Enhanced activity of Pt nanoparticle catalysts supported on manganese oxide-carbon nanotubes for ethanol oxidation

Pt nanoparticles deposited on manganese oxide-carbon nanotubes (Pt/MnOx-CNTs) are prepared by a microwave-assisted polyol method. Their structure characterizations are carried out by Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) measurements, indicating that MnOx nanoparticles cover the surface of CNTs and then Pt nanoparticles are uniformly dispersed on MnOx-CNTs with the average particle size of about 2.2 nm. Ethanol oxidation peak current on Pt/MnOx-CNTs (1141.4 mA mg−1 Pt) is 1.82 times higher than that on Pt/CNTs (626.4 mA mg−1 Pt) and 1.28 times higher than that on PtRu/C (JM) (888.6 mA mg−1 Pt). The Pt/MnOx-CNT catalyst presents not only excellent electrocatalytic activity and very high stability for ethanol oxidation, but also high tolerance to the poisonous carbonaceous intermediates generated during ethanol oxidation compared to Pt/CNT catalyst. This is attributed to the excellent proton conductivity of MnOx and the synergistic effect between Pt and MnOx. The optimum mass ratio of MnOx to CNTs is 1:1 in the Pt/MnOx-CNT catalysts.