共查询到19条相似文献,搜索用时 78 毫秒
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苯胺是重要的化工原料和合成中间体,通过硝基苯的催化还原反应可以方便地制备苯胺类化合物。多孔碳材料因其高比表面积、发达的孔隙结构和容易回收等特点在催化领域越来越受到重视,然而其应用受到自身活性位点缺乏和化学惰性的限制。杂原子掺杂可以增强碳材料的表面极性,调节电子结构,改善其催化性能,可作为硝基苯催化还原反应的有效催化剂。本文对近年来掺杂多孔碳材料在硝基苯催化还原反应中的研究进展进行了总结。本文概述了氮掺杂型多孔碳材料、共掺杂型多孔碳材料、负载贵金属的掺杂多孔碳材料和负载廉价金属的掺杂多孔碳材料这4种主要的掺杂多孔碳材料的制备方法,并详细介绍了不同掺杂多孔碳材料在催化硝基苯催化还原反应时的催化性能、可能的催化活性位点以及催化机理。最后,指出目前掺杂多孔碳材料催化硝基苯还原还需要解决反应选择性、催化剂催化活性和生产成本等问题,以生物质为前体,开发共掺杂型和二元双金属负载的掺杂多孔碳材料是未来的重要发展方向之一。 相似文献
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我国煤炭资源丰富,以煤为原料制备碳纳米管,可以实现煤炭资源的高效利用,减少环境污染,为煤炭行业的发展提供新途径。以煤基聚苯胺为碳氮源,分别以乙酸镍或柠檬酸铁为碳源热解催化剂,以二茂镍、乙酸镍或二茂铁为碳管生长催化剂,采用催化热解-化学气相沉积耦合法成功制备出了三种高石墨化程度的掺N碳微纳米管。并对其进行了SEM、TEM、XRD、Raman、XPS等结构测试和甲醇氧化电催化剂载体应用测试,结果发现:三种掺N碳微纳米管的微观形态多样,有直立管、弯曲管、竹节状管等。二茂镍和二茂铁适合生长长而直的碳管,乙酸镍适合生长短而弯的碳管。二茂镍和乙酸镍所长碳管收率相当,约为5.8%(质量);二茂铁所长碳管收率较高,为21.2%(质量)。N元素主要以石墨型N掺入三种碳微纳米管中,乙酸镍所长碳管的掺N量最高,为1.17%(质量),且表现出良好的电催化剂载体性能。 相似文献
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以酱香酒酒糟为碳源,磷酸氢二铵为氮-磷源和活化剂,采用直接物混-高温工艺一步碳化活化制备酒糟基多孔碳材料。通过BET、XRD、XPS、SEM、TEM等进行表征分析,考察了碳材料对Cr(Ⅵ)模拟废水的吸附性能。结果表明,当磷酸氢二铵和酒糟质量比为1、活化温度为800℃时,BC800-1的比表面积、总孔容和微孔容分别达到609.08 m2/g, 0.363 cm3/g和0.188 cm3/g,以微孔和小介孔为主,具有部分石墨化结构,表面N、P元素含量分别为3.28%和2.3%。BC800-1对Cr(Ⅵ)的吸附性能较好,在原始条件下最高吸附量为9.2 mg/g。 相似文献
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氮掺杂多孔碳(NPC)电极材料具有特殊的多孔结构,导致其比表面积高,化学稳定性好,同时电容性能良好,然而导电性差,能量密度低等因素也限制了其实际应用。以天然产物为碳源,经高温热解产生碳化残渣,将这些残渣经筛分,与氢氧化钾和三聚氰胺一起混合、研磨,然后再经过高温焙烧、洗涤、烘干后得到NPC样品。该样品外观为黑色粉末,在扫描电镜下观察其形貌呈现多孔状,氮元素含量达到6.45wt%。将NPC与乙炔黑、聚偏氟乙烯按8∶1∶1的质量比制成电极压片,可组装成对称型超级电容器。在两电极体系下,以6M KOH为电解液,通过恒电流充放电(GCD)和循环伏安(CV)测试表明:电流密度为0.1A/g时,组装的超级电容器的比电容达到145F/g,而且当功率密度为50W/kg时,能量密度可达到20Wh/kg。经1000次循环充放电后,其比电容仍然保持96.9%,库仑效率基本稳定在99%,说明NPC具有优良的电容特性和循环稳定性。 相似文献
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Yoriko Tanaka Masahiro Furuta Koichi Kuriyama Ryosuke Kuwabara Yukiko Katsuki Takeshi Kondo Akira Fujishima Kensuke Honda 《Electrochimica acta》2011,(3):1172
Nitrogen-doped hydrogenated amorphous carbon thin films (a-C:N:H, N-doped DLC) were synthesized with microwave-assisted plasma-enhanced chemical vapor deposition widely used for DLC coating such as the inner surface of PET bottles. The electrochemical properties of N-doped DLC surfaces that can be useful in the application as an electrochemical sensor were investigated. N-doped DLC was easily fabricated using the vapor of nitrogen contained hydrocarbon as carbon and nitrogen source. A N/C ratio of resulting N-doped DLC films was 0.08 and atomic ratio of sp3/sp2-bonded carbons was 25/75. The electrical resistivity and optical gap were 0.695 Ω cm and 0.38 eV, respectively. N-doped DLC thin film was found to be an ideal polarizable electrode material with physical stability and chemical inertness. The film has a wide working potential range over 3 V, low double-layer capacitance, and high resistance to electrochemically induced corrosion in strong acid media, which were the same level