摘要/Abstract

光响应CO₂吸附剂能够通过外部光照的方式有效调节其捕获CO₂的能力，在吸附过程中具有可控性好和能源利用效率高的优势.然而目前报道的光响应CO₂吸附剂主要用于对弱吸附位点的调控，对强吸附位点的调控仍然是一项具有挑战性的任务.本工作构筑了一种光响应智能吸附剂，实现了对CO₂强吸附位点的光响应调控.吸附剂的构筑通过将具有顺反异构体的偶氮苯衍生物和含有伯胺的硅烷偶联剂引入介孔氧化硅实现.光照前偶氮苯处于反式构型，导致伯胺的静电势降低，充分暴露活性位；光照后偶氮苯转变为顺式构型，导致伯胺静电势的增加以及活性位点的遮蔽.吸附量在两种状态下的变化率能够达到43%，并且这一调节过程是可逆的.偶氮苯在不同构型下对伯胺的静电势产生了差异化的影响，从而实现了对吸附能力的调控.
关键词: CO₂吸附, 光响应开关, 强吸附位点, 选择性吸附, 智能吸附剂
Light-responsive CO₂ adsorbents can effectively adjust their ability to capture CO₂ through external light irradiation, and have the advantages of good controllability and high energy efficiency during the adsorption process. However, the currently reported light-responsive CO₂ adsorbents can only realize the regulation of weak adsorption sites, and the regulation of strong adsorption sites is still a challenging task. In this work, a light-responsive smart adsorbent was constructed by in situ synthesis, and the light-responsive control of strong adsorption sites for CO₂ was realized. The construction of adsorbent was achieved by introducing the azobenzene derivative with cis and trans isomers and silane coupling agent containing primary amines into mesoporous silica. The characterization results show that the adsorbents have uniform pore channels, and primary amine and light-responsive groups are dispersed on the pore walls. The strong interaction between primary amine and CO₂ can lead to the selective adsorption of CO₂, while azobenzene as a molecular switch can regulate the adsorption performance of primary amine. Before light irradiation, azobenzene is in trans configuration, which decreases the electrostatic potential of the primary amine, and exposes the active site, thus CO₂ can be freely adsorbed; after light irradiation, azobenzene is converted to the cis configuration, which increases the electrostatic potential of the primary amine and shields the active sites. The change amount of adsorption capacity can reach 43%, and this process is reversible. Both the light-responsive properties of azobenzene groups and the adsorptive performances of adsorbents can be well maintained after 5 cycles. Azobenzene in different configuration has distinctive influences on the electrostatic potential of primary amine, thereby achieving the regulation of adsorption ability. This work utilizes the specific interaction between stimuli-responsive groups and target-specific adsorption sites, realizing the regulation of strong active cites for CO₂, which gives clues to the development of new smart adsorbents.
Key words: CO₂ adsorption, light-responsive switch, strong adsorption site, selective adsorption, smart adsorbent


PDF全文下载地址:

点我下载PDF