生物质活性炭基钴系硼氢化钠制氢催化剂的研究
发布时间：2019-04-26 13:28
【摘要】：随着化石燃料的日趋枯竭,开发可替换的新型能源己迫在眉睫。氢能是一种可循环再生的清洁绿色能源,己得到人们越来越多的关注,被认为是未来的理想能源。但在氢能的开发使用过程中,氢气的储运问题限制了其广泛应用。在目前众多的储氢技术中,硼氢化钠(NaBH4)储氢材料具有储氢量高、储运方便、产氢纯度高、反应可控性强等优点,成为研究者们近年来的研究热点。廉价高效催化剂是NaBH4通过水解反应制取氢气这项技术的关键。目前已有的催化剂大部分受限于成本较高、循环稳定性和反应活性差等问题而无法实际应用。因此,本文的重点是开发廉价、高反应活性且长寿命的NaBH4制氢催化剂。本文将废弃棉杆制备成活性炭以实现生物质资源的合理化利用,并用其作为载体制成负载型钴基制氢催化剂。通过将SEM、XRD、FTIR、ICP-OES等测试手段与催化产氢实验结合的方式,系统地考察了活化条件对棉杆活性炭(CSAC)为载体的Co基催化剂催化性能和循环稳定性的影响。研究结果表明：制备的棉杆活性炭适合作为载体负载催化剂,通过浸渍-化学还原法制备的Co-B/CSAC催化剂具有较高的催化活性。活性炭的最佳活化条件是：活化温度为500℃、活化时间为1 h、活化剂用量(mH3PO4/m棉杆)为0.75。Co-B/CSAC催化剂具备一定的循环稳定性,在5次循环使用后,催化活性能保持初次活性的54%。本文考察了助剂掺杂对Co基制氢催化剂反应活性的影响,确定了最适助剂和加入量。并选用最佳助剂Ce掺杂的多组分催化剂对其催化NaBH4水解反应的动力学进行了研究。研究发现：Ce助剂的加入对催化剂反应活性的提高有显著作用,最佳质量配比为Ce:Co=1:10。Co-Ce-B/CSAC催化剂的反应活性随NaOH浓度的增大而减小,不随NaBH4浓度的变化而改变。得到此催化剂表观水解制氢速率的动力学方程如下：rH2=2.88×109exp-6799.8/T(1+0.16[NaOH]0.9)本论文还应用化学镀法制备了Co-B/CSAC催化剂,考察了其制备条件对催化性能的影响,对化学镀法和浸渍-化学还原法制备的Co-B/CSAC催化剂的反应活性及稳定性也进行了对比研究。结果表明：与浸渍-化学还原法相比,化学镀法制备的催化剂具有更高的反应活性和稳定性。当Pd用量为0.4 g·L-1、NaBH4用量为0.51 g、NaOH添加量为2g时,Co-B/CSAC催化剂表现出最佳的催化活性。
[Abstract]:With the depletion of fossil fuels, the development of alternative energy sources is imminent. Hydrogen energy is a kind of clean and green energy which can be recycled. It has been paid more and more attention and is regarded as the ideal energy in the future. However, in the development and use of hydrogen energy, the storage and transportation of hydrogen has limited its wide application. Among the current hydrogen storage technologies, sodium borohydride (NaBH4) hydrogen storage materials have the advantages of high hydrogen storage capacity, convenient storage and transportation, high hydrogen production purity and strong reaction controllability, which have become the research focus of researchers in recent years. Cheap and efficient catalyst is the key technology of NaBH4 to produce hydrogen by hydrolysis reaction. Most of the existing catalysts are limited by the problems of high cost, poor cycle stability and reaction activity, so they can not be applied in practice. Therefore, the focus of this paper is to develop cheap, highly reactive and long-life NaBH4 catalysts for hydrogen production. In this paper, the waste cotton stalk was prepared into activated carbon to realize the rational utilization of biomass resources, and the supported cobalt-based catalyst for hydrogen production was prepared by using it as a carrier. The effects of activation conditions on the catalytic performance and cycle stability of Co-based catalysts supported on cotton stalk activated carbon (CSAC) were systematically investigated by combining SEM,XRD,FTIR,ICP-OES and catalytic hydrogen production experiments. The results show that the Co-B/CSAC catalyst prepared by impregnation-chemical reduction method has higher catalytic activity than that prepared by impregnation-chemical reduction method. The optimum activation conditions of activated carbon are as follows: activation temperature is 500 鈩，
本文编号：2466106
[Abstract]:With the depletion of fossil fuels, the development of alternative energy sources is imminent. Hydrogen energy is a kind of clean and green energy which can be recycled. It has been paid more and more attention and is regarded as the ideal energy in the future. However, in the development and use of hydrogen energy, the storage and transportation of hydrogen has limited its wide application. Among the current hydrogen storage technologies, sodium borohydride (NaBH4) hydrogen storage materials have the advantages of high hydrogen storage capacity, convenient storage and transportation, high hydrogen production purity and strong reaction controllability, which have become the research focus of researchers in recent years. Cheap and efficient catalyst is the key technology of NaBH4 to produce hydrogen by hydrolysis reaction. Most of the existing catalysts are limited by the problems of high cost, poor cycle stability and reaction activity, so they can not be applied in practice. Therefore, the focus of this paper is to develop cheap, highly reactive and long-life NaBH4 catalysts for hydrogen production. In this paper, the waste cotton stalk was prepared into activated carbon to realize the rational utilization of biomass resources, and the supported cobalt-based catalyst for hydrogen production was prepared by using it as a carrier. The effects of activation conditions on the catalytic performance and cycle stability of Co-based catalysts supported on cotton stalk activated carbon (CSAC) were systematically investigated by combining SEM,XRD,FTIR,ICP-OES and catalytic hydrogen production experiments. The results show that the Co-B/CSAC catalyst prepared by impregnation-chemical reduction method has higher catalytic activity than that prepared by impregnation-chemical reduction method. The optimum activation conditions of activated carbon are as follows: activation temperature is 500 鈩，
本文编号：2466106
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