Electrocatalytic Evaluation of Highly Stable Pt/ZrO2 Electrocatalysts for the Methanol Oxidation Reaction Synthesized Without the Assistance of Any Carbon Support

Zirconium oxide has been proposed as an alternative to carbon supports due to its high electrochemical stability at high electrode potential values. However, its low electrical conductivity has limited its use. In this work, we successfully overcome this issue by synthesizing Pt electrocatalysts directly on ZrO2 supports. The ZrO2 supports were obtained through a sol-gel method at 350 degrees C (ZrO2-350) and 500 degrees C (ZrO2-500) calcination temperatures, obtaining surface areas of 82 and 92 m(2) g(-1) and crystalline phases corresponding to the tetragonal and mixture of tetragonal and monoclinic phases, respectively. Pt nanoparticles synthesized directly on ZrO2 had particle sizes of 3.0 +/- 0.3 nm and 6.0 +/- 0.8 nm for Pt/ZrO2-350 and Pt/ZrO2-500, respectively. Pt/ZrO2-350 and Pt/ZrO2-500 presented similar onset potentials (-0.34 V and -0.33 V) and current densities (249.3 mA mg(-1) and 255.8 mA mg(-1)) than a commercial Pt/C (-0.39 V, 277.5 mA mg(-1)) during the electro-oxidation of 2 M methanol in alkaline medium. Regarding catalyst stability, Pt/ZrO2-500 kept 96 % of its initial current after 500 cycles, while Pt/C maintained 49 % of its initial current.