直接捕获空气中CO2的小分子吸附剂研究进展

Advances in small molecule adsorbents for direct air capture of carbon dioxide

摘要:

碳捕获和碳储存是降低大气中二氧化碳浓度和稳定全球气温的关键策略。基于大气二氧化碳浓度较低(约为0.415 ‰)、吸附过程需要较高的能量(21 kJ/mol)以及巨大的经济投入(到2050年,每年需要捕获至少10 Gt二氧化碳)等问题,开发具有高二氧化碳吸附选择性、结构稳定、成本低廉的吸附剂具有重要意义。小分子吸附剂因其优异的二氧化碳吸收速率、较低的解吸温度(低于120℃)以及较低的成本,在二氧化碳捕获中展现出良好的应用前景。本文综述了近年来小分子吸附剂从空气中直接吸收二氧化碳的研究进展,重点介绍了一些典型的超分子主体吸附剂的设计与应用,例如线形、多臂形、环形和笼形等不同形状的吸附剂分子结构。这类小分子吸附剂通常包括氢键供体单元如脲基、硫脲、胍基,通过其与HCO3/CO3离子形成氢键作用,实现二氧化碳的固定。

Abstract:

Carbon capture and storage (CCS) is a key strategy for reducing atmospheric CO2 concentrations and stabilising global temperatures. Based on the low atmospheric CO2 concentration (about 0.415 ‰), the high energy (21 kJ/mol) required for the adsorption process, and the huge economic investment (at least 10 Gt of CO2 will need to be captured annually by 2050), the development of adsorbents with high selectivity for CO2 adsorption, structural stability, and low cost is of great significance. Small molecule adsorbents show good application prospects in CO2 capture due to their excellent CO2 uptake rate, low desorption temperature (below 120°C) and low cost. In this paper, we review the research progress of small molecule adsorbents for direct CO2 uptake from air in recent years, focusing on the design and application of some typical supramolecular-body adsorbents, such as the molecular structures of adsorbents with different shapes, such as linear, dobby, ring, and cage shapes. These small molecule adsorbents usually include hydrogen bond donor units such as ureido, thiourea, and guanidino groups, which enable carbon dioxide fixation through their hydrogen bonding interactions with HCO3/CO3 ions.