【摘要】：隨著化石燃料的日趨枯竭,開發(fā)可替換的新型能源己迫在眉睫。氫能是一種可循環(huán)再生的清潔綠色能源,己得到人們越來越多的關(guān)注,被認(rèn)為是未來的理想能源。但在氫能的開發(fā)使用過程中,氫氣的儲運問題限制了其廣泛應(yīng)用。在目前眾多的儲氫技術(shù)中,硼氫化鈉(NaBH4)儲氫材料具有儲氫量高、儲運方便、產(chǎn)氫純度高、反應(yīng)可控性強等優(yōu)點,成為研究者們近年來的研究熱點。廉價高效催化劑是NaBH4通過水解反應(yīng)制取氫氣這項技術(shù)的關(guān)鍵。目前已有的催化劑大部分受限于成本較高、循環(huán)穩(wěn)定性和反應(yīng)活性差等問題而無法實際應(yīng)用。因此,本文的重點是開發(fā)廉價、高反應(yīng)活性且長壽命的NaBH4制氫催化劑。本文將廢棄棉桿制備成活性炭以實現(xiàn)生物質(zhì)資源的合理化利用,并用其作為載體制成負(fù)載型鈷基制氫催化劑。通過將SEM、XRD、FTIR、ICP-OES等測試手段與催化產(chǎn)氫實驗結(jié)合的方式,系統(tǒng)地考察了活化條件對棉桿活性炭(CSAC)為載體的Co基催化劑催化性能和循環(huán)穩(wěn)定性的影響。研究結(jié)果表明：制備的棉桿活性炭適合作為載體負(fù)載催化劑,通過浸漬-化學(xué)還原法制備的Co-B/CSAC催化劑具有較高的催化活性�；钚蕴康淖罴鸦罨瘲l件是：活化溫度為500℃、活化時間為1 h、活化劑用量(mH3PO4/m棉桿)為0.75。Co-B/CSAC催化劑具備一定的循環(huán)穩(wěn)定性,在5次循環(huán)使用后,催化活性能保持初次活性的54%。本文考察了助劑摻雜對Co基制氫催化劑反應(yīng)活性的影響,確定了最適助劑和加入量。并選用最佳助劑Ce摻雜的多組分催化劑對其催化NaBH4水解反應(yīng)的動力學(xué)進行了研究。研究發(fā)現(xiàn)：Ce助劑的加入對催化劑反應(yīng)活性的提高有顯著作用,最佳質(zhì)量配比為Ce:Co=1:10。Co-Ce-B/CSAC催化劑的反應(yīng)活性隨NaOH濃度的增大而減小,不隨NaBH4濃度的變化而改變。得到此催化劑表觀水解制氫速率的動力學(xué)方程如下：rH2=2.88×109exp-6799.8/T(1+0.16[NaOH]0.9)本論文還應(yīng)用化學(xué)鍍法制備了Co-B/CSAC催化劑,考察了其制備條件對催化性能的影響,對化學(xué)鍍法和浸漬-化學(xué)還原法制備的Co-B/CSAC催化劑的反應(yīng)活性及穩(wěn)定性也進行了對比研究。結(jié)果表明：與浸漬-化學(xué)還原法相比,化學(xué)鍍法制備的催化劑具有更高的反應(yīng)活性和穩(wěn)定性。當(dāng)Pd用量為0.4 g·L-1、NaBH4用量為0.51 g、NaOH添加量為2g時,Co-B/CSAC催化劑表現(xiàn)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，

本文編號：2466106