MnO₂ Promoted TiO₂ Nanotube Array Supported Pt Catalyst for Formaldehyde Oxidation with Enhanced Efficiency

Abstract

Highly ordered pore-through TiO2 nanotube arrays (TiNT) prepared by an electrochemical anodization method were modified with MnO2 and used as the support for a Pt/MnO2/TiNT catalyst. The monolith-like Pt/MnO2/TiNT was then applied to low-concentration HCHO oxidation with enhanced efficiency. The effect of the MnO2 promotion on its performance for HCHO oxidation was studied with respect to the behavior of adsorbed species on the catalyst surface using in situ diffuse reflectance Fourier transform spectroscopy. In comparison with Pt/TiNT, Pt/MnO2/TiNT shows higher activity under parallel preparation and test conditions. A HCHO conversion of 95% with a more than 100 h stable performance is achieved over Pt/MnO2/TiNT at 30 °C with a low 0.20 wt % Pt loading amount. The superior performance is related to the specific monolith-like structure and its confinement effect, metal–support interaction, and superior HCHO adsorption and storage properties of Pt/MnO2/TiNT.