Effect of preparation conditions on the performance of nano Pt‒CuO/C electrocatalysts for methanol electro-oxidation

Nano PtCuO particles were deposited on Vulcan XC-72R carbon black using the impregnation and microwave irradiation methods. The prepared catalysts were characterized by XRD, TEM and EDX analyses. TEM images indicated that the microwave method provides homogeneously distributed catalyst particles in smaller size, compared to the one prepared by the impregnation method. The electrocatalytic activity of Pt‒CuO/C electrocatalysts was investigated to oxidize methanol in 0.5 M H2SO4 solution by applying cyclic voltammetry and chronoamperometry techniques. The oxidation current density of Pt‒CuO/C electrocatalyst, prepared by the microwave method, showed two folds increment with a potential shift in the negative direction by 69 and 36 mV at the first and second oxidation peaks, respectively, relative to those at the catalyst prepared by the impregnation method. The effect of varying methanol concentration on the resulting oxidation current density of Pt‒CuO/C electrocatalysts was studied. Some kinetic information about the reaction order with respect to methanol and Tafel slope values was calculated. Slower current density decay was observed in the chronoamperogram of Pt‒CuO/C electrocatalyst, prepared by the microwave method, reflecting a lower degree of surface poisoning.

Transmission electron microscopic image of Pt‒CuO/C electrocatalyst prepared by microwave irradiation method.Figure optionsDownload as PowerPoint slideHighlights
► Pt was reduced over CuO/C powder.
► The presence of CuO in Pt‒CuO/C catalysts decreases Pt crystallite size.
► Higher oxidation current density was gained at Pt‒CuO/C-2 catalyst.
► Higher If/Ib values were estimated at Pt‒CuO/C catalysts.