Influence of acid treatments on the activity of carbon nanotube-supported catalysts
Influence of acid treatments on the activity of carbon nanotube-supported catalysts
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DOI：
10.1016/s0008-6223(02)00450-5
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发表时间：
2003-12
期刊：
影响因子：
10.9
通讯作者：
Chunhua Li;K. Yao;Ji Liang
中科院分区：
文献类型：
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作者：
Chunhua Li;K. Yao;Ji Liang
催化过程通常用于化学催化剂[6]。为了研究在碳纳米管合成中催化剂主要起作用的工程中，碳纳米管载体的酸性对催化剂性能的影响，提高催化剂的合成速率和控制催化剂的选择性，涉及催化剂的化学反应。在实际应用中，所制备的纳米管（样品1）和催化剂的负载通常位于载体上，该载体用于酸处理的纳米管（样品2）已用于负载、分散催化元素和改善丙烯的催化分解。CNT支撑件具有机械强度。如今人们已经广泛认识到，酸处理如下：碳纳米管首先是载体，可能会影响催化活性。众所周知，在浓氢氟酸中浸泡24 h以使碳材料可用作催化剂载体并消除载体上的杂质，然后在提供无与伦比的灵活性的条件下回流浓硫酸1 h以定制催化剂性能[7]，用蒸馏水洗涤以满足特定需求[1]。碳纳米管（CNTs），作为新的水最多中和，然后干燥。一种碳材料，具有适当的孔径，通过有利于最大金属分散的催化剂将金属氧化物引入到CNT的表面上[2]。共沉淀法。我们采用硝酸镍和其特殊而稳定的结构特性以及吗啉-硝酸铝作为金属前驱体，戈伊铵作为催化剂的载体材料，碳酸盐作为沉淀剂。碳的重量比[3-5]。特别是它们的表面性质可以通过改性纳米管、碳酸铵、硝酸镍和通过不同的处理来满足特殊的需要。硝酸铝为1：3：3：1。碳纳米管分散在碳酸铵溶液中，但这些处理对碳酸铵溶液的性质有何影响，那么负载催化剂的混合溶液就很少有报道。在此加入硝酸镍和硝酸铝进行交流，在快速搅拌过程中对经酸处理的碳纳米管进行逐滴沉淀的影响。催化剂的沉淀活性在其上进行测试，用于合成，过滤并洗涤数次并干燥。讨论了碳纳米管的制备方法.预催化剂在600 ℃下煅烧4 h。用作催化剂载体的碳纳米管是氮气流。将不同处理的碳纳米管负载的催化剂用于催化合成碳纳米管。
Catalytic processes are commonly used in chemical diatomite catalysts [6]. In order to study the influence of engineering in which the catalyst mainly plays a role of the acidity of the CNT support on the catalytic properties increasing the rate and controlling the selectivity of the of catalysts in the synthesis of carbon nanotubes, catalysts chemical reactions involved. In practical application, the supported by as-prepared nanotubes (sample 1) and by catalyst is usually located on a support, which is used for acid-treated nanotubes (sample 2) have been used in the loading, dispersing catalytic element (s), and improving catalytic decomposition of propylene. The CNT support is mechanical strength. Today it has been widely realized that acid-treated as follows: the carbon nanotubes are first a support may affect catalytic activity. It is known that doused in concentrated hydrofluoric acid for 24 h to carbon materials can be used as a catalyst support and eliminate the diatomite support, and are then refluxed in offer unparalleled flexibility in tailoring catalyst properties concentrated sulfuric acid for 1 h [7], washed with distilled to specific needs [1]. Carbon nanotubes (CNTs), as a new water up to neutralization, and then dried. type of carbon material, have appropriate pore-size dis- Metal oxide is introduced onto the surface of CNTs by a tribution favoring maximum metallic dispersion [2]. Their co-precipitation method. We use nickel nitrate and special and steady structural characteristics and morpholo- aluminum nitrate as metal precursors, and ammonium gy are quite suitable for use as catalytic support materials carbonate as precipitant. The weight ratio of carbon [3–5]. Especially, their surface properties can be modified nanotube, ammonium carbonate, nickel nitrate and through different treatments to satisfy special needs. aluminum nitrate is 1: 3: 3: 1. CNTs are dispersed in the However, how these treatments affect the properties of the ammonium carbonate solution, then the mixed solution of catalysts supported has rarely been reported. In this nickel nitrate and aluminum nitrate is added to the communication the influence of acid-treated CNTs on the precipitant dropwise during rapid stirring. The precipitate activityofthecatalystsupportedonthem, forthesynthesis is filtered and washed several times and dried. The of more carbon nanotubes, is discussed. preliminary catalyst is calcined at 600 8C for 4 h under a The carbon nanotubes used as catalyst supports were nitrogen flow. produced by catalytic decomposition of propane over Ni/ The catalysts supported by CNTs treated differently are employed in the catalytic synthesis of carbon nanotubes.