Facile Controlled Synthesis of Pt/MnO₂ Nanostructured Catalysts and Their Catalytic Performance for Oxidative Decomposition of Formaldehyde

Abstract

Pt/MnO₂ nanostructured catalysts with cocoon-, urchin-, and nest-like morphologies were synthesized by a facile method. The synthesized MnO₂ nanostructures and Pt/MnO₂ catalysts were characterized by means of X-ray diffraction (XRD), N₂ adsorption–desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). TEM analyses showed that Pt nanoparticles of 1–4 nm were evenly dispersed on the surface of three MnO₂ nanostructures, and no Pt nanoparticle agglomeration occurred in the Pt/MnO₂ catalysts. These Pt/MnO₂ catalysts showed much higher catalytic activities than the corresponding MnO₂ nanostructures for oxidative decomposition of formaldehyde. Comparison of Pt/MnO₂ catalysts with varied Pt loadings and MnO₂ morphologies revealed that 2 wt % is the optimal Pt loading, and 2 wt % Pt/nest-like MnO₂ showed the highest catalytic activity for oxidative decomposition of formaldehyde (temperature for complete decomposition of HCHO is 70 °C). The high dispersion and small size of Pt nanoparticles and the synergistic effect between the Pt nanoparticle and MnO₂ nanostructure are considered to be the main reasons for the observed high catalytic activity of Pt/nest-like MnO₂