Tuning the Gate Opening Pressure of Metal–Organic Frameworks (MOFs) for the Selective Separation of Hydrocarbons

Nijem, N.; Wu, H.; Canepa, P.; Marti, A.; Balkus, K. J.; Thonhauser, T.; Li, J.; Chabal, Y. J.

doi:10.1021/ja305754f

Tuning the Gate Opening Pressure of Metal–Organic Frameworks (MOFs) for the Selective Separation of Hydrocarbons

N. Nijem, H. Wu, P. Canepa, A. Marti, K. J. Balkus, T. Thonhauser, J. Li, and Y. J. Chabal; J. Am. Chem. Soc. 134, 15201–15204 (2012).

BibTeX

@article{Nijem2012tuning,
  author  = {Nijem, N. and Wu, H. and Canepa, P. and Marti, A. and Balkus, K. J. and Thonhauser, T. and Li, J. and Chabal, Y. J.},
  title   = {{Tuning the Gate Opening Pressure of Metal–Organic Frameworks (MOFs) for the Selective Separation of Hydrocarbons}},
  journal = {Journal of the American Chemical Society},
  volume  = {134},
  pages   = {15201--15204},
  year    = {2012},
  doi     = {10.1021/ja305754f}
}

Brief summary

Separating hydrocarbons is one of industry's most energy-hungry processes. We found that a flexible metal–organic framework opens its pores at a different gas pressure for each hydrocarbon, depending on its chain length and how it interacts with the framework, and explain this selective “gate opening” with Raman spectroscopy and calculations.

Full 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. By combining Raman spectroscopy and theoretical van der Waals Density Functional (vdW-DF) calculations, the separation mechanisms governing this unexpected gate-opening behavior are revealed.