We report one-step non-oxidative coupling of methane (CH4) to ethylene (C2H4) at atmospheric pressure and mild temperature (ca. 180–190 °C), by a combination of non-thermal plasma and a CuOx/CeO2 catalyst. The C2H4 selectivity gradually increases during an induction period. The corresponding spent catalysts at different stages were systematically characterized to disclose the evolution of the CuOx/CeO2 catalyst. During the induction period, the CuO/CeO2 catalyst was partially reduced to generate Cu+, Ce3+ and Ov species, which accompany the formation of Cu+-Ov-Ce3+ sites, as proven by XRD, HRTEM, XPS, Raman, EPR and H2-TPR. In addition, the C2H4 selectivity is proportional to the fraction of Cu+, Ce3+, Ov and Cu-O-Ce species, which indicates that Cu+-Ov-Ce3+ is the active site for non-oxidative coupling of CH4 to C2H4. Furthermore, in-situ FTIR results indicate that the Cu+-Ov-Ce3+ interface sites can promote dehydrogenation of CH3* (from CH4 plasma) to produce CH2* on the catalyst surface, which is the basic reason why CuOx/CeO2 acts as a catalyst in speeding up the non-oxidative coupling of CH4 for C2H4 production.

中文翻译：

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CuxO/CeO2 催化剂在温下甲烷与乙烯和氢气的等离子体驱动非氧化耦合


我们报道了在大气压和温和温度（约 180-190 °C）下，通过非热等离子体和 CuOx/CeO2 催化剂的组合，甲烷 （CH4） 与乙烯 （C2H4） 的一步非氧化偶联。C2H4 选择性在诱导期间逐渐增加。系统表征了不同阶段的相应废催化剂，以揭示 CuOx/CeO2 催化剂的演变。在诱导期间，CuO/CeO2 催化剂被部分还原以生成 Cu+、Ce3+ 和 Ov 物种，这些物质伴随着 Cu+-Ov-Ce3+ 位点的形成，正如 XRD、HRTEM、XPS、Raman、EPR 和 H2-TPR 所证明的那样。此外，C2H4 选择性与 Cu+、Ce3+、Ov 和 Cu-O-Ce 种类的分数成正比，这表明 Cu+-Ov-Ce3+ 是 CH4 与 C2H4 非氧化偶联的活性位点。此外，原位 FTIR 结果表明，Cu+-Ov-Ce3+ 界面位点可以促进 CH3*（来自 CH4 等离子体）的脱氢，从而在催化剂表面产生 CH2*，这就是 CuOx/CeO2 作为催化剂加速 CH4 非氧化偶联以产生 C2H4 的基本原因。