High pressure volumetric apparatus for measurement of hydrogen adsorption capacity and kinetics (abbreviations: FI, flow indicator; PI, pressure indicator; PT, pressure transmitter; TC, thermocouple; , reference volume; , sample cell volume; VSL, vented to safe location).
Low range accuracy of pressure transmitter.
Parameters for extension of Sircar’s method of estimating helium adsorption by Henry’s law.
Reproducibility of AX-21 adsorption and desorption isotherms at for various pressure steps (◻) , (△) , and (○) . Filled markers represent desorption. GX-31 data from Ref. 18.
Comparison of hydrogen adsorption data from high pressure volumetric system and Micromeritics® ASAP 2010 at .
Hydrogen adsorption and desorption isotherms for at . Filled markers represent desorption. Curves are from Refs. 62 and 63.
Hydrogen adsorption and desorption isotherms for graphite at . Filled markers represent desorption.
Hydrogen adsorption and desorption isotherm for molecular sieve 5A at . Filled markers represent desorption. Inset: comparison of Ref. 66 For .
Hydrogen adsorption and desorption isotherm for SWNT at . Filled markers represent desorption.
Effect of omitting helium adsorption during free space measurement at . Data for AX-21 as in Fig. 4.
Pressure and temperature response to illustrate mole count stability for adsorption step.
Kinetics of hydrogen adsorption on AX-21 at for (△) , (◻) , and (○) . Inset: estimate of diffusion time constant as a function of pressure.
Hydrogen capacity for templated carbon spillover receptor with (○) or (◻) platinum particles as spillover source. Physisorption on plain templated carbon (△) is shown for comparison.
Kinetics for hydrogen spillover on Pt on TC at for (◻) , (△) , and (○) . Inset: estimated diffusion time constant as a function of pressure.
Henry’s law constants for microporous adsorbents at
Uncertainty in measured variables for the high pressure adsorption apparatus.
Materials studied to demonstrate instrument accuracy.
Variation of the amount adsorbed for manifold temperature fluctuation. Note: Valve opened at (i.e., first data point is into adsorption event).
Values of the diffusion time constant for AX-21.
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