Kevin Meaux

 Alternatives to fossil fuels to power transportation are sought  To use hydrogen for fuel, a more effective way of storing H 2 is needed  High volumetric density, hydrogen mass %, stability, and reversibility are desired  Liquid and gaseous H 2 are not dense enough  Metal hydrides and similar compounds offer potential solutions

For Comparison… descriptionNonhazardous stable white powder 1 Melting point 104 ⁰C (377 K) Density0.78 g/cm 3 Mass % H19.6% 1 Hydrogen Density0.153 g H/cm 3 H 3 N:BH 3 [1] Marder, T., Angewandte Chemie International Edition, 2007, 46, 8116–8118. Mass % H of LiAlH % Mass % H of NaBH % Density of L H g/cm 3

 For effective use, more info is needed on the dehydrogenation process of ammonia borane (AB)  Important first steps involve developing a working experimental setup to study this change

Infrared Spectroscopy Schematic  Using Transmittance Fourier Transform Infrared Spectroscopy  Characterizes a substance by the vibration of its chemical bonds

 KBr and NH 3 BH 3 are mixed in a 25:1 ratio  KBr alone and the KBr/AB mixture are pressed into a tungsten mesh in different spots  Have varied the reference salt, absolute amounts, and ratios Original Experimental Setup

Image produced by Oleg Byl sample reference tungsten mesh grid copper leads for resistive heating  Sample is under rough vacuum for analysis (~9E-2 torr)  Heated and then allowed to cool under argon (~5 torr)  New spectra is taken at room temperature and rough vacuum

10%

Our findings *Literature 2 Assignment 3386NH anti sym stretch NH sym stretch ??? ??? 2427B 10 H stretch B 11 H stretch BH stretch 2116 ??? 1656??? NH deformation 1591??? 1558 ??? NH deform 1301NH rock 1252 ??? BH deform 1060 B 10 H deform 1052B 11 H deform 987B 10 N stretch 968B 11 N stretch 783 ??? 725 ??? 603BH rock *This table compares reference IR peaks for ammonia borane with data gathered for 300K [2] JJ. Smith, K. S. Seshadri, and David White: J. Mol. Spec., 1973, 45,

 The 1126,2225, and 2291 peaks shown forming at 433 K correspond to KBH 4 3  The 1959/2029 peaks formed at 913 K are likely the formation of B 11 O 2 /B 10 O 2 anions 4  The other peaks observed at 433 K do not fit with borazine, boron oxides, or boron nitride [4] I.C. Hisatsune and Noelia Haddock Suarez: Inorganic Chemistry, 1964, 3, [3] K. B. Harvey and N. R. McQuaker: Canadian Journal of Chemistry, 1971, 49,

 Had problems with KBr reactivity in pellet preparation  Instead it is prepared on a KBr window  Dissolved AB in THF  Deposited solution on KBr disk  Boiled off THF (67 C)  Mounted disk onto mesh Thermocouple KBr Window

2.9 mg NH 3 -BH 3 dissolved in 0.7 mL THF and deposited on KBr disk. KBr disk is mounted on tungsten mesh, on which thermocouple was spot-welded. Sample was heated under 0.1 torr pressure and spectra collected at room temperature.

* Evaporated THF solution on KBr window Pressed KBr PelletLiterature 2 Assignment 3386NH anti sym stretch NH sym stretch ??? ??? 2427B 10 H stretch B 11 H stretch BH stretch 2116 ??? ??? NH deformation 1591??? ??? NH deform 1301NH rock ??? BH deform B 10 H deform 1052B 11 H deform 987B 10 N stretch 968B 11 N stretch 783 ??? 725 ??? BH rock

 The new sample prep method shows more clearly resolved peaks  The accuracy of temperatures needs to be verified  The peaks are shifted somewhat from literature values  The spectra demonstrates dehydrogenation with heating  Neither the KBH 4 nor BO 2 - peaks are seen

 AB can be useful as a hydrogen storage media  More work needs to be done in characterizing its dehydrogenation  Current method yields noisy spectra but shows potential  Will be dealing with the noise issues in the near future

This work was supported by the National Science Foundation under EEC-NSF Grant # I would like to thank Dr. Trenary and Dr. Jash for their guidance, as well as Dr. Takoudis and Dr. Jursich for administrating the UIC REU program