Development of a simple and efficient method to prepare a platinum-loaded carbon electrode for methanol electrooxidation

Abstract In this study, a simple and efficient electrochemical method was developed to prepare platinum (Pt) nanoparticles modified pencil graphite electrode (PGE) to use in direct methanol fuel cells. This method is based on two successive steps including the electrochemical pre-treatment of PGE via potential sweeping in the range of −1.0 V and +2.0 V and subsequent electrochemical plating of Pt nanoparticles in a wide potential range (+2.0 V: 1.0 V). Both the electrochemical pre-treatment of PGE and to use a wide potential range in the electrochemical Pt plating tremendously increased the effective surface area, the intensity of surface functional groups (hydroxyl, carbonyl, carboxyl, etc.), the electron transfer rate and the amount of Pt loading on the electrode surface, which greatly improved methanol electrooxidation activity of the electrode. The increase in the activity of the electrode reached to 16.3 times according to the classical Pt electroplating process. The electrodes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy measurements. The stability of the electrodes was tested via cyclic voltammetry and chronoamperometry measurements. The electrochemical surface area of the electrode prepared here was calculated as 39.46 m2 g-1, which was 39% higher than that of commercial Pt/C catalyst (28.4 m2 g-1). The results showed that the proposed modification process can be seen as a simple and efficient alternative for the preparation of Pt-loaded carbon electrodes which can be used in direct methanol fuel cells.