Synthesis of PtCo/ZSM-5/C electrocatalyst and electrochemical activity

Abstract

This study presents the synthesis and electrochemical characterization of a bimetallic PtCo electrocatalyst supported in a ZSM-5 zeolite and XC-72R Vulcan carbon 50 wt.% composite. Two synthesis methodologies were tested: reduction mediated by ethylene glycol and NaBH4. The catalyst electroactivity was assessed by measuring the electrochemical surface area, ESA, and the electrooxidation of methanol was evaluated by cyclic voltammetry and chronoamperometry in acid medium. The nanoelectrocatalysts were obtained with average particle size nearly 3.0 nm and ESA up to 44.7 m2 g−1, indicating the effectiveness of the synthesis methods and of the composite ZSM-5/C used as catalyst support. XPS studies showed that PtCo alloy was obtained by NaBH4 reduction. All samples presented good tolerance to carbonaceous species indicated by jf/jb ratio greater than 1 in methanol oxidation activity test. The 1-h chronoamperometry tests corroborated these results. Some samples obtained in the present work showed higher current density in steady state compared to the commercial sample used as reference and analyzed under the same experimental process. The results showed that the zeolite support was effective at improving catalytic activity independently of the alloy PtCo presence on the catalyst surface.