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

Abstract

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.