Nanoporous carbon-templated silica nanoparticles: Preparation, effect of different carbon precursors, and their hydrogen storage adsorption

New nanoporous carbon materials were synthesized using a nano-casting method with agglomerated porous silica nanoparticles that originated from rice husk as an inorganic template material and sucrose and glycerol as carbon precursors. The nanoporous carbon materials obtained have a specific surface area that reached 749 m2/g and a pore volume of 1.44 cm3/g. The type and molecular size of the carbon precursor played a significant role for the textural properties of the resulting carbon materials. The hydrogen storage capacity of the porous rice husk silica nanoparticles and the nanoporous carbon materials from the two carbon sources have been investigated at different temperature and pressure. In addition, the effect of the slit-shaped pore structure has been demonstrated. The highest excess hydrogen adsorption was found to be 2.41 wt.% achieved at 77 K and 7.3 MPa and the total hydrogen uptake was 5.7 wt.% at 77 K and 7.3 MPa. The isosteric heat of adsorption of the nanoporous carbon materials has been investigated and reached 7.3 kJ/mol which was higher than the values reported on porous activated carbon AX-21_33 (5.53 kJ/mol), Norit R0.8 (5 kJ/mol), and metal–organic frameworks MOF-177 (3.7 kJ/mol), MOF-5 (4 kJ/mol).

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► Cost-effective mesoporous carbon materials with a large pore volume and slit-shaped pores have been synthesized.
► The type of carbon precursor affects the porosity and the hydrogen storage performance.
► The slit-shaped pore structure showed a significant effect in enhancing the heat of hydrogen adsorption.
► The average values for the heat of adsorption were found to be in the range of 6.8 and 7.3 kJ/mol.
► The pore volume contributed significantly to the total hydrogen storage capacity.