Reversible hydrogen desorption from LiBH4 catalyzed by graphene supported Pt nanoparticles

Abstract

The thermally induced de-/rehydrogenation performance of the graphene supported Pt nanoparticles (Pt/G) doped LiBH4 was greatly improved even at very low catalyst content due to a synergetic effect of Pt addition and nanoconfinement in graphene. For the 5 wt% Pt/G doped LiBH4 sample, the onset hydrogen desorption temperature is about 140 °C lower than that of the pure LiBH4. With increasing loading of the Pt/G catalysts in LiBH4 samples, the onset dehydrogenation temperature and the two main desorption peaks from LiBH4 were found to decrease while the hydrogen release amount increased. About 17.8 wt% can be released from the 50 wt% Pt/G doped LiBH4 sample below 500 °C. Moreover, variation of the equilibrium pressure (350-450 °C) indicates that the dehydrogenation enthalpy is reduced from 74 kJ mol(-1) H2 for the pure LiBH4 to ca. 48 kJ mol(-1) H2 for the 10 wt% Pt/G doped LiBH4, showing improved thermodynamic properties. More importantly, a reversible capacity of ca. 8.1 wt% in the 30th de-/rehydrogenation cycle was achieved under 3 MPa H2 at 400 °C for 10 h, indicating that the Pt/G catalysts play a crucial role in the improvement of the hydrogen uptake reversibility of LiBH4 at lower temperature and pressure conditions. Especially, LiBH4 was reformed and a new product, Li2B10H10, was detected after the rehydrogenation process.

Combined X-ray and Raman Studies on the Effect of Cobalt Additives on the Decomposition of Magnesium Borohydride

“…The addition of several TM-compounds has indeed resulted in improved hydrogen storage properties of stable borohydrides and related composites, including decrease in Tdec [35,41], in some cases remarkably by as much as 200 °C [36]. Enhancement of the desorption and absorption reactions kinetics [26,42], improved hydrogen purity, reversibility [37] and borohydride synthesis from the decomposition products [39] has also been documented.…”

Fe3O4 nanoclusters highly dispersed on a porous graphene support as an additive for improving the hydrogen storage properties of LiBH4

“…25 The addition of functional graphene to LiBH 4 could result in a high hydrogen storage capacity, rapid kinetics, and excellent reversibility. Xu et al 26,27 reported that precious metal (Pt and Pd) nanoparticles anchored onto graphene sheets could greatly improve the hydrogen desorption behavior and uptake reversibility of LiBH 4 . The artful combination of catalysis and nanoconnement has become a promising way to improve the dehydrogenation and rehydrogenation performance of LiBH 4 .…”

Composite cooperative enhancement on the hydrogen desorption kinetics of LiBH4 by co-doping with NbCl5 and hexagonal BN

“…MS results demonstrate that the gas released from all samples is pure H 2 without B 2 H 6 or NH 3 impurity. Furthermore, the onset dehydrogenation temperature of NbCl 5 /h-BN co-doped LiBH 4 is reduced to 180 C, which is 100 C lower than that of the ball milled LiBH 4 [31,32]. Also, the major desorption peak temperatures of LiBH 4 -0.01NbCl 5 -0.3BN sample is 377 C, which is much lower than the other three samples.…”