  Supported carbon nanosheets and carbon nanotubes served as sacrificial
templates for preparing spacious TiO2 photocatalytic thin films. Amorphous TiO2
was deposited conformally on the carbonaceous template material by atomic layer
deposition (ALD). Upon calcination at 550{\deg}C, the carbon template was
oxidatively removed and the as-deposited continuous amorphous TiO2 layers
transformed into interlinked anatase nanoparticles with an overall morphology
commensurate to the original template structure. The effect of type of
template, number of ALD cycles and gas residence time of pollutant on the
photocatalytic activity, as well as the stability of the photocatalytic
performance of these thin films was investigated. The TiO2 films exhibited
excellent photocatalytic activity towards photocatalytic degradation of
acetaldehyde in air as a model reaction for photocatalytic indoor air pollution
abatement. Optimized films outperformed a reference film of commercial PC500.
