Cu-Pt Bi-Metallic Catalysts By Continuous Electroless Deposition for Methanol Oxidation Reaction

Abstract

Direct methanol fuel cells (DMFCs) are one promising alternative energy storage solution that circumvents one of the chief challenges of current hydrogen fuel cell technology, the elimination of the hydrogen storage step (liquid methanol storage being far more easily handled and transported than compressed H2). However, a severe limitation to DMFCs is the deactivation of Pt catalysts from reaction byproducts, specifically CO from the oxidation of methanol. CO strongly chemisorbs onto Pt sites, reducing the operating efficiency of the fuel cell. As a result, more research is being done into the use of another metal alongside Pt to improve its catalytic activity. Cu is a promising candidate to be incorporated into these catalysts. As bimetallic Cu-Pt catalysts have been shown to have increased activity towards methanol oxidation reaction (MOR) [1, 2]. Cu drastically improves the oxidation of CO, protecting the Pt sites from poisoning [3], and additionally, the presence of Cu increases the amount of surface defects, improving the number of active sites present [4]. In this work, a series of carbon supported Pt-Cu catalysts were prepared by using continuous electroless deposition method. This method was used to produce highly-controlled compositions of Pt-Cu bimetallic catalysts that enhance the catalytic activity of pure Pt. The series of carbon supported Pt-Cu then characterized and evaluated for MOR. The XRD, chemisorption, STEM analysis in addition to cyclic voltammetry in acidic environment have been used for evaluation of these sets of catalysts. XRD and STEM analysis indicated the alloy formation, and the cyclic voltammetry results have shown higher activity towards methanol oxidation in comparison to the commercial supported Pt. References Zhunze Su, et al., Journal of Power Sources, 2015, 279 (1), 2015, pp 334-342.Chatwarin Poochai, et al., Materials Chemistry and Physics, 2015, 163 (1), 2015, pp 317-3303.Lin Han, et al., Journal of Power Sources, 2015, 286, pp 488-494Eric J. Coleman, et al., ACS Catal., 2015, 5 (2), pp 1245–1253