Photocatalytic oxidation of NO_x gases using TiO_2: a surface spectroscopic approach

摘要

The bandgap of solid-state TiO_2 (3.2 eV) enables it to be a useful photocatalyst in the ultraviolet (λ<380 nm) region of the spectrum. A clean TiO_2 surface in the presence of sunlight therefore enables the removal of harmful NO_x gases from the atmos- phere by oxidation to nitrates. These properties, in addition to the whiteness, relative cheapness and non-toxicity, make TiO_2 ideal for the many de-NOX catalysts that are currently being commercially exploited both in the UK and Japan for concrete paving materials in inner cities.