Three‐Dimensionally Ordered Macroporous Titania with Structural and Photonic Effects for Enhanced Photocatalytic Efficiency

Abstract

The three dimensional photonic crystals concept has been employed for photocatalysis. Slow photons observed in photonic crystal structures will enhance the absorption of materials when the photon energy matches the absorbance of the materials, which would improve the photocatalytic efficiency. In this work, three dimensionally ordered macroporous (3DOM) titania was prepared by applying the colloidal templating method with a range of pore diameters. Calcination at different temperatures to remove the templates resulted in different crystalline phases. The structural and photonic properties were characterized and their effects on photocatalytic activity are presented as well. A strong effect of the pore diameter on the photocatalytic activity was observed and correlated with the photon energy involved in the photodegradation process of organics. A very interesting phenomenon was also observed: the sample prepared by using PS spheres of 250 nm had a high photocatalytic efficiency, which mismatched the effect of pore diameter, probably owing to the slow photon effect.

Slow Photons for Photocatalysis and Photovoltaics

“…In general, the red‐edge slow photons are believed to have relatively more practical applications as light intensity, in this case, is mainly localized in the high RI regions of the PC structure (e.g., the skeleton of an inverse opal) as revealed in photocatalysis and photovoltaic devices . Most recently, Deparis and Su demonstrated, through rigorous couple wave analysis simulations of light intensity distribution in inverse opals, that the blue‐edge slow photons are also able to enhance light harvesting.…”

Fabrication of inverse opal TiO2-supported Au@CdS core–shell nanoparticles for efficient photocatalytic CO2 conversion

“…Photonic crystals have periodic modulations of the refractive index on the length scale of the light wavelength, thus forbidding certain wavelengths of light to propagate through the materials and resulting in a stop-band reflection because of coherent Bragg diffraction. [19] The stop-band reflection frequencies depend on the periodicity and dielectric contrast of the photonic crystal. Slow photons effect appearing in photonic structures could increase the path length of the light, as the group velocity of light at the edge of these wavelengths decreases dramatically.…”

Binder-Free TiO2 Monolith-Packed Pipette Tips for the Enrichment of Phosphorylated Peptides

“…The pore size of the monolith (400 nm) is smaller than the template size (710 nm) owing to the shrinkage of the packed macrostructure during the calcination process. [21] To identify the crystalline structure of calcined TiO 2 monolith, the X-ray diffraction (XRD) pattern was recorded. From the XRD pattern shown in Fig.…”

“…The Brunauer-Emmett-Teller (BET) surface area and pore volume were measured to be 22 m 2 g À1 and 0.09 cm 3 g À1 , which are consistent with a previous report using polystyrene spheres as hard templates to synthesize TiO 2 with a similar pore size. [21] Thirty T-tips were prepared and weighted. The average amount of TiO 2 monolith in each T-tip was measured to be 0.150 AE 0.020 mg, indicating that the TiO 2 monolith amount in each packed T-tip is comparable.…”