本研究是利用Z-scheme異質結構作為光觸媒還原二氧化碳形成一氧化碳以及碳氫化合物。本實驗成功利用水熱法將氧化亞銅修飾於二硫化錫表面，藉以形成Z-scheme異質結構，用以進行光催化二氧化碳還原反應。經由紫外光電子能譜儀鑑定兩材料的功函數藉以證明此異質結構為Z-scheme異質結構，此機制能有效減少電子電洞對的再結合，即能有效提升載子分離率，使更多的電子電洞能夠與水以及二氧化碳進行反應。於本研究中，探討以不同溫度修飾氧化亞銅在二硫化錫表面對於材料的結構、性質等等的影響。並利用X光光電子能譜儀探討經過光催化反應前後各個元素的價態變化，藉以探討Z-scheme異質結構對於反應前後氧化態的影響，可以發現於反應後氧化亞銅的二價銅的比例降低而錫的結合能向較高能量偏移，此現象顯示電子由二硫化錫傳遞至氧化亞銅並且符合Z-scheme異質結構的電子傳遞機制。光致激發光譜儀的量測結果顯示，將氧化亞銅修飾二硫化錫表面後，載子再結合導致的螢光放光強度大幅下降，顯示此異質結構能有效的提升載子分離，並結合氣相層析儀探討催化活性以及產物的變化，氧化亞銅修飾的二硫化錫主要產物為一氧化碳，產率為2.813 μmol h-1 g-1，對比修飾前的量子效率提升至兩倍，證實經由氧化亞銅修飾後，能有效提升電子電洞對的分離，減少載子複合的機率，並能有效提升光觸媒對二氧化碳還原的效率。

In this study, we successfully synthesized Cu2O/SnS2 Z-scheme heterostructure as a photocatalyst for CO2 reduction to produce CO and hydrocarbon. This study used a simple two-step hydrothermal process to synthesize Cu2O on the SnS2 nanoflower. This heterostructure forms a Z-scheme structure and it can efficiently improve the separation of electron-hole pairs and the results proved by Ultraviolet photoelectron spectroscopy. Due to the Z-scheme structure, the electron-hole pairs get a higher chance to react with reactants and improve the hydrocarbon production yield. In this study, we used X-ray diffraction and Raman spectrum to compare the crystal structure of Cu2O and SnS2 heterostructure synthesized by different hydrothermal temperatures. After the structure analysis, we used X-ray photoelectron spectroscopy to compare the catalysts before and after the photocatalytic reaction. The ratio of Cu+ increased and Sn4+ shifted to the higher binding energy. These results indicated that the Z-scheme structure induces photo-carrier transfer from SnS2 to Cu2O and suppresses the oxidation of Cu2O. From the photoluminescence results, the intensity of the Cu2O/SnS2 heterostructure dramatically decreased. The results indicate Cu2O/SnS2 Z-scheme heterostructure reduces the charge recombination. According to the gas chromatography results, the Cu2O/SnS2 heterostructure produced CO as the main product and the production yield reach 2.813 μmol h-1 g-1 after three hours of illumination. The quantum efficiency becomes twice as much as origin SnS2. The results proved that Cu2O decorated on the SnS2 nanoflower as a Z-scheme heterostructure reduces the chance of charge recombination and efficiently improves catalyst activity.

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