Enhanced Formaldehyde Oxidation Performance of the Mesoporous TiO₂(B)-Supported Pt Catalyst: The Role of Hydroxyls

Abstract

As one of the crystal phases of titania, TiO 2 (B) was first utilized as a catalyst carrier for the oxidation of formaldehyde (HCHO). The mesoporous TiO 2 (B) loaded with Pt nanoparticles enhanced the HCHO oxidation reaction whose reaction rate was 4.5–8.4 times those of other crystalline TiO 2 -supported Pt catalysts. Simultaneously, Pt/TiO 2 (B) exhibited long-term stable HCHO oxidation performance. The structural characterization results showed that in comparison with Pt/anatase, Pt/TiO 2 (B) had more abundant hydroxyls, facilitating increasing the content of oxygen species. Studies on the role of hydroxyls in HCHO oxidation of Pt/TiO 2 (B) illustrated that synergistic involvement of terminally bound hydroxyls and bridging hydroxyls in HCHO oxidation accelerated the transformation from HCHO to formate via dioxymethylene. Moreover, hydroxyls could avoid the accumulation of excessive formate on Pt/TiO 2 (B) and promote the rapid oxidation of CO. Accordingly, the hydroxyl groups could accelerate each substep of formaldehyde oxidation, which enabled Pt/TiO 2 (B) to exhibit excellent formaldehyde oxidation performance.

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“…1(b). Titanium dioxide nanowire supported Pt showed a hysteresis loop of type H3 according to the IUPAC classification, indicating a mesoporous structure 28 . Pore size distribution was calculated using the BJH model 29 .…”

“…Titanium dioxide nanowire supported Pt showed a hysteresis loop of type H3 according to the IUPAC classification, indicating a mesoporous structure. 28 Pore size distribution was calculated using the BJH model. 29 The pore diameter (dp), mainly ranging from 2-50 nm, was observed for Pt/TiO 2 indicating mesoporous pores.…”