la9046758_si_001.pdf (101.67 kB)
Measurements of Hydrogen Spillover in Platinum Doped Superactivated Carbon
journal contribution
posted on 2010-10-05, 00:00 authored by Nicholas P. Stadie, Justin J. Purewal, Channing C. Ahn, Brent FultzHydrogen uptake was measured for platinum doped superactivated
carbon at 296 K where hydrogen spillover was expected to occur. High
pressure adsorption measurements using a Sieverts apparatus did not
show an increase in gravimetric storage capacity over the unmodified
superactivated carbon. Measurements of small samples (∼0.2
g) over long equilibration times, consistent with the reported procedure,
showed significant scatter and were not well above instrument background.
In larger samples (∼3 g), the hydrogen uptake was significantly
above background but did not show enhancement due to spillover; total
uptake scaled with the available surface area of the superactivated
carbon. Any hydrogen spillover sorption was thus below the detection
limit of standard volumetric gas adsorption measurements. Due to the
additional mass of the catalyst nanoparticles and decreased surface
area in the platinum doped system, the net effect of spillover sorption
is detrimental for gravimetric density of hydrogen.