Abstract Silica-supported amine adsorbents are extensively studied for CO2 capture. However, rational design of silica materials with specific pore structures as amine supports for large CO2 adsorption capacity, fast adsorption-desorption kinetics, easy regeneration, and good cyclic performance, still remains a challenge. Herein, we synthesize a series of ordered silicas with either bimodal or trimodal meso-macro porosities through a single- or double-templating route as supports for polyethylenimines (PEI) to make solid amine CO2 adsorbents. Bimodal silicas with textural mesopores and interconnected macropores are ideal supports at medium amine loading, illustrated by significantly high amine efficiencies, e.g., 50BPEI(800)/PS-80-00 achieves a CO2 uptake of 350 mg g-1 PEI at 75 oC, 1 bar, which is the one of the highest values among PEI/silica composites reported so far; however, further increase of amine loading leads to severe amine efficiency fading. In comparison, trimodal silicas with internal mesopores, textural mesopores, and interconnected macropores show outstanding performance at high amine loading, e.g., 70BPEI(800)/PS-80-187 exhibits a CO2 adsorption capacity of 215 mg g-1 adsorbent at 75 oC, 1 bar, which is one of the highest values among reported PEI/silica composites. Moreover, we also study the correlations of the CO2 adsorption capacity and kinetics, regeneration of adsorbent, and cyclic CO2 adsorption-desorption performance with the PEI type, PEI loading amount, and operation temperatures. This work brings insight into factors affecting the CO2 capture performance for amine-impregnated silica composites, providing an important guidance to design high-performance solid amine CO2 adsorbents in the near future.

中文翻译：

---

介孔大孔二氧化硅作为高性能固体胺CO2吸附剂载体的合理设计

摘要 二氧化硅负载的胺吸附剂被广泛研究用于 CO2 捕获。然而，合理设计具有特定孔结构的二氧化硅材料作为胺载体以实现大的 CO2 吸附容量、快速的吸附-解吸动力学、易于再生和良好的循环性能仍然是一个挑战。在此，我们通过单模板或双模板路线合成了一系列具有双峰或三峰大孔的有序二氧化硅作为聚乙烯亚胺 (PEI) 的载体，以制备固体胺 CO2 吸附剂。具有结构中孔和互连大孔的双峰二氧化硅是中等胺负载下的理想载体，具有显着高的胺效率，例如，50BPEI(800)/PS-80-00 在 75 oC 下实现了 350 mg g-1 PEI 的 CO2 吸收， 1 酒吧，这是迄今为止报道的 PEI/二氧化硅复合材料中的最高值之​​一；然而，胺负载量的进一步增加会导致胺效率严重下降。相比之下，具有内部介孔、结构介孔和互连大孔的三峰二氧化硅在高胺负载量下表现出出色的性能，例如，70BPEI(800)/PS-80-187 在 75 oC 下的 CO2 吸附容量为 215 mg g-1 吸附剂, 1 bar，这是已报道的 PEI/二氧化硅复合材料中的最高值之​​一。此外，我们还研究了 CO2 吸附容量和动力学、吸附剂再生和循环 CO2 吸附-解吸性能与 PEI 类型、PEI 负载量和操作温度的相关性。这项工作深入了解了影响胺浸渍二氧化硅复合材料 CO2 捕获性能的因素，