This work addresses the kinetics of the CO₂ hydrogenation to methanol over a Cu/CeO₂/ZrO₂ catalyst studied using single-site, dual-sites and three adsorption sites kinetic models. Physicochemical constraints and statistical indicators are used as tool for model discrimination. The best performing model is used to elucidate the reaction mechanism and the relative roles of the Cu-sites and oxygen vacancies. The results show that the dissociative adsorption of H₂ occurs on the Cu⁰ sites, while CO₂ is attracted to the oxygen vacancies created by the CeO₂-ZrO₂ solid solution. Then, the adsorbed H interacts preferentially with the carbon atom, favouring the so-called “formate” route. The CO formed via the r-WGS reaction could either desorb to the gas phase or react via hydrogenation to methanol. Analysis of the relative contributions of the CO₂ and CO hydrogenation (i.e. direct and indirect pathways, respectively) to the methanol synthesis reveals that the latter is in fact preferential at high temperatures (i.e. about 100% of methanol is produced from CO at 260 ⁰C and 30 bar), and it shows an optimum vs the H₂:CO₂ ratio (c.a. 7 at 200 ⁰C and 30 bar), which corresponds to the saturation of the Cu⁰ sites with H₂. Thus, this work provides an essential tool (i.e., kinetic model) for the design of reactors and processes based on novel catalysts, and importantly, it offers a deeper understanding of the reaction mechanism as basis for further catalyst development.

这项工作解决了使用单中心、双中心和三吸附中心动力学模型研究的 Cu/CeO ₂ /ZrO _{2催化剂上 CO 2加氢制甲醇的动力学。}物理化学约束和统计指标被用作模型识别的工具。最佳性能模型用于阐明反应机理以及 Cu 位点和氧空位的相对作用。结果表明，H ₂的解离吸附发生在Cu ⁰位点，而CO ₂被CeO ₂ -ZrO _{2产生的氧空位吸引。}实在的方法。然后，吸附的 H 优先与碳原子相互作用，有利于所谓的“甲酸盐”路线。通过 r-WGS 反应形成的 CO 可以解吸到气相中，也可以通过加氢反应生成甲醇。分析 CO ₂和 CO 加氢（即分别为直接和间接途径）对甲醇合成的相对贡献表明，后者实际上在高温下优先（即约 100% 的甲醇在 260 ⁰C 下由 CO 生产）和 30 bar），它显示了与 H ₂ :CO ₂比（ca 7 at 200 ⁰C 和 30 bar）的最佳值，这对应于 Cu ⁰位点与 H _{2的饱和度}. 因此，这项工作为基于新型催化剂的反应器和工艺设计提供了必不可少的工具（即动力学模型），更重要的是，它提供了对反应机理的更深入理解，作为进一步催化剂开发的基础。