The Ni/ZrO₂ catalyst doped with Ca and Ni/ZrO₂ were employed in the CO₂ methanation, a reaction which will possibly be used for storing intermittent energy in the future. The catalysts were characterized by X-ray photoelectron spectroscopy (XPS, reduction in situ), X-ray diffraction (XRD, reduction in situ and Rietveld refinement), electron paramagnetic resonance (EPR), temperature-programmed surface reaction, cyclohexane dehydrogenation model reaction, temperature-programmed desorption of CO₂ and chemical analysis. The catalytic behavior of these catalysts in the CO₂ methanation was analyzed employing a conventional catalytic test. Adding Ca to Ni/ZrO₂, the metallic surface area did not change whereas the CO₂ consumption rate almost tripled. The XRD, XPS and EPR analyses showed that Ca⁺² but also some Ni²⁺ are on the ZrO₂ surface lattice of the Ni/CaZrO₂ catalyst. These cations form pairs which are composed of oxygen vacancies and coordinatively unsaturated sites (cus). By increasing the number of these pairs, the CO₂ methanation rate increases. Moreover, the number of active sites of the CO₂ methanation rate limiting step (CO and/or formate species decomposition, rls) is enhanced as well, showing that the rls occurs on the vacancies-cus sites pairs.

掺有Ca和Ni / ZrO ₂的Ni / ZrO ₂催化剂用于CO ₂甲烷化，该反应将来可能会用于存储间歇性能量。通过X射线光电子能谱（XPS，原位还原），X射线衍射（XRD，原位还原和Rietveld精制），电子顺磁共振（EPR），程序升温表面反应，环己烷脱氢模型反应对催化剂进行了表征。，程序升温的CO ₂解吸和化学分析。使用常规催化试验分析了这些催化剂在CO ₂甲烷化中的催化行为。向Ni / ZrO中添加Ca_{如图2所示}，金属表面积没有变化，而CO ₂消耗率几乎增加了两倍。XRD，XPS和EPR分析表明，Ni / CaZrO ₂催化剂的ZrO ₂表面晶格上有Ca ⁺²以及一些Ni ²⁺。这些阳离子形成由氧空位和配位不饱和位点（cus）组成的对。通过增加这些对的数目，CO ₂甲烷化率增加。此外，CO ₂甲烷化率限制步骤的活性位点数目（CO和/或甲酸盐种类分解，rls）也增加了，表明rls出现在空位-cus位点对上。