In situ synthesis of surfactant-free Pt nanoparticles supported on multi-walled carbon nanotubes under visible light

This paper presents the visible light-assisted synthesis of surfactant-free Pt nanoparticles (Pt-NPs) supported on multi-walled carbon nanotubes (MWCNTs) at ambient condition. Transmission electron microscopy (TEM) images indicate that Pt-NPs with high density and relative small in size (about 2 nm) were monodispersed on the surface of MWCNTs. The characterizations of Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD) and ultraviolet–visible spectroscopy (UV–Vis) prove that visible light irradiation significantly affect the species distribution of [PtCl4]2− precursor in the hydrolysis and then promote hydrolysate Pt oxides loading on MWCNTs. The loading process decides the morphology of Pt-NPs rather than the following precursor reduction, which does not change the morphology but only the valance state of platinum. The catalytic activity of Pt/MWCNTs was tested in subsequent methanol electrochemical reactions and 4-nitrophenol (4-NP) reduction.