Activity For Hydrolysis Of Ammonia Borane Research Articles

P-induced Co-based interfacial catalysis on Ni foam for hydrogen generation from ammonia borane

Co-based monolithic phosphides have caught attention due to their stability and corrosion resistance properties during the catalytic reaction. Herein, P-induced Co-based interfacial phosphides Co-CoP-NC/NF are prepared through the PH3-phosphorization. The theoretical and experimental analysis confirms the uniform growth of Co-CoP nanoparticles (NPs) with turmeric-like morphology. Co-CoP NPs (average size = 8.78 nm) express prominent interfacial interaction and a strong electronic interaction between metal sites and doped phosphorous (P). Thus, P inducing synergistically increases the number of catalytic active sites (CoP) and electronic modulation of metallic sites (Co). The optimized catalyst Co-CoP-NC/NF-2 express the excellent and the best-ranked catalytic activity for ammonia borane hydrolysis with hydrogen evolution rate (rB = 2500 mL min−1 g−1Co), turnover frequency (TOF = 600 h−1), and apparent activation energy (Ea = 30.6 kJ mol−1). This work provides a potential avenue for developing monolithic catalysts for industrial applications in the field of heterogeneous catalysis and sustainable energy.

Thermo-responsive catalysts based on bimetallic alloyed Pt-Pd supported on mesoporous silica: Controllable hydrogen generation from ammonia borane

The ultrafine and highly dispersed bimetallic Pt-Pd nanoparticles are successfully anchored on mesoporous silica nanoparticles (MSN). The [email protected] catalyst exhibits excellent catalytic performance in the hydrogen from ammonia borane (AB). When the [email protected] nanoparticles were grafted with luminescent material and smart thermo-responsive polymer, a smart catalyst could be fabricated. The smart catalyst exhibits the thermo-responsive catalytic performance and switchable luminescence. For example, the composite catalyst displays high catalytic activity in hydrolysis of AB at 25 °C. However, it shows much lower catalytic activity when the temperature increases to 35 °C. The smart catalysts could be potentially applied in the self-protection device of dehydrogenation. When the system of dehydrogenation is under high temperature environment, the smart composite catalyst could automatically restrain the production of H2 for the purpose of safety.

Universal low-temperature oxidative thermal redispersion strategy for green and sustainable fabrication of oxygen-rich carbons anchored metal nanoparticles for hydrogen evolution reactions

A simple and green low-temperature oxidative thermal redispersion strategy was developed for obtaining well-distributed Rh, Ru, Ir NPs on oxygen-rich mesoporous carbon with considerable activity toward hydrogen evolution compared with the counterpart without any pre-treatment. • Universal low-temperature oxidative thermal redispersion strategy was developed. • The strategy benefits for well-defined metal NPs anchored on oxygenated carbons. • As-formed AC was a universal carrier for selected Pt group metal (Ru, Rh, Ir) NPs. • Rh/C-300A-350H had the highest HER activity for AB hydrolysis and water splitting. • The small Rh NPs with electron-rich sites contributed to the high HER performance. Supported metal nanoparticles (MNPs) have shown great promise in catalytic hydrogen evolutions because of the highly efficient utilization of metal atoms, while the low binding strength between MNPs and supports results in the agglomeration of MNPs into larger particles, considerably decreasing the catalytic efficiency. Herein, we smartly develop a universal, green, and sustainable low-temperature oxidative thermal redispersion strategy to fabricate metal oxide precursors and subsequently well dispersing and stabilizing MNPs (M = Rh, Ru, Ir) over oxygenated carbons (Mesoporous carbon, Ketjen black, and Vulcan carbon), which can be utilized as efficient catalysts for hydrogen production from ammonia borane (AB) hydrolysis and hydrogen evolution reaction (HER). Such flexible modulation strategy enables the formation of oxidized metal species on oxygenated carbons, which is the key to synthesize ultrasmall MNPs against sintering and agglomeration during the reduction process. Attributing to the innately structural/componential/surficial superiorities, the optimal Rh/C-300A-350H exhibits the highest catalytic activity toward hydrogen evolution from AB hydrolysis and HER with turnover frequencies of 3308/5040 min −1 in aqueous/basic solutions and an overpotential of 29 mV at 10 mA cm −2 in 1.0 M KOH, respectively. With the similar activation mechanism for dissociation of O–H bond in H 2 O, the highly dispersed Rh NPs with ultrafine sizes and electronic metal-support interaction are responsible for the excellent catalytic activity toward the hydrogen evolution reactions. This study presents an extremely facile and sustainable modulation strategy for increasing the adhesion of MNP catalysts on oxygenated carbons for catalytic applications.

