Funktionsmaterialien: von harten zu weichen porösen Netzwerken

Yang

2013

Chemistry A European J

This article describes the synthesis and functions of phosphine or phosphine oxide functionalized networks (PP-P or PP-PO; PP = porous polymer). These materials were predominantly microporous and exhibited high surface areas (S(BET): 1284 and 1353 m(2) g(-1) for PP-P and PP-PO, respectively), with high CO2 (2.46 and 3.83 mmol g(-1) for PP-P and PP-PO, respectively) uptake capacities. Pd nanoparticles can be simply incorporated into the functionalized networks (PP-P-Pd or PP-PO-Pd) through a facile one-step impregnation. A yield of 98 % was obtained in the Suzuki reaction between 1-chlorobenzene and p-tolylboronic acid with the PP-P-Pd system, which was higher than that obtained when PP-PO-Pd (53.2 %) or [Pd(PPh3)4] (38.2 %) was used as the catalyst. The superior catalytic ability of PP-P-Pd can be attributed to the structural features that incorporate triarylphosphine within a microporous structure.

Section: Introductionmentioning

confidence: 99%

Novel Functionalized Microporous Organic Networks Based on Triphenylphosphine

Yang

2013

Chemistry A European J

“…[14][15][16][17][18] Die Eigenschaften dieser Polymere kçnnen durch die Auswahl der Monomere an die jeweilige Anwendung angepasst werden, [14,[16][17][18][19] so z. [14][15][16][17][18] Die Eigenschaften dieser Polymere kçnnen durch die Auswahl der Monomere an die jeweilige Anwendung angepasst werden, [14,[16][17][18][19] so z.…”

unclassified

Ein Energiespeicherprinzip auf Basis bipolarer poröser Polymernetzwerke

et al. 2012

Energiegeladen: Mit dem Ziel der Entwicklung eines Energiespeicherprinzips, das eine zwei‐ bis dreimal höhere spezifische Energie liefert als herkömmliche Hochleistungsbatterien, wurden ungeordnete, poröse, kovalente Triazin‐Polymernetzwerke als Kathodenmaterial genutzt. Sie zeigen eine einzigartige Faraday‐Reaktion, da sie sowohl in n‐ als auch in p‐dotierter Form vorliegen können (siehe Bild).

“…In particular, traditional synthesis methods involving the carbonization of low-vapor-pressure polymeric precursors 19,21] or natural sources [20] have their respective drawbacks, which are mostly associated with cross-linking reactions that proceed with concomitant char formation or uncontrolled vaporization during high-temperature pyrolysis. [22] Conjugated microporous polymers (CMP) have received considerable research interest because of their 3D interlinked porous structure, large Brunauer-Emmett-Teller (BET) specific surface areas, and good chemical stability [23][24][25][26][27][28][29][30][31][32][33] with regard to potential applications for the selected adsorption of organic solvents [24] and gas adsorption. [25][26][27][28][29][30][31][32][33] More interestingly, the surface areas and pore volumes of the CMP could be easily tuned by using different monomers with various molecule lengths, making them ideal candidates for preparation of porous carbon.…”

mentioning

confidence: 99%

Conjugated Microporous Polymer‐Derived Porous Hard Carbon as High‐Rate Long‐Life Anode Materials for Lithium Ion Batteries

et al. 2013

The development of vehicles using alternative fuel sources, such as hybrid electric vehicles, plug-in hybrid electric vehicles, and electric vehicles, requires advanced rechargeable batteries. Lithium ion batteries (LIBs) are promising candidates because of their intrinsic high energy density, high power density, and long cycling life. [1][2][3][4] The further development of LIBs could satisfy more rigorous demands such as high specific capacity, high rate performance, and long cycling life for the anode material. Silicon-based anode materials, [5][6][7] transition metal oxides, [8][9][10] and tin-based materials [11][12][13] are anode materials with high specific capacities. But they all have poor cycling performance because of the huge volume changes during the charge-discharge cycles. Therefore, carbon-based anode materials are still the focus of application and research as anode materials for LIBs. Graphite is the conventional anode material for commercial LIBs. [14,15] However, its limited specific capacity, susceptibility to exfoliation by electrolytes, poor rate performance, and short cycling life do not meet the needs of rapidly developing markets for LIBs. Porous carbons are promising anode materials for LIBs because of their high specific surface areas (SSA) and interconnected nanopores that can provide effective diffusion pathways for lithium ions. In addition, porous carbons have a high specific capacity provided by the large amount of active sites, no intercalation-induced exfoliation, reasonable electrical conductivity provided by the well-interconnected carbon walls, and minimized volume change during lithium intercalation-de-intercalation.[16] Therefore, it is important to prepare porous carbons with improved porosity. So far, a number of porous carbons have been prepared by using different methods such as hard templating, [17][18][19] hydrothermal carbonization, [20] and KOH treatment. [21] In addition, good rate capability and high capacities have been achieved by using these porous carbons as anode materials in LIB systems. For carbon-based anode materials, previous studies have shown that large SSA, pore volume, and high porosity of the porous carbon facilitate the enhancement of the performance of LIBs.[17] In most cases, however, it is difficult to obtain a porous carbon that fulfills such multivariable performance requirements, especially when using traditional materials such a gelatin, [17] sucrose, [18] polyacrylonitrile, [19] biomass, [20] and polypyrrole, [21] as carbon source. In particular, traditional synthesis methods involving the carbonization of low-vapor-pressure polymeric precursors 19,21] or natural sources [20] have their respective drawbacks, which are mostly associated with cross-linking reactions that proceed with concomitant char formation or uncontrolled vaporization during high-temperature pyrolysis. [22] Conjugated microporous polymers (CMP) have received considerable research interest because of their 3D interlinked porous structure, large Brunauer-Emmett-Teller (BET...