Ag@ Fe-TiO 2 catalysts for catalytic oxidation of formaldehyde indoor: a further improvement of Fe-TiO 2

In this paper, a series of Fe-doped TiO2 (Fe-TiO2) catalysts were prepared by ultrasonic hydrothermal method and were used to catalytic oxidation formaldehyde (HCHO) indoor at room temperature. Although the catalytic activity was improved compared with P25, but the final concentration of HCHO was still higher than the Chinese standard (GB 0.08 mg/m3), and the stability was restrict under room temperature. In order to improve the catalytic activity and stability of the catalysts, various concentrations of Ag were loaded on Fe-TiO2, and good catalytic oxidation effect was obtained and had a good repeat catalytic effect under room condition. UV–Vis, IR, PL, XRD, SEM, BET, XPS were used to characterize the materials. The results showed that the higher dispersion of active Ag, and the synergistic effect between Ag, Fe and TiO2 nanostructure were helpful to improve the catalytic oxidation ability of Ag@Fe-TiO2. In the repeat experiments, 0.6%Ag@0.3%Fe-TiO2 exhibited good catalytic activity and stability. The formaldehyde concentration was reduced to 0.05 mg/m3, after four rounds of tests, the formaldehyde concentration was still below 0.08 mg/m3, applying for long time indoor HCHO degradation at room temperature. Indicating the modification of Ag element can further promote the catalytic activity and stability of Fe-TiO2.