiO2 photocatalysts and one pigment immobilized on glass slides.
• To determine the most effective immobilization method and photocatalyst for fixed-phase water purification applications.
• To assess the mechanical stability and photocatalytic activity under various UVA irradiation intensities.

Main Methods:

• Successful immobilization of TiO2 photocatalysts on glass slides using a "sol suspension" procedure.
• Mechanical tests and characterization methods (e.g., SEM, BET) were employed to assess layer stability and morphology.
• Photocatalytic activity was evaluated by detecting hydroxyterephthalic acid (HTPA), a fluorescent oxidation product of terephthalic acid (TPA), under UVA and UV-vis irradiation.

Main Results:

• Aeroxide® P90, when incorporated into a silica-titania binder, demonstrated the highest photocatalytic activity among all tested materials.
• The Aeroxide® P90 layer exhibited a significant increase in photocatalytic activity across the tested range of UVA irradiation intensities (2.3 mW/cm(2) to 6.1 mW/cm(2)).
• Several immobilized photocatalytic layers showed high mechanical stability, suitable for practical applications in water purification.

Conclusions:

• The "sol suspension" immobilization technique is effective for preparing stable and active TiO2 photocatalytic layers on glass slides.
• Aeroxide® P90 is a highly promising photocatalyst for fixed-bed water purification systems due to its superior activity and stability.
• The developed immobilized TiO2 layers hold potential for efficient and robust photocatalytic water treatment processes.