Mayer, Daniel A.. A fourier transform - infrared spectroscopy study of hydrogen interaction with metal-organic-frameworks. Retrieved from https://doi.org/doi:10.7282/T3MG7PW3
DescriptionIn the following the interaction of hydrogen with Metal-Organic-Frameworks investigated by Fourier-Transform Infrared (FT-IR) Spectroscopy is presented.
The study was performed using two different compounds: (Zn(BDC)(TED)0.5) ·2DMF·0.2 ·H2O and the very similar Ni(NDC)(TED), whose exact structure was not characterized yet.
The removal of the solvent N,N-dimethylformide (DMF) was shown during the initial activation procedure. In addition, the decrease of an adsorbed water mode between 2000 and 4000 cm [superscript -1] could be confirmed while the benzene ring structure of the organic linkers (1610-1550 cm [superscript -1] and 1420-1335 cm [superscript -1]) stayed intact. Furthermore the MOFs were exposed to high-pressure hydrogen (300-1000 psi) while performing in-situ FT-IR measurements. For the Zn-MOF new modes in the range from 4000 to 4300 cm [superscript -1] were observed and are believed to represent modes related to adsorption sites of hydrogen inside the MOF. After decreasing the pressure, these modes disappear slowly. No such results could be found for the Ni-MOF.
While the MOFs were exposed to high-pressure hydrogen a very intensive feature around 3400 cm [superscript -1] was observed. This mode was growing over time without any saturation and was identified as water inside the MOF whose origin was determined to be the hydrogen gas.
An additional feature extending from 2900 to 3200 cm [superscript -1] was associated with the destruction of C-H bonds. This development might be attributed to destructive effects of the water adsorption on the MOF or due to contaminations.
When considering MOF materials for storage application it hast be noted that the adsorption properties for water can interfere with other properties of the material.