Multiphase PtPdSb nanoparticles for direct electrochemical energy conversion using hydrogen-rich dimethyl ether

Abstract

Dimethyl ether (DME) is a promising next-generation renewable fuel for polymer electrolyte membrane fuel cells (PEMFC) because of its high energy density, ease of handling and supply, nontoxicity, reduced crossover, and ability to be obtained from a wide range of renewable sources. However, its commercialization has not yet been realized, owing to the low activity of state-of-the-art catalysts. We have synthesized a novel Genkenite ternary metal catalyst, PtxPdySbz/C, with varying metal compositions and tested its activity towards DME oxidation in both three-electrode flooded cell and in single fuel cell configurations. Some important insights into the DME reaction mechanism were gleaned using ex-situ Fourier transform infrared spectroscopy and were supported by density functional theory (DFT) computations. A direct DME fuel cell constructed with 1.2 and 3.1 mgPGM cm􀀀 2 loading of Pt5PdSb4/C and Pt/C as anode and cathode catalysts, respectively, operating at 65 ◦C temperature and no back pressure delivered a peak power density of 180 mW cm􀀀 2 and one of the highest reported current density of 360 mA cm􀀀 2 at 0.5 V. Moreover, the catalyst provided the highest PGM (Pt+Pd) mass normalized power density of 150 mW mg􀀀PG1M.