Deactivation and regeneration of Pt/TiO2 nanosheet-type catalysts with exposed (0 0 1) facets for room temperature oxidation of formaldehyde

• Oxidative decomposition of formaldehyde on Pt/TiO2 occurs at room temperature.
• Fluoride poisoning phenomenon of Pt/TiO2 nanosheets is explained.
• This poisoning is due to F-blocking of Pt catalytic active sites.
• Pt/TiO2 nanosheet-type catalysts can be easily regenerated by washing with NaOH solution.

Formaldehyde (HCHO) is a major indoor air pollutant and long-term exposure to HCHO may cause health problems including nasal tumors and skin irritation. Room-temperature catalytic oxidation decomposition of HCHO is considered as the most promising strategy for the removal of HCHO due to its environmental-friendly reaction conditions and energy-saving consideration. In this work, surface-fluorinated anatase TiO2 nanosheets with dominant {0 0 1} facets (FTiO2-NS) were first prepared by a hydrothermal method using Ti(OC4H9)4 and HF as precursors. Then, Pt/FTiO2-NS catalyst with 0.5 wt% Pt loadings was obtained by a combined NaOH-assisted impregnation of titania with Pt precursor and NaBH4-reduction route. The catalytic activity was evaluated by catalytic oxidation decomposition of HCHO vapor at room temperature. Fluoride poisoning (F-poisoning) phenomenon of Pt/FTiO2-NS was first observed for oxidative decomposition of HCHO. The mechanism of F-poisoning is mainly due to blocking of Pt catalytic active sites by strong interactions between Pt and highly electronegative F. In order to recover the catalytic performance, a simple regeneration method for the deactivated Pt/FTiO2-NS catalysts was proposed by NaOH washing.

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