Methyl orange-modified Au nanoparticles supported on multiwalled carbon nanotubes as an electrocatalyst for methanol oxidation

The most stable metal-gold (Au) is not usually used as a catalyst component. To explore the catalytic activity of Au, Au colloidal nanoparticles were synthesized by a photochemical method and modified by methyl orange (MO) into modified Au colloidal nanoparticles solution (Au-MO). Then, Au-MO/multiwalled carbon nanotubes (Au-MO/MWCNTs) catalysts were obtained by supporting the Au-MO on the MWCNTs. The structure characterization revealed that MO attracts the electrons of Au, and electron transfer occurs from the Au nanoparticles to MO in the Au-MO/MWCNTs catalyst. Electrochemical measurements demonstrated that Au-MO/MWCNTs have a distinctly higher electrocatalytic activity for methanol oxidation than that of the Au/MWCNT catalyst. It was found that the improved electrocatalytic activity of the Au- MO/MWCNTs is derived from the electron transfer from the Au nanoparticles to MO.