No abstract

Template-free preparation of layer-stacked hierarchical porous carbons from cheap pitch precursors for high-performance all-solid-state supercapacitors.

Millimeter-sized activated carbon spheres are potential candidates for industrial-scale CO2 capture. Millimeter-sized sulfur-doped microporous activated carbon spheres were synthesized from poly­(styrene–divinylbenzene), a very cheap and easily operated resin product, in the present work and studied for CO2 uptake. A series of sulfur-doped spherical carbon materials were yielded through the sulfonation, oxidation, carbonization, and KOH activation of the polymer precursors. In addition to promoting the cross-linking of the polymer molecules, the sulfonic substituents directly introduced sulfur functional groups into the carbon materials after pyrolysis. The SCS-700 sample showed the best CO2 adsorption performance, whose sulfur content reached 0.69 wt %, and exhibited a high surface area of 1526 m2 g–1 and a large pore volume of 0.726 cm3 g–1. The adsorbent showed high CO2 uptake at both 25 °C (4.21 mmol g–1) and 50 °C (2.54 mmol g–1) under ambient pressure due to its abundant ultramicropores and a high proportion of oxidized sulfur functional groups. Thanks to its high microporous volume of 0.617 cm3 g–1, the CO2 performance at 8 bar was 10.66 mmol g–1 at 25 °C. The thermodynamics indicated the exothermic and spontaneous nature of the adsorption process, which was dominated by a physisorption mechanism. Furthermore, the CO2 uptake curves on a TGA analyzer were fitted with different kinetic models, and the fractional order model showed the best agreement with the experimental data. The recycling curve of SCS-700 exhibited excellent cyclic adsorption performance with no significant capacity loss even after ten adsorption–desorption cycles. It is suggested that this excellent CO2 uptake was due to the synergistic effect of the well-developed microporous structure and the oxidized sulfur-containing functional groups.

The modified iron porphyrins with weak ligand (PF6 –, BF4 –) were prepared by a gentle and cheap approach. The catalytic systems with modified iron porphyrins and 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]­PF6) were used in the catalytic oxidative removal of sulfur compounds from model oil under mild conditions. The effect of anionic axial ligand on catalytic oxdative desulfurization performance was investigated. Iron porphyrins with weak ligand exhibited higher desulfurization performance, and the catalytic ability of catalysts was FeIIITPP­(PF6) > FeIIITPP­(BF4) > FeIIITPPCl. A dual active model mechanism was proposed to illustrate this phenomenon of oxidative process. The system of FeIIITPP­(PF6) and [Bmim]­PF6 could be recycled for 6 times without evident decrease of desulfurization efficiency.

One-pot extractive and oxidative desulfurization of model oil in polyethylene glycol.