The catalytic conversion of carbon dioxide to synthetic CH₄ was studied on five Ni/YSZ samples, with the same nickel loading (10 wt%) but different Ni particle size. The catalysts, prepared by different methods, were characterized combining morphological (BET, TEM), structural (XRD, in-operando XAS), electronic (XPS, in-operando XANES) analysis and H₂-TPR experiments. The results showed that catalytic activity and CH₄ selectivity depended on size and morphology of Ni particles, and that type and amount of deposited carbon strongly depended on Ni⁰ morphology. The kinetic measurements revealed that both H₂ and CO₂ reactants were activated on Ni sites, and that YSZ support was not directly involved in the reaction mechanism.

The most efficient catalyst was that prepared by wet impregnation with Ni(EDTA)²⁻ complex due to the high Ni⁰ dispersion.This catalyst showed low amount of carbon and remarkable stability over time on stream. In-operando XAS showed that it did not undergo deactivation by Ni⁰ → Ni²⁺ oxidation using high CO₂ concentration, thus it is applicable in dynamic conditions like those typical in the energy storage from renewable sources process.

在五个镍/ YSZ样品上研究了二氧化碳到合成CH ₄的催化转化，其中镍负载量相同（10 wt％），但镍粒度不同。通过形态分析（BET，TEM），结构分析（XRD，操作数内XAS），电子分析（XPS，操作数内XANES）和H ₂ -TPR实验，对用不同方法制备的催化剂进行了表征。结果表明，催化活性和CH ₄选择性取决于Ni颗粒的大小和形态，而沉积碳的类型和数量则强烈取决于Ni ⁰形态。动力学测量表明，H ₂和CO _2均 反应物在Ni位点上被激活，并且YSZ载体不直接参与反应机理。

最有效的催化剂是由于Ni ⁰的高分散性，通过用Ni（EDTA）²⁻络合物进行湿浸渍制备的催化剂，该催化剂显示出低的碳含量和长期的运行稳定性。In-operando XAS研究表明，它不会因使用高CO ₂浓度的Ni ⁰  →Ni ²⁺氧化而失活，因此它适用于动态条件，例如可再生资源过程中的典型能量存储。