通过在橡胶基体中集成多种功能性橡胶颗粒(FRGs),构筑具有多相网络结构的阻尼橡胶材料.首先通过扫描电子显微镜(scanning electron microscopy,SEM)和原子力显微镜(atomic force microscopy,AFM)观察所制备集成材料的微观形貌,然后探究...通过在橡胶基体中集成多种功能性橡胶颗粒(FRGs),构筑具有多相网络结构的阻尼橡胶材料.首先通过扫描电子显微镜(scanning electron microscopy,SEM)和原子力显微镜(atomic force microscopy,AFM)观察所制备集成材料的微观形貌,然后探究了FRGs多种组合对橡胶样品的动态性能的影响.结果表明,基于FRGs集成的多组分样品呈典型的“海-岛”多相结构,在保持每种FRGs组分相对独立的黏弹特性的同时,通过有效的界面反应实现黏弹特性的集成.进一步地,通过调控FRGs的网络结构参数和相对含量实现了各组分损耗峰的有序组合,获得一种多相结构的宽温域阻尼橡胶材料,其在吸音降噪方面展现出较好的应用潜力.此外,该多相阻尼材料还兼具优异的力学性能和吸能减震能力.本文工作基于传统橡胶工业原料和共混工艺,提出了一种简单易行、可规模化生产的橡胶阻尼材料制备新策略,不涉及复杂合成与改性,为发展高性能橡胶阻尼材料提供了新思路.展开更多
Due to the advantages of high surface areas, large pore volumes and pore sizes, abundant nitrogen content that favored the metal-support interactions, N-doped ordered mesoporous carbons are regarded as a kind ...Due to the advantages of high surface areas, large pore volumes and pore sizes, abundant nitrogen content that favored the metal-support interactions, N-doped ordered mesoporous carbons are regarded as a kind of fascinating and potential support for the synthesis of effective supported cat-alysts. Here, a N-doped ordered mesoporous carbon with a high N content （9.58 wt%）, high surface area （417 m^2/g）, and three-dimensional cubic structure was synthesized successfully and used as an effective support for immobilizing Pt nanoparticles （NPs）. The positive effects of nitrogen on the metal particle size enabled ultrasmall Pt NPs （about 1.0 ± 0.5 nm） to be obtained. Moreover, most of the Pt NPs are homogeneously dispersed in the mesoporous channels. However, using the ordered mesoporous carbon without nitrogen as support, the particles were larger （4.4 ± 1.7 nm） and many Pt NPs were distributed on the external surface, demonstrating the important role of the nitrogen species. The obtained N-doped ordered mesoporous material supported catalyst showed excellent catalytic activity （conversion 100%） and selectivity （〉99%） in the hydrogenation of halogenated nitrobenzenes under mild conditions. These values are much higher than those achieved using a commercial Pt/C catalyst （conversion 89% and selectivity 90%）. This outstanding catalytic perfor-mance can be attributed to the synergetic effects of the mesoporous structure, N-functionalized support, and stabilized ultrasmall Pt NPs. Moreover, such supported catalyst also showed excellent catalytic performance in the hydrogenation of other halogenated nitrobenzenes and nitroarenes. In addition, the stability of the multifunctional catalyst was excellent and it could be reused more than 10 times without significant losses of activity and selectivity. Our results conclusively show that a N-doped carbon support enable the formation of ultrafine metal NPs and improve the reaction ac-tivity and selectivity.展开更多
Polymer membrane fuel cells represent important sustainable energy devices because their operation involves zero emissions and low temperatures and their components exhibit low toxicity. Among the various components o...Polymer membrane fuel cells represent important sustainable energy devices because their operation involves zero emissions and low temperatures and their components exhibit low toxicity. Among the various components of such cells, the electrocatalyst plays the vital role of enhancing the output power density and/or working lifetime. Over the past several decades, numerous strategies have been proposed to address the challenges of electrocatalyst activity and/or durability. Herein, we review the applications of polyelectrolytes in electrocatalysts, including the enhancement of both catalytic nanoparticles and support materials. The effects of polyelectrolytes with regard to controlling the size, composition and morphology of catalytic nanoparticles, as well as the modification of support materials were summarized. In addition, the future possibilities for the research and development of polyelectrolytes in the field of catalyst design and synthesis are discussed.展开更多
