Noble‐Metal‐Free Ni‐MoO_x Nanoparticles Supported on BN as a Highly Efficient Catalyst toward Complete Decomposition of Hydrazine Borane

Abstract

2 (g) + 2H 2 (g)). [4] This corresponds to a theoretical gravimetric hydrogen storage capacity of 10.0 wt% for the HB-3H 2 O system, which is much higher than those of NaBH 4 -4H 2 O (7.3 wt%), NH 3 BH 3 -4H 2 O (5.9 wt%), and N 2 H 4 ·H 2 O (8.0 wt%). [5] However, in order to maximize the efficiency of N 2 H 4 BH 3 as hydrogen storage materials, the incomplete and undesired decomposition (3N 2 H 4 → 4NH 3 (g) + N 2 (g)) to ammonia (NH 3 ) must be avoided, because ammonia is toxic to fuel cell catalysts. [6] It has been reported that monometallic nanoparticles (NPs), such as Ni, Ru, and Pd, are only effective in hydrolyzing BH 3 group in HB as N 2 H 4 moiety does not participate, corresponding to a conversion of 50%. [7] Recently, some noble-metal-containing (e.g., Pt, Rh, and Pd) Ni-based heterogeneous catalysts have been developed as catalysts for high-extent dehydrogenation of HB, although the conversion and activity has been improved, the limited resources and expensive cost of noble metal still hinder their practical applications. [8] Therefore, from the viewpoint of practical application, the development of low-cost and high-efficient noble-metal-free catalysts to further improve the catalytic activity, selectivity, and conversion rate under moderate conditions is the key to realize safe and efficient hydrogen storage, thus could provide more possibilities to enter H 2 economy society. Boron nitride (BN), a material analogous to the structure of graphite, has been considered as a promising catalyst support owing to its high chemical stability, nontoxicity, and large surface area. [9] Herein, we first report a facile methodology for synthesizing BN-supported noble-metal-free Ni-MoO x /BN nanocatalyst without the help of a surfactant by a sequential impregnationreduction approach. Unexpectedly, the resultant Ni-MoO x /BN leads to the 100% conversion, 100% H 2 selectivity, and superior catalytic activity toward the dehydrogenation of HB in an alkaline solution at 323 K, with a turnover frequency (TOF) value of 600.0 h −1 , which is even better than most of the noble metal heterogeneous catalysts. [8,10] Ni-MoO x /BN composite is synthesized by a wet-chemical method as illustrated in Scheme 1. First, BN (15 mg) is dispersed in H 2 O (5 mL) through sonicating treatment. Subsequently, NiCl 2 ·6H 2 O (0.1 m, 1 mL) and Na 2 MoO 4 ·2H 2 O (0.1 m, 1 mL) aqueous solutions are impregnated to the BN Hydrazine borane (HB) has been considered as a promising hydrogen storage material due to its high hydrogen content and stability at room temperature. For the first time, a facile wet-chemical method is developed to synthesize amorphous/low crystalline noble-metal-free Ni-MoO x /BN composite as a lowcost and high-efficient catalyst for hydrogen generation from HB decomposition. The as-prepared Ni-MoO x /BN hybrid exerts 100% selective conversion and can catalyze HB complete decomposition within 5 min, corresponding to a turnover frequency (TOF) value of 600.0 h −1 at 323 K. The excellent catalytic activity may be attribut...

A Simple and Scalable Route to Synthesize CoxCu1−xCo2O4@CoyCu1−yCo2O4 Yolk–Shell Microspheres, A High‐Performance Catalyst to Hydrolyze Ammonia Borane for Hydrogen Production

“…In recent years, hydrogen production includes decomposition of chemical hydrides, hydrogen evolution reaction, photocatalysis, etc. Among these methods to produce hydrogen, one of the most effective approaches is the release of hydrogen from chemical hydrides, such as formic acid, hydrous hydrazine, hydrazine borane, an ammonia borane (AB). The generation of hydrogen by catalytic hydrolysis of AB has drawn a great deal of attention because it provides an efficient and safe way to store and generate hydrogen .…”

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

“…Over the past decades, various innovative achievements on catalysts for the hydrolysis of AB have been achieved, including single-metal, − multimetal, − metal phosphide, − metal nitride, metal oxide, − metal boride, , metal sulfide, metal hydroxide, organic molecules, and single atoms. − Noble metal (Pt, Rh, Ru, and Pd) catalysts have been proved to be markedly active for the hydrolysis of AB. − Meanwhile, non-noble metal (Ni, Co, Cu, and Fe) catalysts with relatively lower price and higher abundance have been verified with similar tremendous catalytic performance for the hydrolysis of AB. ,− Among these four kinds of non-noble metal catalysts, the Ni non-noble metal catalyst exhibits the best activity for the hydrolysis of AB, , but its relatively low catalytic activity and poor durability compared with the noble metal catalyst need to be further improved. It is worth noting that Mo-added Ni catalysts have exhibited good catalytic activities recently. , Mo itself does not have catalytic activity in the hydrolysis of AB, but it can be added to improve the dispersity, control the particle size, form an amorphous/low crystalline structure, and provide a stable support to improve the catalytic activity of the Ni-based composite catalysts. , Typically, the strategy of doping Ni with Mo to form NiMoO 4 as the precursor has been substantiated to be one of the most effective methods for plentiful significant reactions. , Nonetheless, the phase composition of annealed NiMoO 4 (in the H 2 /Ar or H 2 /N 2 reduction atmosphere at ∼673 K) is still debatable. A hybrid of Ni 4 Mo and MoO 2 was declared, , but Ni and NiO were also observed in the other studies. , Furthermore, the detailed mechanism for the hydrolysis of AB catalyzed by the NiMo non-noble catalyst is still unclear.…”

“…15,40 Mo itself does not have catalytic activity in the hydrolysis of AB, but it can be added to improve the dispersity, control the particle size, form an amorphous/low crystalline structure, and provide a stable support to improve the catalytic activity of the Ni-based composite catalysts. 41,42 Typically, the strategy of doping Ni with Mo to form NiMoO 4 as the precursor has been substantiated to be one of the most effective methods for plentiful significant reactions. 43,44 Nonetheless, the phase composition of annealed NiMoO 4 (in the H 2 /Ar or H 2 /N 2 reduction atmosphere at ∼673 K) is still debatable.…”

A Multifunctional Bioactive Glass-Ceramic Nanodrug for Post-Surgical Infection/Cancer Therapy-Tissue Regeneration

“…29-0351) and MoO 2 (JCPDS No. 65-5787) could be detected in the glass network of B-15 M and B-18M. , …”