Effect of Functional Groups on Low-Concentration Carbon Dioxide Capture in UiO-66 -Type Metal-Organic Frameworks.

The selective capture of low-concentration CO 2 from air or confined spaces remains a great challenge. In this study, various functional groups were introduced into UiO-66 to generate functionalized derivatives ( UiO-66-R , R = NO 2 , NH 2 , OH , and CH 3 ), aiming at significantly enhancing CO 2 adsorption and separation efficiency. More significantly, UiO-66-NO 2 and UiO-66-NH 2 with high polarity exhibit exceptional CO 2 affinity and optimal separation characteristics in mixed CO 2 /O 2 /N 2 (1:21:78). In addition, the impressive stability of UiO-66-NO 2 and UiO-66-NH 2 endows them with excellent recycling stability. The effective adsorption and separation performances demonstrated by these two functional materials suggest their potential as promising physical adsorbents for capturing low-concentration CO 2 .