Growth of Crystalline Polyaminoborane through Catalytic Dehydrogenation of Ammonia Borane on FeB Nanoalloy

Abstract

CAS [KGCX2-YW-806, KJCX2-YW-H21, 2009AA05Z108, 2010CB631304]; US Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-06CH11357

Quasi in situ Mössbauer and XAS studies on FeB nanoalloy for heterogeneous catalytic dehydrogenation of ammonia borane

“…10) pattern of the postdehydrogenated Fe-doped AB is different from that of the Fe foil. Since ferric or ferrous salts are easy to be reduced by BH 4 − and alloy with B to form amorphous Fe-B alloys in solution [40,42], FeCl 2 in the sample may be reduced and alloy with B in AB during sample preparation and dehydrogenation treatment, which is confirmed by previous report [1] and Mössbauer characterization as mentioned above. The post-dehydrogenated sample shows a much broadened peak with the absence of high-order coordination peaks indicating an amorphous state of Fe species consistent with XRD results.…”

“…Thus, for FeCl 2 -doped AB sample, 5.0 mol.% loading gave the best performance in the formation of crystalline PAB. In our previously report, FeB nanoalloys were identified as functional species in the post-dehydrogenated Fe-Based catalyst loading AB sample [1]. However, changes of Fe chemical state during the dehydrogenation process were not studied in details.…”

“…In this context, the direct catalytic modification of solid phase AB is viewed as an attractive mean. Recently, we reported nanosized Co-, Ni- [27] and Fe-Based [1] catalysts on the heterogeneous catalytic dehydrogenation of AB and achieved approximately 1 equiv. H 2 desorption from the catalyst-doped samples at a temperature as low as 60 • C with significantly depression of sample foaming and byproducts (borazine and NH 3 ).…”

“…H 2 can be evolved from a Fe-modified ammonia borane (AB) sample at a temperature as low as 60• C with significant depression of induction period, sample foaming and toxic byproducts [1]. In this study, the effects of catalyst precursors and catalyst loading were investigated on the hydrogen desorption profile and the formation of crystalline polyaminoborane (PAB).…”

Metathesis of alkali-metal amidoborane and FeCl3 in THF

“…Similar phenomena were observed in our previous investigations on doping AB with Co and Fe catalysts. 25,26 Both Co 2+ and Fe 3+ in their chloride precursors were on-site reduced by AB to form Co-B and Fe-B alloys. Though synthesis of Fe amidoborane is unsuccessful in this work, it was still worthwhile to investigate the metathesis and reduction process and unveil the chemical nature of the resulting solids because Fe-B or Fe-N or even Fe-B-N based materials are likely produced at end of the reaction, which may function as catalysts.…”