Influence of Metal–Organic Framework Porosity on Hydrogen Generation from Nanoconfined Ammonia Borane

Abstract

Hydrogen released from chemical hydride ammonia borane (AB, NH3BH3) can be greatly improved when AB is confined in metal–organic frameworks (MOFs), showing reduced decomposition temperature and suppressed unwanted byproducts. However, it is still debatable whether the mechanism of improved AB dehydrogenation is due to catalysis or nanosize. In this research, selected MOFs (IRMOF-1, IRMOF-10, UiO-66, UiO-67, and MIL-53­(Al)) were chosen to explore both catalytic effect of the metal clusters and the manipulation of pore size for nanoconfinement by variations in ligand length. When AB particle size was restricted by the controlled micropores of MOFs, we observed that the decomposition temperature was not correlated to the MOF catalytic environment, but inversely proportional to the reciprocal of the particle size. The results correspond well with the derived thermodynamic model for AB decomposition considering surface tension of nanoparticles.

Deciphering the Supramolecular Organization of Multiple Guests Inside a Microporous MOF to Understand their Release Profile

“…Only two partially occupied thymol molecules are observed:t hymol-E (50 %o ccupancy) is approaching the anet through the C = Oofthe amide group while an additional heavily disordered thymol molecule (thymol-f,o ccupancy 25 %) is bridged by DMF-II. Thed isordered distribution of the guest molecules did not allow to further allocate residual Angewandte electron density that results in unmodeled 367 e À (800 3 residual voids per unit cell).…”

Progress in modification and thermodynamic tuning of light hydrogen storage materials

“…Li-Mg-N-H体系, Pinkerton等 [83] 将LiBH 4 与LiNH 2 按照摩 尔比为1:2复合得到Li-B-N-H体系, 当温度升高至350℃ 时, 体系放氢量达10 wt%; 然而脱氢温度较实际应用仍 相对较高. 陈萍等 [84] (e) EDS 能谱图: (f) O; (g) Ce; (h) Al; (i) Na [72] (网络版彩图) [89] 、活性炭 [90] 、MCM-41 [91] 等材料纳米限域;…”

Advances and Prospects in Metal–Organic Frameworks as Key Nexus for Chemocatalytic Hydrogen Production

“…Notably, although LiBH 4 and NaAlH 4 also feature high gravimetric hydrogen capacity (≈18.3 wt% and 7.4 wt%, respectively), the literature instances concerning H 2 production from LiBH 4 or NaAlH 4 utilizing MOFs as catalysts or catalyst supports are very rare, and the limited examples have been reviewed by Rossin et al. [ 13 ] Therefore, this review concentrates on the application of MOFs as key nexus (heterogeneous catalysis or catalyst supports) for chemocatalytic hydrogen production, involving H 2 production from hydrolysis of the lightweight inorganic hydrides, pyrolysis of ammonia borane encapsulated in MOF (AB@MOF composites), [ 48 ] as well as methanol steam reforming process. Recent developments in this field are comprehensively summarized here from a catalytic viewpoint.…”