Heterostructured Ni/NiO Nanoparticles on 1D Porous MoO_x for Hydrolysis of Ammonia Borane

Abstract

The hydrolysis of AB has been regarded as a kind of secure and efficient method for hydrogen generation. However, the development of economical and stable catalysts with high catalytic activities remains a bottleneck for realizing further industrial application of AB. Herein, high-loading heterostructured Ni/NiO nanoparticles with different Ni/NiO weight ratios anchored on one-dimensional porous MoO x nanorods (denoted as Ni/NiO@MoO x ) have been synthesized and introduced into the hydrolysis of AB for the first time. The Ni/NiO@MoO x -50H catalyst (synthesized under the reduction atmosphere of 50% H2/50% Ar) with an optimal Ni/NiO weight ratio (73.96/26.04) exhibits an excellent catalytic activity for the hydrolysis of AB with the turnover frequency (TOF) value reaching 86.29 molH 2 molNi –1 min–1 at 298 K, which is one of the highest TOF values among the reported non-noble metal catalysts. In addition, on account of high Ni loading weight (29.15 wt %), the hydrogen generation rate of Ni/NiO@MoO x -50H achieves 10,478 mL·min–1 g–1 (35,947 mL·min–1 gNi –1), overtaking most values both in noble and non-noble metal catalysts for the hydrolysis of AB. The bridging effect of NiO steadily connects the Ni and MoO x carrier and promotes great durability of Ni/NiO@MoO x -50H, of which the catalytic activity exhibits not significant degradation in the fifth cycle. The catalysis originated from the metal/metal oxide (Ni/NiO@MoO x ) provides a novel insight into the catalyst design, preparation, and application for chemical hydrogen storage systems.

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

“…Figure a shows the high-resolution XPS of Ni 2p, which could be divided into the typical components of Ni 0 , oxidized Ni species, and Ni satellite. As shown in Figure a, for freshly prepared catalysts, the observed XPS peaks are located at 853.0–853.6 eV corresponding to the Ni 0 , ,, and this peak is 0.3–0.9 eV higher than the standard metallic Ni; this result is consistent with the reported literature . This blue shift of the Ni XPS peak in the 10Ni/CNTs is possibly related to the electron transfer from Ni to CNTs support, indicating the modulation of the electronic structure of Ni by CNTs, which is evidence of the strong metal–support interaction between Ni and CNTs substrate.…”

“…As shown in Figure b, for 10Ni30Mo 2 C/CNTs, the peak observed at 228.6 eV is assigned to the presence of Mo 2+ species in the β-Mo 2 C form. The other bands at BE values of 229.5 and 233.0 eV are attributed to the oxidation states of Mo 4+ and Mo 6+ , which, respectively, are derived from the MoO 2 and MoO 3 phases due to the partial surface oxidation of Mo x C when exposed to air . In the case of 10Ni30MoC/CNTs, besides the peak of Mo 4+ species (229.5 eV), other two peaks with Mo 3d 5/2 binding energies of 231.4 and 233.0 eV are assigned to Mo 5+ and Mo 6+ , respectively.…”

Cu/Ni-NiOx Nanoparticles Distributed on Graphene as Catalysts for the Methanolysis of Ammonia Borane to Produce Hydrogen

“…Many studies had tried to use transition-metal NPs to partially or completely replace noble-metal NPs. − But it is still necessary to enhance the activity and stability of transition-metal NPs because they tend to be oxidized and aggregate into larger particles. − Researchers had proposed a variety of solutions, and the most commonly used method was the loading method. The carriers included G, , C 3 N 4 , , porous metal–organic framework (MOF), − silica, , carbons, , PVP, α-MoC, MoO x , TiO 2 , etc. Among transition-metal NPs, because the Cu element is abundant in the earth’s crust and Cu NPs have excellent catalytic properties, Cu and Cu-based NPs have attracted extensive interest. , However, Cu NPs are extremely unstable under environmental conditions and their instability limited their practical applications .…”

Combined Effect of Functionality and Pore Size on Dehydrogenation of Ammonia Borane via Its Nanoconfinement in Polyacrylamide-Grafted Organically Modified Mesoporous Silica

“…In addition, the hydrogen desorption property of NaBH 4 was impacted due to the presence of different ions. He et al 33 reported development of a stable and economical catalysis system for AB hydrolysis. They utilized Ni/NiO nanoparticles and porous MoOx nanorods (denoted as Ni/ NiO@MoOx).…”