4A-Zeolite Enhanced Electrocatalytic Activity of Pt/C for Electrooxidation of Methanol in Alkaline Medium

Abstract

Pt-based electrocatalyst is considered to be the most efficient materials in direct methanol fuel cells [1]. However, the high cost of noble metals inhibits their application in fuel cells on a large scale. Therefore, the effort to finding out an abundant, inexpensive and efficient electrocatalytic material is of great significance. Zeolite, composed of silicon-aluminum oxides, is well known for its ion exchange property, adsorption with of acidic protonic entities and porosity on its surface, making it more hydrophilic and facilitating the diffusion of analytes into the film of electrode surface as well as the enhancement of active area [2,3]. Furthermore, the lower resistance and less ohmic power losses can be obtained when zeolite is used as electrode materials. In this study, Pt/C catalyst was prepared by reducing H2PtCl6 with NaBH4 as reducer, and subsequently co-mixed with the porosity structured 4A-zeolite for the purpose of enhancing of the specific activity and reducing of the dosage of noble metal. The corresponding electrocatalytic activity for electrooxidation of methanol was evaluated in alkaline medium by cyclic voltammetry. It was shown that the electrocatalytic activity of the 4A-zeolite modified Pt/C catalyst was much better than that of Pt/C catalyst (Figure 1). This increased electrocatalytic activity could be attributed to that the micrometer 4A-zeolite with porosity structure could significantly increase the effective electrode surface and facilitate the diffusion of analytes into the film of electrode surface.