Facet- and defect-engineered Pt/Fe2O3 nanocomposite catalyst for catalytic oxidation of airborne formaldehyde under ambient conditions.

Formaldehyde (HCHO) is one of the most infamous indoor pollutants that imposes a great threat to human health. Herein, we report the development of a high-performance Pt/Fe2O3 catalyst for HCHO oxidation employing a facet- and defect-engineering strategy, with special focus on the surface structure effect of α-Fe2O3 on the catalytic properties. A supported Pt nanocatalyst on hollow octadecahedral α-Fe2O3 with exclusively exposed {113} and {104} facets was prepared using a hydrothermal method followed by impregnation-reduction treatment. The high-index facets of α-Fe2O3 render the formation of abundant oxygen vacancies and an improved dispersion of Pt nanoparticles. This led to an increased Pt/O-vacancy coexistence in close proximity, which collaboratively promote the generation of active oxygen and surface OH species. As a consequence, the Pt/Fe2O3-HO catalyst exhibited impressively high and stable activity towards HCHO oxidation at room temperature, which was five-fold higher than that of the supported Pt catalyst on commercial α-Fe2O3.