The 2-Propanol Fuel Cell: A Review from the Perspective of a Hydrogen Energy Economy

Abstract

The 2-propanol fuel cell has been shown to hold several key advantages over the more established methanol fuel cell, including a comparably high real open-circuit voltage, reduced fuel crossover through a Nafion membrane and a benign toxicological fuel profile. In addition, while the highly selective partial oxidation of 2-propanol to acetone in a fuel cell (rather than the more typical complete combustion of organic fuels to CO2) has been viewed as a disadvantage in the past, recent work has shown that the 2-propanol/acetone couple is compatible with traditional hydrocarbon liquid organic hydrogen carrier (LOHC) systems though transfer hydrogenation. With this approach, a disadvantage of hydrogen LOHC logistics—the steep energy cost of dehydrogenation that must be provided during energy-lean times—can be largely avoided. This LOHC compatibility along with the potential for high fuel-cell performance could place the 2-propanol fuel cell (also referred to as the direct isopropanol fuel cell or DIFC) in a position to enable a hydrogen energy economy while avoiding the drawbacks of molecular hydrogen transport and storage. In this Review, the purpose is to ascertain the state-of-the-art of DIFCs—an understudied yet promising research area with unique advantages and challenges.