摘要:
An exemplary fuel cell of the invention includes a formic acid fuel solution in communication with an anode (12, 134), an oxidizer in communication with a cathode (16, 135) electrically linked to the anode, and an anode catalyst that includes Pd. An exemplary formic acid fuel cell membrane electrode assembly (130) includes a proton-conducting membrane (131) having opposing first (132) and second surfaces (133), a cathode catalyst on the second membrane surface, and an anode catalyst including Pd on the first surface.
摘要:
Novel metal organic framework (MOF) molecules and methods of synthesizing them are described. MOFs are organometallic crystalline structures that have high sorption capacity due to high surface area, tailorable selectivity, an inert nature, and thermal stability at high temperatures. MOFs may be used as sorbents in preconcentrators for analytical devices to provide orders of magnitude of improved sensitivity in analyte detection. MOFs are also useful as sorbents in new compact and portable micropreconcentrator designs such as a modified purge and trap system and a multi-valve microelectromechanical system (MEMS) to achieve high gain in analyte detection. Further, MOFs may be used as coatings for novel microstructure arrays in micropreconcentrators where the microstructures are designed to increase the surface area to volume ratio inside the micropreconcentrator while minimizing the pressure drop across the micropreconcentrator.
摘要:
A low contaminant formic acid fuel is especially suited toward use in a direct organic liquid fuel cell. A fuel of the invention provides high power output that is maintained for a substantial time and the fuel is substantially non-flammable. Specific contaminants and contaminant levels have been identified as being deleterious to the performance of a formic acid fuel in a fuel cell, and embodiments of the invention provide low contaminant fuels that have improved performance compared to known commercial bulk grade and commercial purified grade formic acid fuels. Preferred embodiment fuels (and fuel cells containing such fuels) including low levels of a combination of key contaminants, including acetic acid, methyl formate, and methanol.
摘要:
A bi-directional electrostatic microvalve includes a membrane electrode that is controlled by application of voltage to fixed electrodes disposed on either side of the membrane electrode. Dielectric insulating layers separate the electrodes. One of the fixed electrodes defines a microcavity. Microfluidic channels formed into the electrodes provide fluid to the microcavity. A central pad defined in the microcavity places a portion of the second electrode close to the membrane electrode to provide a quick actuation while the microcavity reduces film squeezing pressure of the membrane electrode. In preferred embodiment microvalves, low surface energy and low surface charge trapping coatings, such as fluorocarbon films made from cross-linked carbon di-fluoride monomers or surface monolayers made from fluorocarbon terminated silanol compounds coatings coat the electrode low bulk charge trapping dielectric layers limit charge trapping and other problems and increase device lifetime operation.
摘要:
Electrocatalysts for carbon dioxide conversion include at least one catalytically active element with a particle size above 0.6 nm. The electrocatalysts can also include a Helper Catalyst. The catalysts can be used to increase the rate, modify the selectivity or lower the overpotential of electrochemical conversion of CO2. Chemical processes and devices using the catalysts also include processes to produce CO, HCO−, H2CO, (HCO2)−, H2CO2, CH3OH, CH4, C2H4, CH3CH2OH, CH3COO−, CH3COOH, C2H6, (COOH)2, or (COO−)2, and a specific device, namely, a CO2 sensor.
摘要:
Catalysts that include at least one catalytically active element and one helper catalyst can be used to increase the rate or lower the overpotential of chemical reactions. The helper catalyst can simultaneously act as a director molecule, suppressing undesired reactions and thus increasing selectivity toward the desired reaction. These catalysts can be useful for a variety of chemical reactions including, in particular, the electrochemical conversion of CO2 or formic acid. The catalysts can also suppress H2 evolution, permitting electrochemical cell operation at potentials below RHE. Chemical processes and devices using the catalysts are also disclosed, including processes to produce CO, OH−, HCO−, H2CO, (HCO2)−, H2CO2, CH3OH, CH4, C2H4, CH3CH2OH, CH3COO−, CH3COOH, C2H6, O2, H2, (COOH)2, or (COO−)2, and a specific device, namely, a CO2 sensor.
摘要:
A rapid, simple and versatile metal organic framework molecule (MOF) synthesis method particularly adapted to make non-linear MOFs includes heating MOF precursors, such as a metal or metal oxide and an organic ligand, in a microwave oven for a period sufficient to achieve crystallization. Microwave-assisted MOF synthesis yields high quality MOF crystals in a reaction time ranging from about 5 seconds to about 2.5 minutes, compared to hours and days required in conventional solvothermal and hydrothermal methods. In addition, microwave assisted methods provide MOF materials with uniform crystal size and well-defined shape. Further, microwave synthesis of MOFs allows the size and shape of MOF crystals to be tailored for use in a wide range applications by manipulating reaction conditions. Secondary growth processes may also be employed to grow larger crystals using seeds obtained from microwave-assisted synthesis methods.
摘要:
Improved microcolumns and methods for producing microcolumns particularly suitable for use in gas chromatographs are disclosed. In particular, following deposition of the stationary phase coating, the microcolumns are subjected to a postcoating treatment with a molecule that binds to the active sites in the stationary phase column thereby eliminating or reducing loss of gas chromatograph performance associated with those active sites. The postcoating treatment molecule binds to the same active sites as the analytes of interest.
摘要:
A rapid, simple and versatile metal organic framework molecule (MOF) synthesis method particularly adapted to make non-linear MOFs includes heating MOF precursors, such as a metal or metal oxide and an organic ligand, in a microwave oven for a period sufficient to achieve crystallization. Microwave-assisted MOF synthesis yields high quality MOF crystals in a reaction time ranging from about 5 seconds to about 2.5 minutes, compared to hours and days required in conventional solvothermal and hydrothermal methods. In addition, microwave assisted methods provide MOF materials with uniform crystal size and well-defined shape. Further, microwave synthesis of MOFs allows the size and shape of MOF crystals to be tailored for use in a wide range applications by manipulating reaction conditions. Secondary growth processes may also be employed to grow larger crystals using seeds obtained from microwave-assisted synthesis methods.
摘要:
A direct formic acid fuel cell includes a cathode current collector having a perpendicularly extending edge that is capable of cooperating with the perpendicularly extending edge of an anode current collector to effect a press fit. The configuration seals fluids disposed within the volume formed between the current collectors.