The effect of the Y zeolite framework composition (Si/Al ratio) on the catalytic performances of 15%Ni-based samples for the CO₂ methanation reaction was studied. Different USY commercial zeolites with global Si/Al ratios ranging from 3 to 38 were then impregnated with the same Ni content and deeply characterized, namely by ICP analysis, TGA-DSC, XRD, N₂ adsorption, CO₂ adsorption, H₂-TPR, DRS UV–Vis and TEM. Zeolites were also ion-exchanged with different compensating cations (Na⁺ and Cs⁺). It was observed that higher Si/Al ratio lead to lower affinity of the zeolites to water, lower basicity and also to the presence of mesopores able to locate some of the Ni particles. The catalytic performances were verified to be remarkably favoured by higher Si/Al ratios, regardless the compensating cation present on the zeolite supports. This could be explained by the lower surface affinity of high Si/Al ratio zeolites to the produced adsorbed water molecules, which should normally induce an inhibitory effect on the transformation process. Therefore, the effect of the hydrophobicity of the zeolites resulting from the lower Al content appears to be more preponderant for the rate of the reaction than the decrease of basicity (reported in the literature as a relevant factor for methanation). In addition, no sintering or loss of crystallinity was observed after the catalytic tests. Thus, this work clearly shows that important improvements on the catalytic performance of zeolites for the CO₂ methanation can be achieved by adjusting their properties, namely the Si/Al ratio.

研究了Y沸石骨架组成（Si / Al比）对15％Ni基样品催化CO ₂甲烷化反应性能的影响。然后以相同的Ni含量浸渍全球Si / Al比在3至38之间的USY商业沸石，并对它们进行深层表征，即通过ICP分析，TGA-DSC，XRD，N ₂吸附，CO ₂吸附，H ₂ -TPR ，DRS UV-Vis和TEM。沸石还与不同的补偿阳离子（Na ⁺和Cs ⁺）。观察到较高的Si / Al比导致沸石与水的亲和力降低，碱度降低，并且还导致能够定位一些Ni颗粒的中孔的存在。事实证明，无论沸石载体上存在的补偿阳离子如何，较高的Si / Al比都显着有利于催化性能。可以通过高Si / Al比沸石对所产生的吸附水分子的较低表面亲和力来解释，这通常应在转化过程中产生抑制作用。因此，由较低的Al含量引起的沸石疏水性的影响似乎比碱度的降低更有利于反应速率（在文献中报道为甲烷化的相关因素）。此外，催化试验后未观察到烧结或结晶度损失。因此，这项工作清楚地表明，沸石对CO催化性能的重要改进可以通过调节其性能即Si / Al比来实现₂甲烷化。