CeO₂ nanorods (CeO₂-nrs), CeO₂ nanocubes (CeO₂-ncs) and CeO₂ nanopolyhedrons (CeO₂-nps) were prepared by hydrothermal method and then NiO crystallites were deposited on these supports by precipitation-deposition, respectively. The physic-chemical properties of Ni/CeO₂ catalysts were characterized and performances for carbon dioxide methanation reaction were tested. The Ni/CeO₂-nrs sample shows well metal dispersion and high concentration of oxygen vacancy, which leads to the high catalytic activity for CO₂ methanation. Especially at 300 °C, the CO₂ conversion could reach 60%. Further analysis reveals that the content of oxygen vacancy has a positive correlation with the surface area of catalyst. The largest surface area results in the most of oxygen vacancy on the Ni/CeO₂-nrs catalyst, and then a large amount of CO₂ could be activated at low temperatures. Meanwhile, large surface area facilitates the dispersion of active metals, and improves the degree of H₂ activation. The combined effect results in the promotion of catalytic activity for CO₂ methanation at low temperatures.

Graphic Abstract

CeO₂ nanorods (CeO₂-nrs), CeO₂ nanocubes (CeO₂-ncs) and CeO₂ nanopolyhedrons (CeO₂-nps) supported Ni catalysts were prepared. These catalysts ware tested for CO₂ methanation and further characterized by BET, XPS, TEM, H₂-TPR and TPD. The results showed that the content of oxygen vacancy has positive correlation with the specific surface area of catalyst.

中文翻译：

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在 Ni/CeO2 催化剂上增强 CO2 甲烷化的低温活性

的CeO ₂纳米棒（的CeO _2个-NRS）的CeO ₂纳米立方体（的CeO _2个-NCS）和的CeO ₂ nanopolyhedrons（的CeO _2个-nps）通过水热法合成，然后氧化镍微晶通过沉淀沉积，分别沉积在这些载体上。表征了Ni/CeO ₂催化剂的理化性质并测试了二氧化碳甲烷化反应的性能。Ni/CeO ₂ -nrs 样品显示出良好的金属分散性和高浓度的氧空位，这导致对 CO ₂甲烷化的高催化活性。特别是在300°C时，CO ₂转化率可达60%。进一步分析表明，氧空位的含量与催化剂的表面积呈正相关。最大的表面积导致Ni/CeO ₂ -nrs 催化剂上的氧空位最多，然后大量的CO ₂可以在低温下活化。同时，大的表面积有利于活性金属的分散，提高H _{2 的}活化程度。综合作用导致在低温下促进CO ₂甲烷化的催化活性。

图形摘要

的CeO ₂纳米棒（的CeO _2个-NRS）的CeO ₂纳米立方体（的CeO _2个-NCS）和的CeO ₂ nanopolyhedrons（的CeO _2个-nps）支持的制备镍催化剂。这些催化剂对CO ₂甲烷化进行了测试，并通过BET、XPS、TEM、H ₂ -TPR 和TPD进一步表征。结果表明，氧空位的含量与催化剂的比表面积呈正相关。