as those for boron-doped diamond (BDD). The charge transfer rates for the inorganic redox species, Fe2+/3+ and Fe(CN)64−/3− at N-doped DLC were sufficiently high. The redox reaction of Ce2+/3+ with standard potential higher than H2O/O2 were observed due to the wider potential window. At N-doped DLC, the change of the kinetics of Fe(CN)63−/4− by surface oxidation is different from that at BDD. The rate of Fe(CN)63−/4− was not varied before and after oxidative treatment on N-doped DLC includes sp2 carbons, which indicates high durability of the electrochemical activity against surface oxidation. 相似文献
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Mingdong Sun Zhengyun Bian Weiwei Cui Xiaolong Zhao Shu Dong Xuebin Ke Yu Zhou Jun Wang 《中国化学工程学报》2022,43(3):192-201
Heteroatom-doped carbon materials have demonstrated great potential in the electrochemical reduction reaction of CO2 (CO2RR) due to their versatile structure and function. However, rational structure control remains one challenge. In this work, we reported a unique carbon precursor of soft template-containing porous poly(ionic liquid) (PIL) that was directly synthesized via free-radical self-polymerization of ionic liquid monomer in a soft template route. Variation of the carbonization temperature in a direct pyrolysis process without any additive yielded a series of carbon materials with facile adjustable textural properties and N species. Significantly, the integration of soft-template in the PIL precursor led to the formation of hierarchical porous carbon material with a higher surface area and larger pore size than that from the template-free precursor. In CO2RR to CO, the champion catalyst gave a Faraday efficiency of 83.0% and a current density of 1.79 mA·cm-2 at -0.9 V vs. reversible hydrogen electrode (vs. RHE). The abundant graphite N species and hierarchical pore structure, especially the unique hierarchical small-/ultra-micropores were revealed to enable better CO2RR performance. 相似文献
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过量的磷流入水体易导致水体富营养化等环境问题。吸附法由于操作方便、经济高效等特点被广泛应用于水体磷酸盐的去除。有序多孔材料具有孔道规则,比表面积大,孔容大等特点,其作为载体可有效提高活性物种的分散性,从而提高吸附剂去除磷酸盐的效率。该文综述了基于不同有序多孔材料合成的吸附剂应用于水体磷酸盐去除的进展,主要包括有序多孔碳材料、有序多孔硅材料和金属有机框架。讨论了基于有序多孔材料吸附剂的磷酸盐吸附性能、主要吸附机制、影响因素及回收利用等。总结了基于有序多孔材料吸附剂吸附磷酸盐存在的问题,展望了其未来研究方向及应用前景。 相似文献
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过量的磷流入水体易导致水体富营养化等环境问题,吸附法由于操作方便、经济高效等特点被广泛应用于水体磷酸盐的去除。有序多孔材料具有孔道规则,比表面积大,孔容大等特点,其作为载体可有效提高活性物种的分散性,从而提高吸附剂吸附磷酸盐的效率。综述了基于不同有序多孔材料的吸附剂应用于水体磷酸盐去除的进展,主要包括有序多孔碳材料、有序多孔硅材料和金属有机框架。讨论了基于有序多孔材料吸附剂的磷酸盐吸附性能、主要吸附机理、影响因素及回收利用。总结了基于有序多孔材料吸附剂吸附磷酸盐存在的问题,展望了其未来研究方向及应用前景。 相似文献
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多孔炭材料具有较大的比表面积和发达的孔隙结构,是吸附有毒有害气体的关键材料,备受环境、化工、军事化学等领域的关注。多孔炭材料对有毒有害气体的吸附性能受气氛中水分子竞争吸附的影响,研究多孔炭材料对水分子的吸附行为是复杂环境下吸附分离有毒有害气体的基础,对改进多孔炭材料的表面官能团组成和孔结构具有重要的指导意义。基于此,本文综述了国内外关于水分子在多孔炭材料上吸附的机理、过程和影响因素,探讨了水分子作为示踪分子用于多孔炭材料结构表征的潜在可能,并对未来吸附理论的研究方向和指导新型吸附材料设计的应用前景进行展望。 相似文献