Abstract: The electrocatalysts in certain fuel cell systems can be poisoned by impurities in the fuel stream directed to the fuel cell anodes. Introducing a variable concentration of oxygen into the impure fuel stream supplied to the fuel cells can reduce or prevent poisoning without excessive use of oxygen. The variation may be controlled based on the voltage of a carbon monoxide sensitive sensor cell incorporated in the system. Further, the variation in oxygen concentration may be periodic or pulsed. A variable air bleed method is particularly suitable for use in solid polymer fuel cell systems operating on fuel streams containing carbon monoxide.

Abstract: A method detects fluid leaks within a fuel cell assembly. The method comprises (a) introducing a first supply fluid to a first fluid passage within the fuel cell assembly, wherein the first supply fluid comprises a tracer; (b) introducing a second supply fluid to a second fluid passage within the fuel cell assembly, wherein in the absence of a leak in the first fluid passage, the second fluid passage is fluidly isolated from the first fluid passage; and (c) monitoring a second fluid exhaust stream exiting from the second fluid passage and detecting when a concentration of the tracer is present within the second fluid exhaust stream.

Abstract: Application of two-dimensional materials (TDMs) that are exfoliated transition metal dichalcogenides in electrochemical fuel cells to remove contaminants that are harmful to the fuel cells; to effect proper transport and containment of various fluids in fuel cells to achieve proper and efficient operation; to protect various surfaces and materials commonly comprised in or used for fuel cells and critical to their operation; and to purify and lower the freezing point of cooling water used for the fuel cell stacks. Disclosed are methods whereby the TDM is used as a barrier to prevent unwanted crossover (between electrodes through a polymer electrolyte membrane or PEM) of chemical species; where the TDM is used to coat and/or encapsulate catalyst particles, carbon catalyst support, PEMs, and chemical or metal hydrides, to protect the same from unwanted exposure to chemical species; and where the TDM is used to purify and lower the freezing point of fuel cell stack cooling water.

Abstract: Various systems, method and apparatuses are disclosed that include a pressure swing adsorption apparatus coupled to a fuel cell, wherein the fuel cell receives at least a portion of a product gas from the pressure swing adsorption and powers the pressure swing adsorption apparatus. Also disclosed is a portable gas separator that include a housing that houses a rotary pressure swing adsorption apparatus.

Abstract: Power plant systems and processes are described that enable recovery of at least a portion of the fuel storage energy associated with a storage system for supplying fuel to the power plant systems. A first embodiment of an energy-recovery power plant system includes at least one fuel storage container and at least one expander that can receive fuel from the fuel storage container at a first pressure and provide the fuel to the power plant at a second pressure that is lower than the first pressure. A second embodiment of an energy-recovery power plant system includes a first conduit fluidly coupling the fuel storage container and the power plant for delivering fuel from the fuel storage container to the power plant and at least one regenerative thermodynamic cycle engine thermally coupled to the first conduit such that heat may be exchanged between the fuel and a working fluid for the regenerative thermodynamic cycle engine.

Abstract: An improved fuel cell anode structure comprises a substrate and a first carbon-based component. The first carbon-based component exhibits little or no resistance to corrosion. When said anode structure is incorporated into a membrane electrode assembly, the membrane electrode assembly is tolerant to incidences of cell voltage reversal.

Abstract: The electrocatalysts in certain fuel cell systems can be poisoned by impurities in the fuel stream directed to the fuel cell anodes. Introducing a variable concentration of oxygen into the impure fuel stream supplied to the fuel cells can reduce or prevent poisoning without excessive use of oxygen. The variation may be controlled based on the voltage of a carbon monoxide sensitive sensor cell incorporated in the system. Further, the variation in oxygen concentration may be periodic or pulsed. A variable air bleed method is particularly suitable for use in solid polymer fuel cell systems operating on fuel streams containing carbon monoxide.

Abstract: The electrocatalysts in certain fuel cell systems can be poisoned by impurities in the fuel stream directed to the fuel cell anodes. Introducing a variable concentration of oxygen into the impure fuel stream supplied to the fuel cells can reduce or prevent poisoning without excessive use of oxygen. The variation may be controlled based on the voltage of a carbon monoxide sensitive sensor cell incorporated in the system. Further, the variation in oxygen concentration may be periodic or pulsed. A variable air bleed method is particularly suitable for use in solid polymer fuel cell systems operating on fuel streams containing carbon monoxide.