光响应载体负载的铁基和钴基催化剂的合成及光热催化费托合成反应性能

发布时间：2018-04-10 05:37

本文选题：费托合成　切入点：光热催化　出处：《内蒙古大学》2017年硕士论文

【摘要】：费托合成(FTS)是以合成气(CO+H_2)为原料在催化剂和适当的条件下合成以长链烷烃为主的清洁液体燃料过程,是应对当前日益凸显的能源危机的最有效途径之一。而光热费托合成是在传统热费托的基础上引入光源,研究光热驱动的费托合成反应。为打破传统ASF分布规律提供新思路,对于能源资源的清洁、高效利用具有深刻意义。论文选取半导体SiC和CoAl_2O_4作为光响应载体,Fe和Co作为热敏感活性组分制备了一系列双功能催化剂并在不同条件下进行了催化活性评价。主要得到了如下研究结果:(1)以在可见光区有吸收的非金属半导体SiC为载体制备了 15%Co/SiC催化剂,对其进行了热及光热条件下的催化活性测试,发现引入光源后CO的转化率升高,CH_4选择性降低,C5+选择性升高,C_2-C_4产物中烷烃比例上升,烯烃比例下降。说明光源的引入有利于CO转化和碳链增长。这与以非光活性Si02为载体光热催化的规律不同。(2)以CoAl_2O_4和CoAl_2O_4-A1_2O_3为载体,负载15%Co作为催化剂,分别进行了热及光热费托活性评价,结果发现引入光源后两种催化剂的活性变化规律相同。与热催化相比,CO转化率大幅提高,CH_4的选择性降低,C__(5+)选择性升高,C_2-C_4产物中烷烯比升高,说明引入光源有利于CO的转化和Co的还原。但是在相同反应条件下,15%Co/CoAl_2O_4-Al_2O_3催化剂的活性比15%Co/CoAl_2O_4高,因为CoAl_2O_4-Al_2O_3中存在界面效应。同时对15%Co/CoAl_2O_4-Al_2O_3催化剂在引入不同光源的条件下进行了活性测试,发现引入可见光时催化活性最高。(3)以Fe为热活性组分制备了 15%Fe/SiC催化剂,分别进行了热催化及光热催化活性测试,发现引入光源后CO的转化率提高,CO_2的选择性降低,C_(5+)选择性升高,C_2-C_4产物中烷烯比升高。在反应过程中生成的碳纳米纤维促进了反应的进行。
[Abstract]:FTS is a process of synthesizing clean liquid fuel with long chain alkanes as the main fuel under the condition of catalyst and suitable conditions. It is one of the most effective ways to deal with the energy crisis which is becoming more and more prominent at present.The photothermal Fischer synthesis is based on the traditional heat Fischer to introduce the light source to study the photothermal driven Fischer synthesis reaction.It is of great significance for clean and efficient utilization of energy resources to break the traditional ASF distribution rule.In this paper, a series of bifunctional catalysts were prepared using semiconductor SiC and CoAl_2O_4 as photo-response carriers, Fe and Co as heat-sensitive active components, and the catalytic activity was evaluated under different conditions.The main results are as follows: (1) the 15%Co/SiC catalyst was prepared on the support of non-metallic semiconductor SiC, which was absorbed in the visible light region, and its catalytic activity was tested under thermal and photothermal conditions.It is found that the conversion rate of CO increases with the introduction of light source; the selectivity of CHS _ 4 decreases; the selectivity of C _ 5 increases; the proportion of alkanes in C _ 2-C _ 4 products increases and the ratio of olefins decreases.The results show that the introduction of light source is beneficial to CO conversion and carbon chain growth.This is different from that of photothermal catalysis using non-photoactive Si02 as the carrier. The photothermal and photothermal Fischer-Tropsch activity were evaluated using CoAl_2O_4 and CoAl_2O_4-A1_2O_3 as supports and supported 15%Co as catalyst, respectively.The results showed that the activity of the two catalysts was the same when the light source was introduced.Compared with thermal catalysis, the conversion rate of CO is greatly increased. The selectivity of Ch _ 4 is reduced. (C _ S _ S _ (5)) the ratio of alkane to ene in C _ 2-C _ 4 products is increased, indicating that the introduction of light source is beneficial to the conversion of CO and the reduction of Co.But under the same reaction conditions, the activity of Co/ CoAl _ 2O _ 3 catalyst is higher than that of 15%Co/CoAl_2O_4 because of the interfacial effect in CoAl_2O_4-Al_2O_3.At the same time, the activity of 15%Co/CoAl_2O_4-Al_2O_3 catalyst was tested under the condition of introducing different light sources. It was found that the catalytic activity of 15%Co/CoAl_2O_4-Al_2O_3 catalyst was the highest when the visible light was introduced. (3) the 15% sic catalyst was prepared with Fe as the thermal active component.Thermal catalysis and photothermal catalytic activity tests were carried out respectively. It was found that the conversion rate of CO increased with the introduction of light source. The selectivity of CO _ 2 was decreased. (C _ S _ 5) the ratio of alkene to alkene in the products of C _ 2-C _ 4 was higher than that of C _ (2) C _ (4).The reaction was facilitated by carbon nanofibers generated during the reaction.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TQ529.2

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