Nanosized NiO, CeO₂ and NiO-CeO₂ mixed oxides with different Ni/Ce molar ratios were prepared by the soft template method. All the samples were characterized by different techniques as to their chemical composition, structure, morphology and texture. On the catalysts submitted to the same reduction pretreatment adopted for the activity tests the surface basic properties and specific metal surface area were also determined. NiO and CeO₂ nanocrystals of about 4 nm in size were obtained, regardless of the Ni/Ce molar ratio. The Raman and X-ray photoelectron spectroscopy results proved the formation of defective sites at the NiO-CeO₂ interface, where Ni species are in strong interaction with the support. The microcalorimetric and Fourier transform infrared analyses of the reduced samples highlighted that, unlike metallic nickel, CeO₂ is able to effectively adsorb CO₂, forming carbonates and hydrogen carbonates. After reduction in H₂ at 400 °C for 1 h, the catalytic performance was studied in the CO and CO₂ co-methanation reaction. Catalytic tests were performed at atmospheric pressure and 300 °C, using CO/CO₂/H₂ molar compositions of 1/1/7 or 1/1/5, and space velocities equal to 72000 or 450000 cm³·h⁻¹·g_cat⁻¹. Whereas CO was almost completely hydrogenated in any investigated experimental conditions, CO₂ conversion was strongly affected by both the CO/CO₂/H₂ ratio and the space velocity. The faster and definitely preferred CO hydrogenation was explained in the light of the different mechanisms of CO and CO₂ methanation. On a selected sample, the influence of the reaction temperature and of a higher number of space velocity values, as well as the stability, were also studied. Provided that the Ni content is optimized, the NiCe system investigated was very promising, being highly active for the CO_x co-methanation reaction in a wide range of operating conditions and stable (up to 50 h) also when submitted to thermal stress.

采用软模板法制备了不同Ni / Ce摩尔比的纳米NiO，CeO ₂和NiO-CeO ₂混合氧化物。所有样品均通过不同技术对其化学组成，结构，形态和质地进行了表征。在用于活性测试的相同还原预处理催化剂上，还测定了其表面基本性能和比金属表面积。无论Ni / Ce的摩尔比如何，都可获得尺寸约为4nm的NiO和CeO ₂纳米晶体。拉曼和X射线光电子能谱结果证明在NiO-CeO ₂处形成缺陷部位界面，其中Ni物种与支持物强烈相互作用。还原样品的微量热分析和傅立叶变换红外分析结果表明，与金属镍不同，CeO ₂能够有效吸附CO ₂，形成碳酸盐和碳酸氢盐。在400°C下H ₂还原1 h后，研究了CO和CO ₂共甲烷化反应的催化性能。在大气压力和300°C下使用1/1/7或1/1/5的CO / CO ₂ / H ₂摩尔组成和空速等于72000或450000 cm ³ ·h ^-1 ·进行催化测试g_猫^-1。在任何研究的实验条件下，CO几乎都被氢化，而CO ₂转化率受CO / CO ₂ / H ₂比和空速的强烈影响。鉴于CO和CO ₂甲烷化的不同机理，解释了更快和绝对优选的CO加氢。在选定的样品上，还研究了反应温度和更高数量的空速值以及稳定性的影响。只要优化Ni含量，研究的NiCe系统就很有前景，对CO _x具有高活性 共甲烷化反应在宽范围的操作条件下也很稳定（长达50小时），即使受到热应力也是如此。