W. M. Keck Laboratory, California Institute of Technology, 138-78, Pasadena, California 91125, USA.
Langmuir. 2010 Oct 5;26(19):15481-5. doi: 10.1021/la9046758.
Hydrogen 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.
在预计会发生氢溢出的情况下，测量了掺铂超级活性炭在 296K 时的氢吸收量。使用 Sieverts 装置进行的高压吸附测量并未显示出比未经修饰的超级活性炭在重量存储容量上有增加。根据报道的程序，对小样品（约 0.2 克）进行长时间的平衡测量显示出显著的分散性，并且没有明显高于仪器背景。在较大的样品（约 3 克）中，氢的吸收量明显高于背景，但由于溢出没有增强；总吸收量与超级活性炭的可用表面积成正比。因此，任何由于溢出而导致的氢气吸附都低于标准体积气体吸附测量的检测限。由于催化剂纳米颗粒的额外质量和掺铂系统中表面积的减少，溢出吸附的净效应对氢气的重量密度是不利的。
