探討石墨烯量子點修飾過渡金屬二硫族化合物之產氫反應

GQDs Decorated Transition Metal Dichalcogenides for Hydrogen Evolution Reaction

劉仕傑(Shih-Jie Liou)

指導教授 ： 蘇雲良

國立清華大學/理學院/物理學系/碩士(2020年)

摘要

近年來探討利用二維過渡金屬二硫化合物(TMDCs)之材料做產氫催化反應越來越熱門。為了提升產氫效果，有些文章討論在TMDCs之材料上摻雜金屬來讓產氫效果更好，又有些文章是改變TMDCs材料的結構來使催化點位變多進而提升產氫效率。現今，用簡單的Bottom-up方法製備石墨烯量子點(GQDs)或石墨烯(GO)已經是成熟的技術，利用控制有機前體檸檬酸(CA)的碳化程度來製備石墨烯量子點(GQDs)或石墨烯(GO)。本論文是利用石墨烯量子點(GQDs)修飾MoS2與WSe2這兩種不同的TMDCs材料後，探討這兩種複合材料之產氫效率。
論文分成兩部分，第一部分是用離子插層法製備出1T相與2H相的MoS2¬材料，再利用Bottom-up方式製程出GQDs來修飾1T相與2H相的MoS2。我們利用UV-vis , Raman spectroscopy, XRD, XPS等四種測量方式確認我們做出來的樣品為實驗所需。第二部分是利用常見的薄膜製程技術：化學氣相沉積法(CVD)長出WSe2薄膜，再用GQDs修飾WSe2。WSe2是用Raman spectroscopy, PL, AFM等量測技術來確認材料成分與長晶後的薄膜厚度。將兩種TMDCs材料與GQDs合成複合材料後，再用電化學的三電極系統研究兩樣複合材料之產氫效率。
第一部分的研究結果發現：1T相的MoS2產氫效果會比2H相來的好，且有經過GQDs修飾過的材料，也會提升其產氫效率。第二部分因為CVD是我們實驗室是新的技術，目前長晶技術還尚未成熟，從Raman spectroscopy, PL, AFM的量測數據可以得知我們還無法長出少層數之樣品，但已經確定可以從前驅物的粉末製造出WSe2的薄膜，要將WSe2長成少層甚至單層數的樣品是指日可待，不久的未來就可以把少層或單層數的WSe2經過GQDs修飾後去探討其複合材料之產氫效果。

關鍵字

二維材料 ； 過渡金屬二硫族化合物 ； 石墨烯量子點 ； 電化學產氫

並列摘要

Recently, two-dimensional transition metal dichalcogenides (TMDs) materials have been widely studied for their superior catalytic performance in hydrogen evolution reaction (HER). There are articles discussing enhanced HER efficiency due to metal ion doping. There are also articles about changing the structures of TMD material to increase the number of catalytic sites for improving HER efficiency. Nowadays, simple bottom-up method has become a mature technique to prepare graphene quantum dots (GQDs) or graphene oxide (GO) by tuning the carbonization degree of citric acid. In this thesis, we studied the HER activity of GQDs decorated molybdenum disulfide (MoS2) and tungsten diselenide (WSe2¬) composites.
The thesis is divided into two parts. The first part is about the preparation of 1T and 2H MoS2 by ion intercalation method and the decoration of MoS2 sample with GQDs. We have used UV-vis to measure the visible and ultraviolet light absorption rate of the materials, Raman spectroscopy and XRD to identify the crystal structures and XPS measurements to probe the valence states of the sample. The second part is about the preparation of WSe2 films by chemical vapor deposition (CVD) method and the decoration of WSe2 film with GQDs. Raman spectroscopy and photoluminescence were employed to characterize the samples. Atomic force microscopy (AFM) was used to observe the morphology of the samples and to measure their thickness. The HER catalytic activity of the samples was evaluated by using a three-electrode system.
The results of our measurements show that 1T-MoS2 has better HER efficiency than 2H-MoS2. With GQDs decorated on MoS2, the HER efficiency can be improved. The 1T-MoS2@GQDs composites has the best HER efficiency.

並列關鍵字

Two-dimensional materials ； Transition Metal Dichalcogenides ； GQDs ； Hydrogen Evolution Reaction

參考文獻

[1] Levna Chacko,1 Pankaj Kumar Rastogi,2 and P. M. Aneesh, ‟ Phase Engineering from 2H to 1T-MoS2 for Efficient Ammonia PL Sensor and Electrocatalyst for Hydrogen Evolution Reaction.” J. Electrochem. Soc. 166(8) H263-H271 (2019).

[2] Hongchao Li, Jianpeng Zou, Senlin Xie, Xian Leng, Di Gao, Hongzhi Yang,Xu Mao, ‟ WSe2 nanofilms grown on graphite as efficient electrodes for hydrogen evolution reactions.” J. Alloys Compd. 725 884-890 (2017).

[3] Sunil R. Kadam, Andrey N. Enyashin, Lothar Houben, Ronen Bar-Ziv and Maya Bar-Sadan, ‟Ni–WSe2 nanostructures as efficient catalysts for electrochemical hydrogen evolution reaction (HER) in acidic and alkaline media.” J. Mater. Chem. A, 1403-1416 (2019).

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