石墨烯釕、鎳金屬奈米粒子複合物的合成鑑定與其在觸媒氫化反應與觸媒轉移氫化反應上之作用

Synthesis and characterization of ruthenium and nickel nanoparticles on graphene composites, and their application in catalytic hydrogenation and catalytic transfer hydrogenation reactions

李哲宇(Jer-Yeu Lee)

指導教授 ： 劉陵崗

國立臺灣大學/理學院/化學研究所/博士(2015年)

https://doi.org/10.6342/NTU.2015.00628

摘要

利用修飾於氧化石墨烯表面的咪錯鹽離子對官能基，來穩定釕金屬奈米粒子，所得到的複合物GO-IL-Ru，具有良好的化學催化潛力。複合物中釕金屬奈米粒子粒徑約30奈米，含量為1.6 %，經由XANE與EXAFS鑑定出其金屬氧化態為Ru0。複合物GO-IL-Ru於高壓氫氣環境之下，可以完整氫化苯分子至環己烷。石墨烯特有的π-π作用力使複合物在催化「帶有苯環官能基的目標反應物」時，可以加快反應速率。當以GO-IL-Ru催化苯乙烯進行氫化反應，但氫氣莫耳數少於苯乙烯的四倍時，反應易出現聚苯乙烯副產物；在上述反應中，額外加入自由基TEMPO時，可以抑制聚苯乙烯的產生，但氫化反應的效果亦變差。以此判斷GO-IL-Ru在進行觸媒氫化反應的過程中，可能產生自由基，啟動聚合反應的進行。複合物GO-IL-Ru除可用於觸媒氫化反應之外，亦適用於觸媒轉移氫化反應，對後者也有很好的效果。如利用微波加熱，可以加快反應進行，而達到綠色化學的目標。
將硝酸鎳於高溫下裂解，擔載在氧化石墨烯表面，生成之複合物rGO-NiO，含有具磁性的NiO奈米粒子，粒徑約26奈米，鎳含量為47 wt%。經由XPS與PXRD分析，確認其為NiO奈米結晶。複合物rGO-NiO亦具有進行觸媒轉移氫化反應的能力，尤以苯甲醛及其衍生化合物為然。

關鍵字

石墨烯 ； 金屬奈米粒子 ； 氫化反應

並列摘要

The main theme of thesis is on the synthesis and characterization of the graphene composite abbreviated as GO-IL-Ru, based on graphite oxide with additional functional groups of organic ionic trains. It contains Ru at 1.61 wt% level (by ICP-OES), and the oxidation state of Ru NPs is Ru0 (by XANES and EXAFS). GO-IL-Ru has been used as a catalyst in both the hydrogenation reactions and transfer hydrogenation reactions. The catalytic activity of GO-IL-Ru was very good at compounds with phenyl groups, but not at those containing electronegative substituents or heterocyclic rings. Moreover, under insufficient hydrogen supplies, polystyrene polymer was formed, paralled to the styrene hydrogenation. When the TEMPO radical was added in the reaction mixture, both hydrogenation products and polymerization products were decreased in yields. Microwave speed-up of the catalytic transfer hydrogenation reactions was experimentably found as expected.
Ni(NO3)2 could be thermally decomposed in the presence of rGO to form magnetic NiO NPs on rGO sheets. The rGO-NiO composite contains Ni at 46.9 wt% level (by ICP-OES), the oxidation state of Ni is NiII (by XPS and PXRD). The rGO-NiO composite also has the ability to catalyze the transfer hydrogenation reactions, especially benzadehyde and related compounds.

並列關鍵字

graphene ； metal nanoparticle ； hydrogenation

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