Sepiolite nanofiber-supported platinum nanoparticle catalysts toward the catalytic oxidation of formaldehyde at ambient temperature: Efficient and stable performance and mechanism

Sepiolite nanofiber-supported platinum nanoparticle (Pt/sepiolite) catalysts were prepared by a reductive impregnation process, and were used for the efficient and stable removal of formaldehyde (HCHO). TEM and HRTEM analyses indicate that Pt nanoparticles with 2–4 nm in size were highly dispersed on sepiolite nanofibers with diameters of 50–150 nm. FTIR and XPS spectra show the presence of abundant hydroxyls on the catalyst surface. At ambient temperature, 1 wt.% Pt/sepiolite catalyst calcined at 400 °C exhibited the highest catalytic activity for the oxidation of HCHO to CO2 and H2O, and still showed a good performance even after 7 cycles. The mechanism of the catalytic oxidation of HCHO was studied through the behaviors of adsorbed species on the catalyst surface using in situ DRIFTS. The efficient and stable catalytic performance of the Pt/sepiolite catalyst mainly results from the synergistic effect between the hydroxyls on sepiolite nanofibers and highly dispersed Pt nanoparticles. This work may provide new insights for the application of noble metal catalysts supported on natural low-cost clays with special function groups in the removal of indoor air pollutants.