Pt colloidal accommodated into mesoporous TiO2 films for photooxidation of acetaldehyde in gas phase

Abstract

Colloidal platinum nanoparticles were introduced into the mesoporous TiO2 multi-layers deposited on soda-lime glass. The synthesized photocatalysts colloidal Pt loaded-TiO2 films were evaluated for their photocatalytic activity for acetaldehyde oxidation in gas phase and compared with the commercial Pilkington Glass ActivTM. Isotherms of adsorption of Kr on all the films are of type IV characterized by a broad hysteresis loop, which proves the presence of mesopores within the films. The thickness of the first-layer TiO2 film was measured ∼225nm which increased to 1120nm at five-layers TiO2. XPS measurements showed very small shoulder Pt 4f7/2 and 4f5/2 binding energy are 71.85 and 74.12eV and 4d5/2 binding energy at 315.4 and 331.64eV, which suggests that the Pt is in a metallic state. TEM and SEM images show that TiO2 films are random worm-like network and Both, the HRTEM image and the selective area electron diffraction show well resolved (101) lattice fringes (distance: 0.352nm) indicative of a crystalline TiO2 anatase framework. The particle size of these TiO2 nanocrystals are 8±2nm. It was found that the worm-like network TiO2 is more photoactive than either nonporous TiO2 or Pilkington Glass ActivTM and its photonic efficiency is higher 3 and 6 times respectively. Also, addition of colloidal Pt enhanced the photonic efficiency of mesoporous TiO2 by ∼two times for all different TiO2 layers. The 3-D cubic mesoporous TiO2 is stable and can be recycled without loss of the photochemical activity up to five-times.