The NH3-assisted synthesis strategy from preceramic polymers provides tools to engineer the porosity of microporous SiCNO ceramics for potential applications in the fields of catalysis, gas adsorption and gas separation.

No abstract

Hard carbons derived from organic precursors glucose (G) and potato starch (PS) and composite materials derived from glucose blended with commercial preceramic polymers, namely polyorganosilazane (SiOC(N)/HC) and polyorganosiloxane (SiOC/HC) are synthesized and investigated with respect to their application as anode materials for Na-ion batteries. A strong correlation is found between the electrochemical performance and the porosity of the materials, as well as the elemental composition of the samples. Mesoporous hard carbon HCPS and the nonporous composite SiOC/HCG containing low amount of oxygen (<10 wt-%) present the highest reversible capacity of 262 mAhg−1 for HCPS and 201 mAhg−1 for SiOC/HCG and the best first cycle efficiency, namely 74% for HCPS and 65% for SiOC/HCG.

Carbon dioxide (CO 2 ) capture is regarded as one of the biggest challenges of the 21st century; therefore, intense research effort has been dedicated in the area of developing new materials for efficient CO 2 capture. Here, we report high CO 2 capture capacity in the low region of applied CO 2 pressures observed with ultramicroporous silicon nitride-based material. The latter is synthesized by a facile one-step NH 3 -assisted thermolysis of a polysilazane. Our newly developed material for CO 2 capture has the following outstanding properties: (i) one of the highest CO 2 capture capacities per surface area of micropores, with a CO 2 uptake of 2.35 mmol g À1 at 273 K and 1 bar (ii) a low isosteric heat of adsorption (27.6 kJ mol À1 ), which is independent from the fractional surface coverage of CO 2 . Furthermore, we demonstrate that the pore size plays a crucial role in elevating the CO 2 adsorption capacity, surpassing the effect of Brunauer-Emmett-Teller specific surface area.

No abstract