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

Shan Jiang, Jingyan Liu, Jiwen Guan, Xin Du, Shoushun Chen, Yang Song*, Yining Huang*

Scientific Reports 2023, 13, 17584.

DOI:10.1038/s41598-023-44960-4

Abstract

Metal–organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs) are promising porous materials for adsorption and storage of greenhouse gases, especially CO₂. In this study, guided by the CO₂ phase diagram, we explore the adsorption behavior of solid CO₂ loaded with ZIF‑8 framework by heating the sample under high pressures, resulting in a drastic improvement in the CO₂ uptake. The behavior of CO₂ under simultaneous high temperature (T) and pressure (P) conditions is directly monitored by in situ FTIR spectroscopy. The remarkable enhancement in CO₂ adsorption capability observed can be attributed to the synergetic effect of high T and P: high temperature greatly enhances the transport property of solid CO₂ 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 CO₂ adsorptive capability in MOFs/ZIFs using pressure and temperature combined as a synergetic approach.