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Selective Oxidation of Methane to Methanol over Ceria-Zirconia Supported Mono and Bimetallic Transition Metal Oxide Catalysts
ChemCatChem ( IF 3.8 ) Pub Date : 2021-03-16 , DOI: 10.1002/cctc.202100268 Yimeng Lyu 1 , Jennifer Jocz 1 , Rui Xu 1 , Olivia Williams 1 , Carsten Sievers 2
ChemCatChem ( IF 3.8 ) Pub Date : 2021-03-16 , DOI: 10.1002/cctc.202100268 Yimeng Lyu 1 , Jennifer Jocz 1 , Rui Xu 1 , Olivia Williams 1 , Carsten Sievers 2
Affiliation
Several ceria-zirconia supported mono and bi-metallic transition metal oxide clusters containing Fe, Cu, and Ni are synthesized by dry impregnation. Through XRD, H2-TPR, NH3-TPD, pyridine adsorption followed by FTIR spectroscopy and XAS, the well-dispersed nature of the transition metal oxide clusters is revealed, and the Lewis acidity of the catalysts is assessed. In-situ FTIR spectroscopy is used to monitor the methane activation on catalyst surfaces. All catalysts activate methane at 250 °C forming methyl, alkyl, and methoxy species on the catalyst surface. By co-feeding steam and oxygen together with methane, continuous direct oxidation of methane to methanol can be achieved, with the complete oxidation to CO2 as the other reaction path. Methoxy species are found to be a key intermediate for methanol production. Lowering the methane conversion improves the methanol selectivity. By extrapolation, it is estimated that methanol selectivity close to unity can be achieved below a threshold of methane conversion at about 0.002 %. The formation of CuO and NiO mixed metal oxides produces stronger Lewis acid sites and yields higher methanol selectivity.
中文翻译:
在氧化铈-氧化锆负载的单金属和双金属过渡金属氧化物催化剂上选择性氧化甲烷为甲醇
通过干浸渍法合成了几种含 Fe、Cu 和 Ni 的氧化铈-氧化锆负载的单金属和双金属过渡金属氧化物簇。通过XRD、H 2 -TPR、NH 3 -TPD、吡啶吸附以及FTIR光谱和XAS,揭示了过渡金属氧化物簇的良好分散性质,并评估了催化剂的路易斯酸度。原位 FTIR 光谱用于监测催化剂表面的甲烷活化。所有催化剂都在 250 °C 下活化甲烷,在催化剂表面形成甲基、烷基和甲氧基物质。通过将蒸汽和氧气与甲烷共同进料,可实现甲烷连续直接氧化为甲醇,并完全氧化为CO 2作为另一个反应路径。发现甲氧基物质是甲醇生产的关键中间体。降低甲烷转化率可提高甲醇选择性。通过外推,估计在低于约 0.002% 的甲烷转化阈值时,甲醇选择性接近于 1。CuO 和 NiO 混合金属氧化物的形成产生更强的路易斯酸位点并产生更高的甲醇选择性。
更新日期:2021-03-16
中文翻译:
在氧化铈-氧化锆负载的单金属和双金属过渡金属氧化物催化剂上选择性氧化甲烷为甲醇
通过干浸渍法合成了几种含 Fe、Cu 和 Ni 的氧化铈-氧化锆负载的单金属和双金属过渡金属氧化物簇。通过XRD、H 2 -TPR、NH 3 -TPD、吡啶吸附以及FTIR光谱和XAS,揭示了过渡金属氧化物簇的良好分散性质,并评估了催化剂的路易斯酸度。原位 FTIR 光谱用于监测催化剂表面的甲烷活化。所有催化剂都在 250 °C 下活化甲烷,在催化剂表面形成甲基、烷基和甲氧基物质。通过将蒸汽和氧气与甲烷共同进料,可实现甲烷连续直接氧化为甲醇,并完全氧化为CO 2作为另一个反应路径。发现甲氧基物质是甲醇生产的关键中间体。降低甲烷转化率可提高甲醇选择性。通过外推,估计在低于约 0.002% 的甲烷转化阈值时,甲醇选择性接近于 1。CuO 和 NiO 混合金属氧化物的形成产生更强的路易斯酸位点并产生更高的甲醇选择性。