The development of dual functional material for cyclic CO2 capture and hydrogenation is of great significance for converting diluted CO2 into valuable fuels, but suffers from kinetic limitation and deactivation of adsorbent and catalyst. Herein, we engineered a series of RuNa/γ-Al2O3 materials, varying the size of ruthenium from single atoms to clusters/nanoparticles. The coordination environment and structure sensitivity of ruthenium were quantitatively investigated at atomic scale. Our findings reveal that the reduced Ru nanoparticles, approximately 7.1 nm in diameter with a Ru-Ru coordination number of 5.9, exhibit high methane formation activity and selectivity at 340 °C. The Ru-Na interfacial sites facilitate CO2 migration through a deoxygenation pathway, involving carbonate dissociation, carbonyl formation, and hydrogenation. In-situ experiments and theoretical calculations show that stable carbonyl intermediates on metallic Ru nanoparticles facilitate heterolytic C–O scission and C–H bonding, significantly lowering the energy barrier for activating stored CO2.

中文翻译：

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在协同 Ru-Na 界面处设计纳米颗粒结构，用于集成 CO2 捕获和加氢


开发用于循环 CO2 捕获和加氢的双功能材料对于将稀释的 CO2 转化为有价值的燃料具有重要意义，但存在动力学限制和吸附剂和催化剂失活的问题。在此，我们设计了一系列 RuNa/γ-Al2O3 材料，将钌的大小从单个原子变为团簇/纳米颗粒。在原子尺度上定量研究了钌的配位环境和结构敏感性。我们的研究结果表明，还原的 Ru 纳米颗粒直径约为 7.1 nm，Ru-Ru 配位数为 5.9，在 340 °C 时表现出高甲烷生成活性和选择性。 Ru-Na 界面位点促进 CO2 通过脱氧途径迁移，包括碳酸盐解离、羰基形成和氢化。原位实验和理论计算表明，金属 Ru 纳米颗粒上稳定的羰基中间体促进了异质溶解 C-O 切割和 C-H 键合，显著降低了活化储存 CO2 的能垒。