Tuning catalytic performance by controlling reconstruction process in operando condition

Catalytic activity of nanostructured materials are closely tied with structure, thus developing nanomaterials with processable structures has arisen as a new strategy for designing high active catalysts. In this work we report the realization of controllable structural evolution of NiAu-based materials in operando conditions. The structure evolution of NiAu catalysts at atomic scale has been characterized by ex-situ scanning transmission electron microscopy. The catalytic activity for ammonia borane hydrolysis has promoted for 4.4-fold after adapting structural evolution. The catalytic stability has increased for 16-fold of maintaining 75% activity. This work provides inspiration for emerging catalysts design based on bimetallic nanoparticles with both high performance and durability in a catalytic reaction system.

From Ru nanoparticle-encapsulated metal–organic frameworks to highly catalytically active Cu/Ru nanoparticle-embedded porous carbon

High-temperature pyrolysis of Ru nanoparticle-encapsulated MOF (Ru@HKUST-1) afforded ultrafine Cu/Ru nanoparticle-embedded porous carbon composites (Cu/Ru@C), which show high catalytic activity for ammonia borane hydrolysis.

Facile Synthesis of Three-Dimensional Pt-TiO2 Nano-networks: A Highly Active Catalyst for the Hydrolytic Dehydrogenation of Ammonia-Borane.

Three-dimensional (3D) porous metal and metal oxide nanostructures have received considerable interest because organization of inorganic materials into 3D nanomaterials holds extraordinary properties such as low density, high porosity, and high surface area. Supramolecular self-assembled peptide nanostructures were exploited as an organic template for catalytic 3D Pt-TiO2 nano-network fabrication. A 3D peptide nanofiber aerogel was conformally coated with TiO2 by atomic layer deposition (ALD) with angstrom-level thickness precision. The 3D peptide-TiO2 nano-network was further decorated with highly monodisperse Pt nanoparticles by using ozone-assisted ALD. The 3D TiO2 nano-network decorated with Pt nanoparticles shows superior catalytic activity in hydrolysis of ammonia-borane, generating three equivalents of H2 .

Bimetallic RuCo and RuCu catalysts supported on γ-Al 2O 3. A comparative study of their activity in hydrolysis of ammonia-borane

Bimetallic-based RuCo and RuCu catalysts, supported on γ-Al 2O 3 (1.5 wt% Ru as theoretical value), were synthesized by polyol method. Ru, Co, and Cu acetylacetonates were used as precursors and ethylene glycol as reducing agent. The as-synthesized catalysts were characterized by SEM, TEM, XRD and XPS, and tested in ammonia-borane (NH 3BH 3) hydrolytic dehydrogenation at variable amount of catalyst (10–30 wt%), concentration of NH 3BH 3 (1.0–0.65 M), and temperatures (50–65 °C). The reactions were monitored by volumetric (inverted burette) and spectroscopic methods ( 11B and 11B{ 1H} NMR). It was found that the best bimetallic catalysts are those having a molar ratio Ru:Co and Ru:Cu of 1:1 such as RuCo > RuCu ∼ Ru. They, i.e. RuCo and RuCu, consist of nanosized spherical particles of Ru 0Co(OH) 2 and Ru 0Cu 0, respectively. Kinetic investigation highlights similar rate laws with activation energies of 47 kJ mol −1 and 52 kJ mol −1, respectively, and, for both, reaction orders of 1 versus both the NH 3BH 3 and the catalytic free sites concentrations. 11B and 11B{ 1H} NMR investigation confirmed ( i) a more effective NH 3BH 3 hydrolytic dehydrogenation in the presence of RuCo catalyst even though a loss of activity after the first run was observed for both catalysts, and ( ii) a rapid NH 3BH 3 hydrolysis with initial formation of B(OH) 4 −, which besides favors equilibriums of formation of polyborates. These results are reported and the reaction mechanism discussed herein.