摘要:
Atomically dispersed platinum-group metal-free catalyst and method for synthesizing the same. According to one embodiment, the catalyst is made by a method in which, in a first step, a metal oxide/zeolitic imidazolate frameworks (ZIF) composite is formed by combining (i) nanoparticles of an oxide of at least one of iron, cobalt, nickel, manganese, and copper, (ii) a hydrated zinc salt, and (iii) an imidazole. Then, in a second step, the metal oxide/ZIF composite is thermally activated, i.e., carbonized, to form an M-N—C catalyst. Thereafter, the M-N—C catalyst may be mixed with a quantity of ammonium chloride, and then the M-N—C/NH4Cl mixture may be pyrolyzed. The foregoing NH4Cl treatment may improve the intrinsic activity of the catalyst. Then, a thin layer of nitrogen-doped carbon may be added to NH4Cl-treated M-N—C catalyst by chemical vapor deposition (CVD). Such CVD treatment may improve the stability of the catalyst.
摘要:
Waterless electrochemical transdermal alcohol sensor. In one embodiment, the sensor includes a proton exchange membrane imbibed with an imbibing liquid that includes at least one cationic substance that is liquid at room temperature. As examples, the cationic substance may be one or more ionic liquids with an imidazolium, phosphonium, ammonium, pyridinium, pyrrolidinium, or sulfonium backbone structure. The imbibing of the proton exchange membrane with the cationic substance obviates the need for the periodic addition of water to the electrochemical cell. The sensor additionally includes a sensing electrode, which is bonded to one side of the proton exchange membrane, and a counter electrode and a reference electrode, both of which are bonded to the opposite side of the proton exchange membrane. The sensor may be incorporated into a wearable transdermal alcohol sensor device, which, in turn, may be incorporated into a system for detecting transdermal alcohol.
摘要:
A three-dimensional, porous anode material suitable for use in a lithium-ion cell. The three-dimensional, porous anode material includes active anode particles embedded within a carbon matrix. The porous structure of this novel anode material allows for the expansion and contraction of the anode without the anode delaminating or breaking apart, thus improving the life-cycle of the lithium-ion cell. An example of this three-dimensional porous anode material is a porous silicon-carbon composite formed using a bi-continuous micro-emulsion (BME) template.
摘要:
In polymer electrolyte membrane (PEM) fuel cells and electrolyzes, attaining and maintaining high membrane conductivity and durability is crucial for performance and efficiency. The use of low equivalent weight (EW) perfluorinated ionomers is one of the few options available to improve membrane conductivity. However, excessive dimensional changes of low EW ionomers upon application of wet/dry or freeze/thaw cycles yield catastrophic losses in membrane integrity. Incorporation of ionomers within porous, dimensionally-stable perforated polymer electrolyte membrane substrates provides improved PEM performance and longevity. The present invention provides novel methods using micromolds to fabricate the perforated polymer electrolyte membrane substrates. These novel methods using micromolds create uniform and well-defined pore structures. In addition, these novel methods using micromolds described herein may be used in batch or continuous processing.
摘要:
System for modifying the chemical composition of atmosphere within an enclosed space and incubator system including such a system. The concentration of oxygen within the enclosed space may be either increased or decreased using an electrochemical device. The concentration of carbon dioxide within the enclosed space may be increased using an electrochemical or chemical device. As necessary, purging of the system with ambient air can be a part of the process of controlling the chemical composition of the atmosphere. The present invention obviates the need to use pressurized gas cylinders to supply atmospheric gases to the enclosed space.
摘要:
An electrochemical sensor is provided for the detection of carbon dioxide gas. The sensor includes a non-conductive solid substrate and at least one each of a metal oxide sensing electrode, a reference electrode and a counter electrode positioned on the substrate. A solid polymer electrolyte anion-exchange membrane is in intimate contact with the sensing electrode, reference electrode and counter electrode. The sensor is highly sensitive and selective to carbon dioxide and has very rapid response time.
摘要:
A graphite reference electrode for use in the cathodic protection of steel embedded in concrete has been produced with a stable catalyzed structure that when equilibrated with air or oxygen and an electrolyte reaches a reproducible and reversible redox potential. This stable device is produced by exposure to hydrogen peroxide, impregnating with a metal oxide followed by a coating treatment. The embedded catalyzed graphite reference electrodes can be used in impressed cathodic protection systems or monitoring the corrosion condition of embedded steel to provide an early warning of impending damage.
摘要:
A direct methanol fuel cell (DMFC) contains a membrane electrode assembly (MEA) including an anode porous electrode structure which can operate on a liquid or vapor methanol/water feed in the absence of a liquid electrolyte such as sulfuric acid, a proton-exchange membrane electrolyte, and a porous gas-diffusion cathode. The anode porous electrode structure includes a three-dimensional reduced (Pt--Ru)O.sub.x catalyst particle-ionomer composite structure, whereby the ionomer coats the individual particles and provides a mechanism for continuous proton transport throughout the composite structure, eliminating the need for a liquid acidic electrolyte. The partially reduced (Pt--Ru)O.sub.x particles are individually ionomer coated prior to anode fabrication. The anode porous electrode structure is subsequently bonded to one side of a thin sheet of a solid proton-conducting ionomer membrane and a cathode structure bonded to the opposite side of the membrane, to form a MEA. Insertion of the MEA into appropriate hardware results in fuel cell fabrication.
摘要:
A fuel cell comprising an anode, a cathode and an aqueous carbonate electrolyte, and including means for feeding carbon dioxide to at least one of the anode and cathode during operation of the cell. The addition of carbon dioxide provides a higher current density at a working potential.
摘要:
Method and system for controlling oxygen delivery to a cell implant. In one embodiment, the system includes a water electrolyzer, a cell capsule, a gas conduit, a total fluid pressure sensor, and a controller. The water electrolyzer generates gaseous oxygen with a variable output. The cell capsule includes a cell chamber adapted to hold cells. The gas conduit interconnects the water electrolyzer and the cell capsule to deliver gaseous oxygen generated by the water electrolyzer to the cell capsule. The total fluid pressure sensor is positioned at a location that provides a representative reading of the total fluid pressure within the cell chamber. The controller is electrically coupled both to the total fluid pressure sensor and to the water electrolyzer so that the controller may control the variable output of the water electrolyzer based on one or more sensed total pressure readings from the total fluid pressure sensor.