Lithium orthosilicate (Li₄SiO₄) represents a potential class of high-temperature sorbents for CO₂ capture in power plants and sorption enhanced methane reforming to produce H₂. However, conventional wisdom suggests that pure Li₄SiO₄ should have extremely slow sorption kinetics at realistic low CO₂ concentrations. Here, we report the opposite result: using a simple and cost-effective glucose-based mild combustion procedure, an unusually efficient and pure form of Li₄SiO₄ (MC-0.6) was synthesized to achieve a maximum uptake capacity of 35.0 wt.% at 580 °C for CO₂ concentrations under 15 vol.% and maintained this capacity over multiple cycles. The characterization results showed that highly porous nano-agglomerate-like (50-100 nm) morphologies were apparent and ensured a rapid surface-sorption of CO₂. In this process, a macroporous nano-sized Li₂SiO₃ cover on the melt layer of Li₂CO₃ was identified for the first time. This special structure appeared to accelerate the transportation of CO₂ and the diffusion of Li⁺ and O^2- through a molten layer enhancing contact with CO₂. Thus, the sample MC-0.6 reduced both the surface-sorption and diffusion kinetics dependence on low CO₂ concentrations. Rather than use traditional approaches (controlled morphologies combined with doping), we have demonstrated that the slow kinetics can be overcome simply by a controlled morphologies strategy, which opens up a new direction for the synthesis of high-performance Li₄SiO₄ sorbents.

原硅酸锂（Li ₄ SiO ₄）代表了一类潜在的高温吸附剂，用于发电厂中的CO ₂捕集和增强甲烷重整以产生H _2的吸附。然而，传统观点认为，纯Li ₄ SiO ₄在现实的低CO ₂浓度下应具有极慢的吸附动力学。在这里，我们报告相反的结果：使用简单且经济高效的基于葡萄糖的轻度燃烧程序，合成了一种异常有效且纯净的Li ₄ SiO ₄（MC-0.6）形式，最大吸收量为35.0 wt％。 CO ₂在580°C时的百分比浓度低于15％（体积），并在多个循环中保持该容量。表征结果表明，高度多孔的纳米团状样（50-100 nm）形态是明显的，并确保了CO ₂的快速表面吸附。在此过程中，首次确定了在Li ₂ CO ₃熔体层上覆盖的大孔纳米级Li ₂ SiO ₃。这种特殊的结构似乎促进了CO ₂的运输以及Li ⁺和O ²穿过熔融层的扩散，从而增强了与CO _2的接触。。因此，样品MC-0.6降低了对低CO ₂浓度的表面吸附和扩散动力学。与使用传统方法（控制形态与掺杂相结合）相比，我们已经证明了慢速动力学可以简单地通过控制形态策略来克服，这为合成高性能Li ₄ SiO ₄吸附剂开辟了新的方向。