Tuning the Gate Opening Pressure of Metal Organic Frameworks (MOFs) for the Selective Separation of Hydro-carbons

TL;DR

This paper demonstrates how tuning the gate opening pressure of flexible MOFs can enable selective hydrocarbon separation, revealing new mechanisms based on chain length and framework-gas interactions.

Contribution

It introduces a method to control MOF gate opening pressures for improved hydrocarbon separation, combining experimental spectroscopy and theoretical calculations.

Findings

Hydrocarbon selectivity depends on chain length and framework interactions.

Gate opening behavior can be tuned for selective adsorption.

Mechanisms involve differences in framework-gas interactions.

Abstract

Separation of hydrocarbons is one of the most energy demanding processes. The need to develop materials for the selective adsorption of hydrocarbons, under reasonable conditions, is therefore of paramount importance. This work unveils unexpected hydrocarbon selectivity in a flexible Metal Organic Framework (MOF), based on differences in their gate opening pressure. We show selectivity dependence on both chain length and specific framework-gas interaction. Combining Raman spectroscopy and theoretical van der Waals Density Functional (vdW-DF) calculations, the separation mechanisms governing this unexpected gate opening behavior are revealed.