文摘通过在橡胶基体中集成多种功能性橡胶颗粒(FRGs),构筑具有多相网络结构的阻尼橡胶材料.首先通过扫描电子显微镜(scanning electron microscopy,SEM)和原子力显微镜(atomic force microscopy,AFM)观察所制备集成材料的微观形貌,然后探究了FRGs多种组合对橡胶样品的动态性能的影响.结果表明,基于FRGs集成的多组分样品呈典型的“海-岛”多相结构,在保持每种FRGs组分相对独立的黏弹特性的同时,通过有效的界面反应实现黏弹特性的集成.进一步地,通过调控FRGs的网络结构参数和相对含量实现了各组分损耗峰的有序组合,获得一种多相结构的宽温域阻尼橡胶材料,其在吸音降噪方面展现出较好的应用潜力.此外,该多相阻尼材料还兼具优异的力学性能和吸能减震能力.本文工作基于传统橡胶工业原料和共混工艺,提出了一种简单易行、可规模化生产的橡胶阻尼材料制备新策略,不涉及复杂合成与改性,为发展高性能橡胶阻尼材料提供了新思路.
基金supported by the National Natural Science Foundation of China(201573136,U1510105)the Scientific Research Start-up Funds of Shanxi University(RSC723)~~
文摘Due to the advantages of high surface areas, large pore volumes and pore sizes, abundant nitrogen content that favored the metal-support interactions, N-doped ordered mesoporous carbons are regarded as a kind of fascinating and potential support for the synthesis of effective supported cat-alysts. Here, a N-doped ordered mesoporous carbon with a high N content （9.58 wt%）, high surface area （417 m^2/g）, and three-dimensional cubic structure was synthesized successfully and used as an effective support for immobilizing Pt nanoparticles （NPs）. The positive effects of nitrogen on the metal particle size enabled ultrasmall Pt NPs （about 1.0 ± 0.5 nm） to be obtained. Moreover, most of the Pt NPs are homogeneously dispersed in the mesoporous channels. However, using the ordered mesoporous carbon without nitrogen as support, the particles were larger （4.4 ± 1.7 nm） and many Pt NPs were distributed on the external surface, demonstrating the important role of the nitrogen species. The obtained N-doped ordered mesoporous material supported catalyst showed excellent catalytic activity （conversion 100%） and selectivity （〉99%） in the hydrogenation of halogenated nitrobenzenes under mild conditions. These values are much higher than those achieved using a commercial Pt/C catalyst （conversion 89% and selectivity 90%）. This outstanding catalytic perfor-mance can be attributed to the synergetic effects of the mesoporous structure, N-functionalized support, and stabilized ultrasmall Pt NPs. Moreover, such supported catalyst also showed excellent catalytic performance in the hydrogenation of other halogenated nitrobenzenes and nitroarenes. In addition, the stability of the multifunctional catalyst was excellent and it could be reused more than 10 times without significant losses of activity and selectivity. Our results conclusively show that a N-doped carbon support enable the formation of ultrafine metal NPs and improve the reaction ac-tivity and selectivity.
基金supported by the National Natural Science Foundation of China(21276058,21433003)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(2014DX10)
文摘Polymer membrane fuel cells represent important sustainable energy devices because their operation involves zero emissions and low temperatures and their components exhibit low toxicity. Among the various components of such cells, the electrocatalyst plays the vital role of enhancing the output power density and/or working lifetime. Over the past several decades, numerous strategies have been proposed to address the challenges of electrocatalyst activity and/or durability. Herein, we review the applications of polyelectrolytes in electrocatalysts, including the enhancement of both catalytic nanoparticles and support materials. The effects of polyelectrolytes with regard to controlling the size, composition and morphology of catalytic nanoparticles, as well as the modification of support materials were summarized. In addition, the future possibilities for the research and development of polyelectrolytes in the field of catalyst design and synthesis are discussed.
