Ni–Mo₂C Nanocomposites as Highly Efficient Catalysts for Hydrogen Generation from Hydrolysis of Ammonia Borane

Abstract

Supported non-noble metal nanomaterials have attracted much interest due to their promising application prospects in heterogeneous catalysis. γ-Al2O3-supported Ni–Mo x C catalysts have been synthesized using an impregnation method, followed by the carburization at 993 K under a 5% H2/Ar flow. The synthesized NiMo x C/γ-Al2O3 catalysts are characterized and first tested in the hydrolysis of ammonia borane (NH3BH3, AB) at 298 K. The X-ray photoelectron spectra analysis shows that the incorporation of Mo x C can enhance the dispersion of surface Ni and consequently improve the catalytic performance of NiMo x C/γ-Al2O3 in AB hydrolysis. The highest turnover frequency value of 75.1 min–1 toward the AB hydrolysis is obtained for 10Ni30Mo x C/γ-Al2O3 under the investigated reaction conditions. The kinetic studies of H2 evolution at a temperature range of 293–323 K determined an activation energy (E a) value of 33.12 kJ mol–1 over 10Ni30Mo x C/γ-Al2O3. Experimental results indicate that the synergistic effect of Ni and Mo2C is contributed to the high catalytic activity of 10Ni30Mo x C/γ-Al2O3. The obtained results in this work suggest that the hexagonal Mo2C can be a promising material in catalytic hydrogen generation from AB hydrolysis.

Functional Group Regulated Ni/Ti3C2Tx (Tx = F, −OH) Holding Bimolecular Activation Tunnel for Enhanced Ammonia Borane Hydrolysis

“…SI Table S2 also listed some Ni-based catalyst for AB hydrolysis reported in the literatures. Among them, Ni/Ti 3 C 2 T x -4 exhibited the best catalytic activity. − …”

Controllable Synthesis of MoC and Mo2C to Boost Hydrogen Generation from Ammonia Borane Hydrolysis

“…The catalytic activity was determined by measuring the H 2 generation rate from AB hydrolysis. All of the experiments were conducted using a thermostatic magnetic stirring apparatus, and H 2 generated was collected by a typical water displacement method, as reported in the literature . Typically, a suspension solution containing 10 mg of catalyst and 2.5 mL of deionized water was placed in a round-bottom flask (50 mL), followed by sonication for 2 min, and then was preheated at 298 K in a thermostatic water bath under continuous stirring.…”

“…Moreover, in our previous study, the ability of Mo 2 C to activate the water is also confirmed by the experimental studies on the NiMo x C/γ-Al 2 O 3 system. 32 However, a comparative study of α-MoC and Mo 2 C is not carried out so far. Therefore, an experimental or theoretical study would be made to explore the crystalline phase effect of Mo x C on the catalytic behavior of AB hydrolysis and subsequently establish the structure−activity relationship.…”

“…All of the experiments were conducted using a thermostatic magnetic stirring apparatus, and H 2 generated was collected by a typical water displacement method, as reported in the literature. 32 Typically, a suspension solution containing 10 mg of catalyst and 2.5 mL of deionized water was placed in a round-bottom flask (50 mL), followed by sonication for 2 min, and then was preheated at 298 K in a thermostatic water bath under continuous stirring. Meanwhile, an aqueous solution containing NaOH (0.2 g), AB (42 mg), and 2.5 mL of deionized water was quickly introduced into the above flask.…”

Ammonia borane as an efficient direct fuel in alkaline fuel cells: mechanism, catalysts, applications, and challenges

“…AB was applied in fuel cells in two ways: one is as a hydrogen storage material to produce H 2 [16][17][18][19][20] and another is as an anode fuel directly. 21,22 As the indirect application of AB, the dehydrogenation of AB has been widely studied in recent years owing to its high gravimetric hydrogen density (19.6 wt% H), and there are three methods to promote the dehydrogenation of AB, including thermolysis, [23][24][25][26] hydrolysis, 16,[27][28][29] and alcoholysis. 17,[30][31][32] The rational design of catalysts is the key to accelerating the production of H 2 , especially with the hydrolysis approach.…”