Carbon aerogel-encapsulated RuPd nanoalloys: Facile preparation and application in effectively boosting NH3BH3 hydrolytic dehydrogenation

Ammonia borane (AB, NH3BH3) with extremely high hydrogen content (19.6 wt%) is considered to be one of the most promising chemical hydrides for storing hydrogen. According to the starting materials of AB and H2O, a hydrogen capacity of 7.8 wt% is achieved for the AB hydrolytic dehydrogenation system with the presence of a highly efficient catalyst. In this work, ruthenium nanoparticles supported on magnesium–aluminum layered double hydroxides (Ru/MgAl-LDHs) were successfully synthesized via a simple method, i.e., chemical reduction. The effect of Mg/Al molar ratios in MgAl-LDHs on the catalytic performance for AB hydrolytic dehydrogenation was systematically investigated. Catalyzed by the as-synthesized Ru/Mg1Al1-LDHs catalyst, it took about 130 s at room temperature to complete the hydrolysis reaction of AB, which achieved a rate of hydrogen production of about 740 ml s−1 g−1. Furthermore, a relatively high activity (TOF = 137.1 molH2 molRu−1 min−1), low activation energy (Ea = 30.8 kJ mol−1) and fairly good recyclability of the Ru/Mg1Al1-LDHs catalyst in ten cycles were achieved toward AB hydrolysis for hydrogen generation. More importantly, the mechanism of AB hydrolysis catalyzed by Ru/MgAl-LDHs was simulated via density functional theory. The facile preparation and high catalytic performance of Ru/MgAl-LDHs make it an efficient catalyst for hydrolytic dehydrogenation of AB.

Stratified nanoporous PtTi alloys for hydrolysis of ammonia borane

CoMo nanoparticles (NPs) supported on reduced graphene oxide (RGO) were synthesized by a one-step in situ co-reduction of an aqueous solution of cobalt(II) chloride, sodium molybdate dihydrate and graphene oxide (GO) using NaBH4 as the sole reductant under ambient conditions. The powder XRD, FTIR, EDS and TEM were employed to characterize the structure, size and composition of the CoMo/RGO catalysts. The as-synthesized Co0.9Mo0.1/RGO catalysts exhibited high catalytic activity for the hydrolytic dehydrogenation of ammonia borane (AB) at room temperature. The as-synthesized Co0.9Mo0.1/RGO nanocatalysts exhibited much higher catalytic activity than Co/RGO, Mo/RGO and the RGO-free Co0.9Mo0.1 counterpart. Moreover, kinetic studies indicate that the catalytic hydrolysis of AB by Co0.9Mo0.1/RGO has first order kinetics with respect to the the catalyst concentration, but zero order kinetics with respect to the substrate concentration. The Co0.9Mo0.1/RGO catalyst has a turnover frequency (TOF) of 15.8 mol H2·(mol·Co0.9Mo0.1/RGO)−1·min−1 at 25°C. Furthermore, the Co0.9Mo0.1/RGO show good recyclability for hydrogen generation from an aqueous solution of AB, which enables the practical reuse of the catalysts. Hence, this general method can be easily extended to the facile preparation of other RGO-based metallic systems.

Preparation and characterization of fishbone-like Co–B nanoparticles with high catalytic activity for hydrogen generation from NaBH4 solution

Remarkably boosting Ru-Ni nanocatalysis via surface/interface regulation for efficient hydrolytic dehydrogenation of ammonia borane

Hierarchical nanoporous platinum–copper alloy nanoflowers as highly active catalysts for the hydrolytic dehydrogenation of ammonia borane

In this study, well dispersed Cu@Co core–shell nanoparticles (NPs) on rGO surfaces were successfully synthesized via a one-step in situ procedure using methylamine borane (MeAB) as reductant under ambient conditions. The Cu@Co/rGO NPs exhibit superior catalytic activity than their alloy (CuCo/rGO) and graphene-free (Cu@Co) counterparts toward the hydrolytic dehydrogenation of ammonia borane (AB). Additionally, compared with the NPs reduced by AB, the as-synthesized Cu@Co/rGO NPs generated by the weaker reducing agent MeAB exhibit higher catalytic activities. Furthermore, the as-synthesized NPs exerted satisfactory catalytic activities and recycle stabilities for the hydrolysis of MeAB. Moreover, this general method indicates that MeAB can be used as both a potential hydrogen storage material and an efficient reductant which can be easily extended to the facile preparation of other rGO-supported metal NPs.

Strategic synthesis of graphene supported trimetallic Ag-based core–shell nanoparticles toward hydrolytic dehydrogenation of amine boranes

The synthesis of ultrafine well-dispersed bimetallic RuM (M: Co, Ni, Cu) nanoparticles (NPs) supported on graphene hydrogel (GH) was accomplished by a novel one-pot wet-chemical protocol that comprised the hydrothermal reduction of the mixture of graphene oxide and metal precursors by ethylene glycol (EG) in a Teflon-coated stainless-steel reactor at 180 °C. In this study, for the first time, we report the synthesis of bimetallic RuM NPs anchored on GH during the hydrothermal production of GH from graphene oxide (GH-RuM) and the catalysis of the yielded GH-Ru in the hydrolysis of ammonia borane (AB). As-synthesized GH-RuM (M: Co, Ni, Cu) nanocatalysts were characterized by using many advanced instrumental techniques including TEM, XRD, XPS, and ICP-MS. The bimetallic catalysts denoted as GH-Ru20Co80, GH-Ru30Ni70 and GH-Ru10Cu90 exhibited much higher catalytic activity compared to their Ru, Co, Ni and Cu monometallic counterparts in the hydrolytic dehydrogenation of AB. The catalytic performance of as-prepared NPs in terms of hydrogen generation rate (HGR) was achieved in the order of RuCo > RuNi > RuCu and the highest HGR calculated for the catalyst GH-Ru20Co80 reached 8911.5 mL H2 gcat −1 min−1 at room temperature with an activation energy of 52.5 kJ mol−1.