地表的二氧化碳濃度日益升高，對環境產生重大影響，若能有效將二氧化碳轉換成高價值之化學品，可產生正向循環。
本論文成功以熱蒸鍍與化學氣相沉積法成長二硫化鉬薄膜於二氧化矽與氧化鋁基板上，再藉由氫氣與氮氣電在二硫化鉬的製程中，本研究可以良好控制二硫化鉬薄膜厚度，且在材料分析顯示，製備之二硫化鉬薄膜在可見光有良好之吸收，常壓下對於二氧化碳分子亦相當靈敏。
在眾多的表面改質中，本研究選用不同載流氣體的低壓電漿進行表面處理，並利用光電子能譜進行材料分析。在氫氣的環境下，利用氫氣離子轟擊表面，可使表面產生硫空缺；而在氮氣的環境下，氮氣離子轟擊表面，氮原子可摻雜於觸媒表面作為受體，改變二硫化鉬之半導體特性，使其能階位置符合二氧化碳還原反應能階，以上兩種表面處理分別可提升約三倍的二氧化碳轉換效率。

Global carbon emissions from fossil fuel raising decades, it cause climate change. If we can convert CO2 into chemicals and apply to industrial, it could become a virtuous cycle.
We successfully fabricate the uniform molybdenum disulfide fully covered thin films on silicon dioxide and sapphire substrate. By using the thermal evaporation and chemical vapor deposition process, we can well control the thickness of MoS2. In material analysis, it shows good photoadsorption in visible light region, also have good photoresponse sensitivity to CO2 gas molecules.
Furthermore, we introduce the hydrogen and nitrogen plasma treatment for our thin film. Both could enhance the activity of catalyst in CO2 reduction reaction around three times higher than pristine MoS2 thin film.
From XPS result, hydrogen plasma treatment creates the sulfur vacancy on the thin film surface. In nitrogen plasma treatment, it shows nitrogen doping on the surface of the MoS2 thin films. By using the UPS and UV-Vis spectrum, we can identify the band structure. After nitrogen plasma treatment, it shows the band structure shift to lower potential and fit the reaction potential of CO2 reduction reaction, it’s due to the nitrogen on the surface acts as a p-type dopant in MoS2 thin film. It could become the mechanism of the enhancement in CO2 reduction reaction photocatalyst activity.

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