本文關(guān)鍵詞：Na-N-B-H和Na-Ca-B-H復(fù)合體系的制備及放氫性能研究　出處：《北京理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 氨基鈉 硼氫化鈉 氯化鈣 液相球磨 催化劑 復(fù)合材料 儲氫性能

【摘要】：氫能作為一種環(huán)境友好、儲量豐富、燃燒值高、可循環(huán)應(yīng)用的新型能源載體,得到廣泛研究,而儲氫技術(shù)是目前限制氫能有效應(yīng)用的關(guān)鍵技術(shù)瓶頸,近年來,堿金屬配位氫化物儲氫體系因其較高的理論儲氫量和較優(yōu)良的儲氫性能,引發(fā)了大批學(xué)者的關(guān)注,成為國內(nèi)外儲氫領(lǐng)域研究的熱點。本文在對國內(nèi)外堿金屬配位氫化物儲氫體系研究現(xiàn)狀和進展進行全面綜述的基礎(chǔ)上,采用液相球磨技術(shù),以NaNH2:NaBH4(2:1)為反應(yīng)物、環(huán)己烷為液相溶劑保護劑制備Na-N-B-H復(fù)合儲氫材料,并在其中添加非晶態(tài)Co-Ni-B催化劑以改善材料的放氫性能。通過TG-DTA、XRD、FT-IR、活化能計算(Achar微分法和Coats-Redfern積分法)等分析測試手段對復(fù)合產(chǎn)物進行表征分析,以復(fù)合材料的放氫反應(yīng)活化能、放氫分解溫度和釋氫量為主要評價指標,測試其放氫反應(yīng)動力學(xué)性能和熱力學(xué)性能,探討了復(fù)合材料中催化劑添加比例對Na-N-B-H儲氫材料放氫性能的影響,同時探索了由NaBH4和CaCl2通過液相球磨制備的新型Na-Ca-B-H復(fù)合材料的儲氫性能。研究表明,添加5wt%Co-Ni-B的復(fù)合材料,490℃內(nèi)總失重率達到5.05wt%,最接近理論儲氫量,并且主要生成了新相復(fù)合物Na3(NH2)2BH4,因此確定本實驗的催化劑最佳添加量為5wt%;對比添加5wt%催化劑和未添加催化劑的復(fù)合材料,前者起始放氫溫度80℃、最大放氫速率峰值溫度282.9℃和分解反應(yīng)活化能69.1 KJ?mol-1均比后者要低,并且材料總失重率低于理論儲氫量,說明放氫反應(yīng)過程中催化劑抑制了雜質(zhì)氣體氨氣的產(chǎn)生,提高了材料的放氫性能。同時研究表明,本實驗的熱解反應(yīng)機理為三維擴散機理,機理函數(shù)表達式為f???=?????]1)1/(1[)1(2/313/13/4?。探索由NaBH4和CaCl2通過液相球磨制備新型Ca基儲氫材料,并通過XRD、TG-DTA、活化能計算等分析方法確定了反應(yīng)物制備復(fù)合材料的最佳反應(yīng)比例為NaBH4:CaCl2(4:1),并研究了Na-Ca-B-H復(fù)合材料的儲氫性能,結(jié)果表明,該材料起始放氫溫度為145℃、最大放氫速率峰值溫度為435.9℃、分解反應(yīng)活化能為121.8KJ?mol-1,480℃內(nèi)總失重率為2.87wt%,熱解反應(yīng)機理為隨機成核和隨后生長機理,機理函數(shù)表達式為f???=?????)]1ln()[1(4/1?3。
[Abstract]:Hydrogen energy, as a new type of energy carrier with friendly environment, rich reserves, high combustion value and recyclable application, has been widely studied. Hydrogen storage technology is the key technology bottleneck to limit the effective application of hydrogen energy in recent years. Because of its high theoretical hydrogen storage capacity and excellent hydrogen storage performance, alkali metal coordination hydride storage system has attracted a large number of scholars' attention. It has become a hotspot in the field of hydrogen storage at home and abroad. On the basis of a comprehensive review of the research status and progress of alkali metal coordination hydride hydrogen storage system at home and abroad, liquid phase ball milling technology is adopted in this paper. Na-N-B-H composite hydrogen storage material was prepared by using NaNH2: NaBH4: 1) as reactant and cyclohexane as liquid phase solvent protection agent. The amorphous Co-Ni-B catalyst was added to the catalyst to improve the dehydrogenation performance of the material. The activation energy was calculated by Achar differential method and Coats-Redfern integration method. The decomposition temperature and amount of hydrogen release are the main evaluation indexes, and the kinetic and thermodynamic properties of the hydrogen release reaction are tested. The effect of catalyst ratio on the hydrogen release properties of Na-N-B-H hydrogen storage materials was investigated. At the same time, the hydrogen storage properties of new Na-Ca-B-H composites prepared by ball milling of NaBH4 and CaCl2 were investigated. The total weight loss rate of the composite material added with 5wt Co-Ni-B at 490 鈩，

本文編號：1435232