Enhancing CO2 adsorption capacity of ZIF-8 by synergetic effect of high pressure and temperature

Abstract

Abstract Metal–organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs) are promising porous materials for adsorption and storage of greenhouse gases, especially CO 2 . In this study, guided by the CO 2 phase diagram, we explore the adsorption behavior of solid CO 2 loaded with ZIF-8 framework by heating the sample under high pressures, resulting in a drastic improvement in the CO 2 uptake. The behavior of CO 2 under simultaneous high temperature (T) and pressure (P) conditions is directly monitored by in situ FTIR spectroscopy. The remarkable enhancement in CO 2 adsorption capability observed can be attributed to the synergetic effect of high T and P: high temperature greatly enhances the transport property of solid CO 2 by facilitating its diffusion into the framework; high pressure effectively modifies the pore size and shape via changing the linker orientation and creating new adsorption sites within ZIF-8. Our study thus provides important new insights into the tunability and enhancement of CO 2 adsorptive capability in MOFs/ZIFs using pressure and temperature combined as a synergetic approach.