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.