Stoichiometry, hierarchical arrangement and kinetics of electrode reactions at novel multi-components electrocatalytic materials

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The depletion of fossil fuel reserves and serious environmental issues has created tremendous energy challenges. It is now undeniable that electrochemistry- the interchange of chemical and electrical energy- is about to play a major role in energy production. As a clean, sustainable energy technology, direct ethanol fuel cells (DEFCs) have emerged as highly promising low carbon power sources for vehicles and as alternatives to rechargeable batteries in portable electronic devices. Yet, the commercialization of DEFCs is hindered by their low anode catalyst activities and the production of partial oxidation byproducts. In addition, proton exchange membranes-DEFCs are considered too bulky and costly, and they can be damaged by high concentrations of ethanol, known as the ethanol crossover effect. Our long-term objective is to develop membraneless mixed-reactants DEFCs (novel technology) with efficiency higher than 60%. Over the next five years, the main objective of our work is to develop and gain insights in the synthesis-structure-catalytic activity relationships of novel nanostructured highly active and efficient multicomponent anode catalysts for the electrocatalytic oxidation of ethanol (Theme I). Efforts will be focused on the addition of co-catalysts to platinum. We will choose materials composed of abundant and inexpensive metal oxide materials combined with ultra-low amounts of platinum and rhodium. We expect to discover the optimal structural arrangements of the atoms of the three components in the surface and bulk of the final active catalyst to maximize activity and selectivity. We will also develop selective cathode catalyst that is electroactive towards oxygen reduction reaction while tolerant to high concentrations of ethanol (Theme II). Considering that the size of oxygen molecule is much smaller than that of ethanol, our idea is develop a superficial material layer through which oxygen molecules can easily diffuse and be reduced at the platinum beneath layer surface while ethanol molecules remain impeded at the surface of the superficial layer. Like this higher ethanol concentrations could be used and superior electrochemical performance would be achieved. The results of this proposal will address Canada's research priority in the development of advanced nanomaterials based electrochemical clean/green technologies to deal with increasingly critical energy and environmental challenges as well as climate change, while training highly qualified personnel to exploit these opportunities. As to the fundamental issues, these studies will assist in establishing firm correlations between interfacial structures, compositions, and understanding of mechanistic aspects of new classes of catalytic materials. In addition, this proposed research program will be important to commercial applications in Canada such as, consumers' portable electronics and transport, or to specific users for road safety fuel cell-based sensors for ethanol detection.