Optimization of supported heterogeneous catalysts requires a careful control of their synthesis conditions and in particular of the metal impregnation step. This paper presents a theoretical and experimental study of both dry and diffusional impregnation of Ni/γ-Al₂O₃ catalysts. The advanced characterization technique Magnetic Resonance Imaging was used to monitor in-situ the impregnation step, which provided the necessary information to develop the model. The model accurately describes the active phase distribution during impregnation by taking into account capillarity (in the case of dry impregnation), diffusion in the fluid phase and adsorption/desorption phenomena. It was demonstrated that the adsorption of nickel ions on the alumina surface is extremely fast, favoring the removal of metal ions from the fluid phase. As a consequence, the limiting step of impregnation is the diffusion of nickel ions in the fluid phase. A good agreement between experimental and simulated results was achieved by adjusting only two parameters, namely total concentration of the active sites and adsorption equilibrium constant. By neglecting capillary action and using the same optimized parameters, the model also allowed describing diffusional impregnation, which illustrates its robustness. This model can predict the distribution of the active phase in the support as a function of the impregnation conditions and can therefore be applied as a new tool to optimize the impregnation step of heterogeneous catalysts.

负载型非均相催化剂的优化需要仔细控制其合成条件，尤其是金属浸渍步骤。本文呈现两个干燥和Ni /扩散的浸渍的理论和实验研究的γ-Al ₂ ö ₃催化剂。先进的表征技术“磁共振成像”被用于原位监测浸渍步骤，这为开发模型提供了必要的信息。该模型通过考虑毛细作用（在干式浸渍的情况下），液相中的扩散以及吸附/解吸现象来精确描述浸渍过程中的活性相分布。结果表明，镍离子在氧化铝表面的吸附速度非常快，有利于从液相中去除金属离子。结果，浸渍的限制步骤是镍离子在液相中的扩散。通过仅调节两个参数，即活性位点的总浓度和吸附平衡常数，可以在实验结果和模拟结果之间取得良好的一致性。通过忽略毛细管作用并使用相同的优化参数，该模型还允许描述扩散浸渍，这说明了其耐用性。该模型可以根据浸渍条件预测载体中活性相的分布，因此可以用作优化非均相催化剂浸渍步骤的新工具。