近年來由於石油儲備的降低，使得甲烷逐漸被認為是重要的化工原料。此外，水力壓裂技術的發展用於頁岩氣提取的發展也有效提高甲烷等低碳烷烴的供應。因此，將甲烷轉化成其他高附加價值的化學產品，如乙烯，將會帶來巨大的利益。然而，在甲烷的穩定的C-H鍵的活化是在轉換過程中一個具有挑戰性的任務。最近，在金屬氧化物表面的甲烷活化，被認為是直接轉換甲烷轉化成其他有價值的化學品的方法中，最具有成本效益的方法。但是，甲烷與許多金屬氧化物的相互作用非常弱，導致難以搜索能有效促進活化且合適的金屬氧化物催化劑。在先前的研究中，為甲烷在二氧化銥(IrO2）上的脫氫且直接轉化甲烷成乙烯的研究奠定了初步基礎。雖然，甲烷活化在IrO2表面具有低能障，但是催化劑的成本很高。為了設計出高效，低成本的催化劑，在這裡我們使用密度泛函理論（DFT）方法去計算在覆蓋一層二氧化銥的二氧化鈦 (TiO2)表面以及一個銥原子摻雜的二氧化鈦表面上的甲烷活化。同時我們也探討了，在一層二氧化銥覆蓋的二氧化鈦表面上的乙烷和乙烯形成的C-C偶合反應，並且還探討了在銥摻雜的二氧化鈦表面上甲醇形成的C-O偶合反應。在一層二氧化銥覆蓋的二氧化鈦表面上的甲烷脫氫反應中，計算所得的反應障礙為0.55電子伏特，這是比在該表面上的吸附能（-0.70電子伏特）低，因此，我們可以預期，甲烷轉化率在該表面上會很高。在另一方面，在銥摻雜的二氧化鈦脫氫表面，計算的反應障礙為0.65電子伏特，比吸附能（-0.57電子伏特）高，但如果我們控制實驗條件，甲烷轉化仍然是可能的。在一層二氧化銥覆蓋的二氧化鈦表面上的C-C偶合反應，其能障非常接近的純二氧化銥表面，這顯示，這樣設計的表面將會是對於甲烷直接轉化的高效催化劑。在銥摻雜的二氧化鈦表面上的C-O偶合反應，甲醇生成的能障比純IrO2表面的高，但它仍然是一個可能的反應。這些結果顯示，不僅一層IrO2，甚至只有一個銥原子，其活性仍然可以保持。

Methane is attracted as a chemical feedstock in recent years because of declining petroleum reserves. Additionally, the development of fracking technologies for the extraction of shale gas have efficiently increased the supply of methane and other light alkanes. Hence, the chemical conversion of methane into value-added chemical products such as ethylene would be enormous beneficial. However, the activation of the stable C–H bond in methane is a challenging task in the conversion process. Recently, methane activation on metal oxide surfaces is considered as a cost-effective method to convert methane directly into value-added chemicals. However, a very weak interaction of methane with many oxides leads to search for a suitable metal oxide catalyst which can efficiently promote the activation. The previous study on methane dehydrogenation on IrO2(110) provides an initial basis for the direct conversion of methane into ethylene under mild temperature conditions. Even though, methane activation on IrO2 surface has low energy barrier, the cost of catalyst design is still high. In order to design the efficient and low cost catalyst, here we investigated the effect of one IrO2 layer support on TiO2 (110) surface and one Iridium atom doped TiO2(110) surface for the methane activation by using density functional theory (DFT) methods. We also have investigated the C-C coupling of ethane and ethylene formation on the IrO2 layer supported TiO2 surface and also the investigated the C-O coupling of methanol formation on Ir-doped TiO2 surface. The calculated reaction barriers for CH4 dehydrogenation on IrO2/TiO2 is 0.55 eV, which is lower than the adsorption energy (-0.70 eV) on this surface, so, we can predict that methane conversion is possible on this surface. In the other hand, the calculated reaction barriers for CH4 dehydrogenation on Ir-doped TiO2 is 0.74 eV, is higher than the adsorption energy (-0.57 eV), but methane conversion is still possible if we control the experimental condition. For the C-C coupling reactions on IrO2/TiO2 surface, the energy barriers are very close to the values that of pure IrO2 surface, which indicate that this designed surface would be an efficient catalyst for the direct conversion of methane. For C-O coupling reaction on Ir-doped TiO2 surface, the energy barrier for methanol is higher than the value that of pure IrO2 surface, but it still a possible reaction. Those results shows that not only one layer IrO2, the activity still can remain even there is only one Ir atom.

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