2024年2月常州大学低碳清洁能源与安全高效燃烧科研团队孙运兰教授课题组2021级硕士研究生罗光权在Ceramics International期刊发表了题为“Enhancement of CO₂ adsorption performance and widening of adsorption temperature window by co-doping different valence state metals on the Li₄SiO₄ (010) surface”的研究论文。

Li₄SiO₄因其较高的CO₂理论吸附量和良好的稳定性能在CO₂捕集领域有着很好的应用前景。本文通过密度泛函理论（DFT）和实验手段相结合的方式，深入研究了Li₄SiO₄吸附剂和掺杂金属元素（K、Na、Be、Ca、Al）的Li₄SiO₄吸附剂的CO₂吸附机理，并通过热重测试掺杂后吸附剂的吸附量和循环性能。最终得到，Li₄SiO₄（010）表面O原子中的p轨道占O占据轨道的主导地位，使表面的O原子更有可能成为化学吸附反应的电子给体。不同价态的金属掺杂降低了CO₂吸附在Li₄SiO₄（010）表面的能量，尤其碱金属K、Na使CO₂更容易吸附到Li₄SiO₄（010）表面，在其表面形成碳酸盐使得CO₂流向碳酸盐熔体层的速度比流向固体产物层的速度快，提高了Li₄SiO₄（010）表面的吸附性能。然而，并非所有的掺杂都具有高活性位点。Be的掺杂抑制了CO₂向CO₃^2-的转化，降低了Li₄SiO₄（010）表面对CO₂的稳定吸附。

K和Al共掺杂可以改善Li₄SiO₄（010）表面对CO₂的吸附性能。在K+Al-Li₄SiO₄体系中CO₂的吸附能（-2.38 eV）远远大于未改性Li₄SiO₄的吸附能（-1.17 eV），Li₄SiO₄（010）表面更多的电子向CO₂转移，使得Li₄SiO₄（010）表面具有更高活性，有利于CO₂向CO₃^2-的转化。实验中K和Al的共掺杂，其吸附总量低于K、Al单掺杂，吸附能与吸附量的关系有待商讨。K和Al共掺杂使Li₄SiO₄对CO₂的吸附温度降低40-60℃，使得吸附CO₂的温度区间变宽，提高了低温下Li₄SiO₄对CO₂的吸附性能，并且在低CO₂ (CO₂, N₂平衡为15%)浓度下表现出稳定的循环吸附性能。

    该论文第一作者罗光权是常州大学2021级硕士研究生，常州大学是第一作者和通讯作者单位！

英文摘要：

  Lithium silicate (Li₄SiO₄) has good stability, high theoretical carbon dioxide (CO₂) adsorption capacity, and low regeneration temperature. It has great potential in the field of CO₂ adsorption. However, it is difficult to achieve the theoretical value in practical applications and a narrow temperature window for adsorption. Therefore, further research in this area is urgently needed. In this study, experimental and simulation methods were used to investigate the effects of single doping and co-doping with K, Na, Be, Ca, and Al metals on the adsorption performance and adsorption temperature window of Li₄SiO₄. Single doping with K, Na, or Al makes CO₂ easier to be adsorbed on the Li₄SiO₄ (010) surface by increasing the charge transfer from the Li₄SiO₄ surface to CO₂. Co-doping with K and Al increases the adsorption energy of CO₂ on the Li₄SiO₄ (010) surface, enhances hybrid peaks, and broadens the temperature range for CO₂ adsorption on the Li₄SiO₄ surface. It exhibits stable cyclic adsorption performance under low CO₂ (15% CO₂, N₂ balance) concentration, and more electron transfer facilitates the formation of carbonate species on the Li₄SiO₄ (010) surface at lower temperatures, thereby improving its CO₂ adsorption performance.

图解摘要：

原文链接：https://doi.org/10.1016/j.ceramint.2023.12.246

撰稿：2021级硕士研究生罗光权    审核：朱宝忠