▎ 摘　　要

Platinum-free electrocatalysts for methanol oxidation are developed. The catalysts are composed of highly or-dered porous titanium dioxide nanotubes (TNTs) decorated with sole NiO (TNi) or functionalized with NiO/ graphene (TNiG). XRD proves the formation of the anatase phase in a composite with NiO and graphene. Raman spectra reveal the anatase peaks besides the D and G bands of graphene. SEM images show an ultrafine structure of TNTs with an average diameter of 50 nm and tube lengths lie in the range of 580 -640 nm with a wall thickness of 6 nm covered with a uniformly dispersed spherical Ni species. The XPS spectra verify the existence of Ni (OH)2 and NiOOH alongside metallic Ni on the TNT surface. The methanol oxidation test demonstrates a high current density for TNiG that is 73.6 mA/cm2 compared to 36.7 mA/cm2 for TNi at a scan rate of 5 mV/s attaining comparable values to noble metal/TNT composites. The high performance is attributed to the high surface coverage of the TNiG catalyst which is one order of magnitude higher than the TNi catalyst. Surface modification of TNT with Ni and G is found to facilitate the adsorption of methanol and alters the electronic properties, thereby promoting the methanol electro-oxidation activity.