University of Nottingham, University Park, Nottingham NG7 2RD, UK.
ACS Appl Mater Interfaces. 2013 Jun 26;5(12):5639-47. doi: 10.1021/am401622w. Epub 2013 Jun 11.
Palladium nanoparticles are deposited onto zeolite template carbon (ZTC) via supercritical CO2 (scCO2) mediated hydrogenation of a CO2-phillic transition metal precursor. The supercritical fluid (SCF) mediated metal incorporation approach enabled the decoration of ZTC with 0.2-2.0 wt % of well-dispersed Pd nanoparticles of size 2-5 nm. The resulting Pd-doped ZTCs exhibit enhanced hydrogen uptake and storage density. The ZTC (with surface area of 2046 m(2)/g) had a hydrogen storage capacity (at 77 K and 20 bar) of 4.9 wt %, while the Pd-ZTCs had uptake of 4.7-5.3 wt % despite a surface area in the range 1390-1858 m(2)/g. The Pd-ZTCs thus exhibit enhanced hydrogen storage density (14.3-18.3 μmol H2/m(2)), which is much higher than that of Pd-free ZTC (12.0 μmol H2/m(2)). The hydrogen isosteric heat of adsorption (Qst) was found to be higher for the Pd-doped carbons (6.7 kJ/mol) compared to the parent ZTC (5.3 kJ/mol). The deposition of small amounts of Pd (up to 2 wt %) along with well-dispersed Pd nanoparticles of size of 2-5 nm is essential for the enhancement of hydrogen uptake and illustrates the importance of optimizing the balance between metal loading/particle size and surface area to achieve the best metal/porous carbon composite for enhanced hydrogen uptake.
钯纳米颗粒通过超临界 CO2（scCO2）介导的亲 CO2 过渡金属前体的加氢作用沉积在沸石模板碳（ZTC）上。超临界流体（SCF）介导的金属掺入方法使 ZTC 能够负载 0.2-2.0wt%的尺寸为 2-5nm 的分散良好的 Pd 纳米颗粒。所得 Pd 掺杂 ZTC 表现出增强的氢气吸收和存储密度。ZTC（比表面积为 2046m²/g）的储氢能力（在 77K 和 20bar 下）为 4.9wt%，而 Pd-ZTC 的吸收量为 4.7-5.3wt%，尽管其比表面积在 1390-1858m²/g 范围内。因此，Pd-ZTC 表现出增强的储氢密度（14.3-18.3μmol H2/m²），远高于无 Pd 的 ZTC（12.0μmol H2/m²）。发现掺杂 Pd 的碳的氢气等吸附热（Qst）（6.7kJ/mol）高于母体 ZTC（5.3kJ/mol）。少量 Pd（高达 2wt%）的沉积以及尺寸为 2-5nm 的分散良好的 Pd 纳米颗粒对于提高氢气吸收至关重要，这说明了优化金属负载/颗粒尺寸和表面积之间的平衡以实现最佳金属/多孔碳复合材料对于提高氢气吸收的重要性。
