Ti-Modified Imogolite Nanotubes as Promising Photocatalyst 1D Nanostructures for H₂ Production

Area of Science:

• Materials Science
• Nanotechnology
• Photocatalysis

Background:

• Imogolite nanotubes (INTs) possess unique 1D structures with potential for charge separation.
• Large band gaps of pristine INTs limit their application in photocatalysis.
• Reducing the band gap is crucial for harnessing INTs' photocatalytic properties.

Purpose of the Study:

• To modify aluminogermanate INTs by incorporating titanium (Ti) to reduce their band gap.
• To investigate the effect of Ti incorporation on structural, optical, and photocatalytic properties.
• To evaluate the potential of Ti-modified INTs for hydrogen (H2) production.

Main Methods:

• Synthesis of double-walled aluminogermanate INTs with varying Ti precursor ratios (x = [Ti]/([Ge]+[Ti])).
• Characterization of structural and optical properties using various analytical techniques.
• Evaluation of photocatalytic performance for H2 production under illumination.

Main Results:

• Limited incorporation of Ti into INT walls was achieved.
• Optimal Ti incorporation (x ≈ 0.4) resulted in a significant increase in H2 production (≈1500 µmol g⁻¹ in 5 h).
• Enhanced photocatalytic activity correlated with a reduced recombination rate of photogenerated charge carriers.

Conclusions:

• Titanium modification effectively reduces the band gap of imogolite nanotubes, enhancing their photocatalytic performance.
• Noble metal-free Ti-modified INTs demonstrate superior H2 production capabilities compared to commercial TiO2-P25.
• These findings validate the potential of modified INTs as photoactive nanoreactors for energy applications.