Kim, Yongmin Baek, Hyunjae Lee, Jin Hee Yeo, Shinyoung Kim, Kibum Hwang, Son-Jong Eun, Bit Nam, Suk Woo Lim, Tae-Hoon Yoon, Chang Won 2024-01-20T11:01:55Z 2024-01-20T11:01:55Z 2021-09-05 2013-12 1463-9076 https://pubs.kist.re.kr/handle/201004/127374 Polyetheral additives were found to be efficient promoters to enhance the rate of H-2-release from ammonia borane (AB) at various temperatures. In particular, tetraethylene glycol dimethyl ether (T4EGDE, 29 wt% relative to AB + T4EGDE) exhibited significantly improved activities for AB dehydrogenation, with the material-based hydrogen storage capacity of 10.3 wt% at 125 degrees C within 40 min. In situ FT-IR spectroscopy indicated the formation of B-(cyclodiborazanyl) amino-borohydride (BCDB), borazine, and mu-aminodiborane as gaseous byproducts. In addition, B-11 nuclear magnetic resonance (NMR) spectroscopy further revealed that diammoniate of diborane (DADB) was initially formed to give polyaminoborane as liquid and/or solid spent-fuel, consistent with previous reports. Density Functional Theory (DFT) calculations suggested that hydrogen bonding interactions between AB and a polyetheral promoter initially played an important role in increasing the reactivity of B-H bonds of AB by transferring electron density from oxygen atoms of the promoter into B-H bonds of AB. These partially activated, hydridic B-H bonds were proposed to help promote the formation of diammoniate of diborane (DADB), which is considered as a reactive intermediate, eventually enhancing the rate of H-2-release from AB. In addition, our in situ solid state B-11 magic angle spinning (MAS) NMR measurements further confirmed that the rate of DADB formation from AB with a small quantity of T4EGDE was found to be much faster than that of pristine AB even at 50 degrees C. This metal-free method for H-2-release from AB with an added, small quantity of polyethers would be helpful to develop feasible hydrogen storage systems for long-term fuel cell applications. English ROYAL SOC CHEMISTRY CATALYZED DEHYDROGENATION H-2 RELEASE THERMAL-DECOMPOSITION COMPLEXES STORAGE MECHANISM FUEL CRYSTAL IRIDIUM DIAMMONIATE Metal-free, polyether-mediated H-2-release from ammonia borane: roles of hydrogen bonding interactions in promoting dehydrogenation Article 10.1039/c3cp52591k 1 PHYSICAL CHEMISTRY CHEMICAL PHYSICS, v.15, no.45, pp.19584 - 19594 PHYSICAL CHEMISTRY CHEMICAL PHYSICS 15 45 19584 19594 scie scopus 000326470200011 2-s2.0-84887009304 Chemistry, Physical Physics, Atomic, Molecular & Chemical Chemistry Physics Article CATALYZED DEHYDROGENATION H-2 RELEASE THERMAL-DECOMPOSITION COMPLEXES STORAGE MECHANISM FUEL CRYSTAL IRIDIUM DIAMMONIATE