Ammonia borane confined by poly(methyl methacrylate)/multiwall carbon nanotube nanofiber composite, as a polymeric hydrogen storage material

Abstract

In this work, poly(methyl methacrylate)/ammonia borane/multiwall carbon nanotube (PMMA/AB/ MWCNT) nanofiber composites have been fabricated and the synergetic nanoconfinement effect of nanofiber and CNT components on dehydrogenation temperature and liberating unwanted byproducts of AB (NH 3 BH 3 ) have been studied. The results of dehydrogenation of PMMA/AB and PMMA/ AB/MWCNT samples show 112 and 85°C exothermic reaction temperatures, which are dramatically lower than pure AB (120°C). Furthermore, by capture and interaction of AB molecules in the MWCNT and PMMA nanofiber structures, the enthalpy of exothermic decomposition decreases from -21.00 to -1.83 kJ mol -1 H 2 , suggesting that this type of AB nanofiber composite can provide a convenient reversible hydrogen storage material. The utilization of MWCNT as carbon catalyst and confining of AB result in a decrease of ammonia borane weight loss from 60.00 to 2.88 wt% which in turn can vigorously decline the emission of byproduct impurities. The synthesis process of PMMA/AB/MWCNT nanofiber composites causes the crystal structure of AB particles changed to the amorphous structure which has been clearly confirmed by X-ray diffraction analyses. The strategy of combining nanofiber structure and MWCNT as carbon catalyst with AB particles can be presented as a practicable solution to reach lower operational temperature and to decline undesirable volatile products.

Crystalline structure of an ammonia borane–polyethylene oxide cocrystal: a material investigated for its hydrogen storage potential

“…Polymer composites are a particularly attractive option to implement these approaches, since polymers can be cheap and lightweight. To date, polyIJmethyl acrylate), 22 polyIJmethyl methacrylate), 23 polyIJvinyl pyrrolidone) 24 and polyacrylamide 25 composites have been successfully produced with AB. These materials combine confinement effects and chemical interactions between AB and oxygen-containing functional groups within the polymer to improve the properties of the hydrogen storage material.…”

Improved hydrogen release from ammonia borane confined in microporous carbon with narrow pore size distribution

“…4,5 However, despite these merits, there are technical barriers preventing AB to be practically used as an on-board energy source, such as its slow thermal kinetics below 100 C and unwanted by-products including ammonia (NH 3 ), diborane (B 2 H 6 ), and borazine (B 3 H 6 N 3 ), which will poison the catalyst in a proton membrane fuel cell. 2,3,[6][7][8] To date, a number of ways have been investigated to tackle the above mentioned issues including the use of metal catalysts 3,[9][10][11][12][13][14][15][16][17] or metal-free catalysts, [18][19][20] the formation of metal hydrides, [21][22][23] the realisation of metal or methane substitution, [24][25][26] the utilisation of ionic liquid, 27,28 additives, 29,30 or nanoconfinement 8,[31][32][33][34][35][36][37][38][39][40] etc. Significant improvements on lowering the hydrogen release temperatures, improving the kinetics and avoiding the emissions of those harmful by-products have been made.…”

“…[42][43][44] The first report on nanoconfinement of AB in mesoporous silica demonstrated a lower dehydrogenation temperature, suppression of borazine release, and lower enthalpy of the decomposition, 31 which has triggered a number of studies in this area. Nanoscaffolds including mesoporous silica, 31,[45][46][47] mesoporous carbon, 32,38,48,49 activated carbon, 50 carbon nanotubes, 39,40 metal-organic frameworks (MOFs), 8, 33, 36, 37, 51-53 porous MnO 2 35 and low-density porous aromatic framework 34 have been studied.…”

Combined Effect of Functionality and Pore Size on Dehydrogenation of Ammonia Borane via Its Nanoconfinement in Polyacrylamide-Grafted Organically Modified Mesoporous Silica

“…Similar observations have been previously reported by Li et al 26 where blending of PAM was performed with AB, and a reduced dehydrogenation temperature was observed due to the interaction between CO, NH 2 of the polymer, and the AB molecule. Alipour et al 51 reported fabrication of poly(methyl methacrylate)/ammonia borane/multiwall carbon nanotube (PMMA/AB/MWCNT) nanofiber composites for studying the dehydrogenation behavior of AB in these composites. It was observed that the interaction between the oxygen group from the carbonyl group of PMMA and the boron from AB led to formation of B−O bonds.…”