Constructing multiple sites of metal-organic frameworks for efficient adsorption and selective separation of CO2.

[Display omitted] • Al-based MOFs with different number of active sites were developed for efficient adsorption and selective separation of CO 2. • MOF-303(Al) with multiple adsorption sites exhabited a high CO 2 capacity and selectivity of CO 2 to N 2 and CH 4. • MOF-303(Al) can be recycled more than 50 times by a energy-saving desorption process. • Multiple sites interactions of CO 2 with MOF-303(Al) is the key driven force for the adsorption and selective separation. Efficient capture and selective separation of CO 2 is of great significance for alleviating the greenhouse effect. However, it is still a challenge to achieve efficient, reversible and selective capture of CO 2. Here, stable Al-based MOFs with multiple adsorption sites were constructed for capture and selective separation CO 2. It was found that MOF-303(Al) with multiple active sites (μ-OH, N-H, N-N and H-C) demonstrated a high CO 2 capacity of 5.1 mmol/g, and can be recycled for more than 50 times. Moreover, MOF-303(Al) shows excellent selective separation performance of CO 2 from CO 2 /CH 4 and CO 2 /N 2 mixtures, which could be used as a potential material for natural gas purification. Mechanism results revealed that the excellent CO 2 adsorption and selective separation performance is arose from the multiple adsorption sites (μ-OH, N-H, N-N and C-H) of MOF-303(Al), where the contribution of μ-OH and N-H adsorption sites are higher than that of N-N and H-C sites. [ABSTRACT FROM AUTHOR]