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

Efficient capture and selective separation of CO2 is of great significance for alleviating the greenhouse effect. However, it is still a challenge to achieve efficient, reversible and selective capture of CO2. Here, stable Al-based MOFs with multiple adsorption sites were constructed for capture and selective separation CO2. It was found that MOF-303(Al) with multiple active sites (μ-OH, N-H, N-N and H-C) demonstrated a high CO2 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 CO2 from CO2/CH4 and CO2/N2 mixtures, which could be used as a potential material for natural gas purification. Mechanism results revealed that the excellent CO2 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.