Carbon-supported small Rh nanoparticles prepared with sodium citrate: Toward high catalytic activity for hydrogen evolution from ammonia borane hydrolysis

Hydrogen generation from the hydrolysis of ammonia borane (AB) over heterogeneous catalysts is essential for practical applications. Herein, efficient hydrogen evolution from AB hydrolysis over the carbon-supported Rh nanoparticles synthesized with sodium citrate (Rh/C-SC) was achieved at 25 °C. The turnover frequency value of Rh/C-SC was 336 mol H₂ (mol_Rh min)^?1, whereas that of Rh/C catalyst only yielded a value of 134 mol H₂ (mol_Rh min)^?1. The improvement of the catalytic performance of Rh/C-SC catalyst could be attributed to the small Rh particles with highly active surface areas, which were prepared by using sodium citrate as the stabilizing agent. This result indicates that sodium citrate can be applied as a useful stabilizing agent for synthesizing active metal nanoparticles, thus highly promoting the practical application of AB system for fuel cells.     

Alumina nanofiber-stabilized ruthenium nanoparticles: Highly efficient catalytic materials for hydrogen evolution from ammonia borane hydrolysis

Effective catalysts for hydrogen generation from ammonia borane (AB) hydrolysis should be developed for the versatile applications of hydrogen. In this study, ruthenium nanoparticles (NPs) supported on alumina nanofibers (Ru/Al₂O₃-NFs) were synthesized by reducing the Ru(Ш) ions impregnated on Al₂O₃-NFs during AB hydrolysis. Results showed that the Ru NPs with an average size of 2.9 nm were uniformly dispersed on the Al₂O₃-NFs support. The as-synthesized Ru/Al₂O₃-NFs exhibited a high turnover frequency of 327 mol H₂ (mol Ru min)^?1 and an activation energy of 36.1 kJ mol^?1 for AB hydrolysis at 25 °C. Kinetic studies showed that the AB hydrolysis catalyzed by Ru/Al₂O₃-NFs was a first-order reaction with regard to the Ru concentration and a zero-order reaction with respect to the AB concentration. The present work reveals that Ru/Al₂O₃-NFs show promise as a catalyst in developing a highly efficient hydrogen storage system for fuel cell applications.     

Hydrogen evolution from hydrolysis of ammonia borane catalyzed by Rh/g-C3N4 under mild conditions

Developing effective catalysts for hydrogen evolution from hydrolysis of ammonia borane (AB) is of great significance considering the useful applications of hydrogen. Herein, graphitic carbon nitride (g-C₃N₄) prepared through the simply pyrolysis of urea was employed as a support for Rh nanoparticles (NPs) stabilization. The in-situ generated Rh NPs supported on g-C₃N₄ with an average size of 3.1 nm were investigated as catalysts for hydrogen generation from the hydrolysis of AB under mild conditions. The Rh/g-C₃N₄ catalyst exhibits a high turnover frequency of 969 mol H₂· (min·mol_Rh)^?1 and a low activation energy of 24.2 kJ/mol. The results of the kinetic studies show that the catalytic hydrolysis of AB over the Rh/g-C₃N₄ catalyst is a zero-order reaction with the AB concentration and a first-order reaction with the Rh concentration. This work demonstrates that g-C₃N₄ is a useful support to design and synthesis of effective Rh-based catalyst for hydrogen-based applications.     

Mo remarkably enhances catalytic activity of Cu@MoCo core-shell nanoparticles for hydrolytic dehydrogenation of ammonia borane

Ammonia borane (AB) has been identified as one of the most promising candidates for chemical hydrogen storage. However, the practical application of AB for hydrogen production is hindered by the need of efficient and inexpensive catalysts. For the first time, we report that the incorporation of Mo into Cu@Co core-shell structure can significantly improve the catalytic efficiency of hydrogen generation from the hydrolysis of AB. The Cu_0.81@Mo_0.09Co_0.10 core-shell catalyst displays high catalytic activity towards the hydrolysis dehydrogenation of AB with a turnover frequency (TOF) value of 49.6 molH₂ mol_cat^?1 min^?1, which is higher than most of Cu-based catalysts ever reported, and even comparable to those of noble-metal based catalysts. The excellent catalytic performance is attributed to the multi-elements co-deposition effect and electrons transfer effect of Cu, Mo and Co in the tri-metallic core-shell NPs.     

Enhanced catalytic behavior of h-BN supported CuNi bimetallic catalysts in hydrolytic dehydrogenation of NH3BH3

The hydrolysis of ammonia borane (NH₃BH₃, AB) is an efficient strategy for high-purify hydrogen evolution. However, it is indispensable to develop a suitable catalyst because this reaction is kinetically infeasible at room temperature. In this work, we prepared a series of nano hexagonal boron nitride (h-BN) supported CuNi bimetallic catalysts through a facile adsorption-chemical reduction procedure. The effects of various molar ratios of Cu to Ni and CuNi loadings on AB hydrolysis were investigated in details. Benefitting from the proper porous structure, the interesting alloy effect of Cu and Ni, as well as the synergistic effect between h-BN and CuNi, 20 wt% Cu_0.5Ni_0.5/h-BN displays the highest catalytic activity among the as-prepared catalysts. Apart from satisfactory durability, the corresponding hydrogen generation rate, turnover frequency at 303 K in base solution and apparent activation energy are 2437.0 mL g^?1 min^?1, 6.33 min^?1 and 23.02 kJ mol^?1, respectively, which are very outstanding compared with many previous results. Our work not only provides a proper non-precious metal catalyst for hydrogen generation from the hydrolysis of chemical hydrogen storage materials but also offers a facile strategy for synthesizing metallic functional materials.     

Nanosizing ammonia borane with nickel – An all-solid and all-in-one approach for H2 generation by hydrolysis

Ammonia borane NH₃BH₃ (AB) and nickel (Ni) have been considered together as an all-solid and all-in-one material for H₂ generation by hydrolysis at 20–50 °C. Our novel approach, denoted Ni/AB, consists of AB nanoparticles within a Ni matrix. Upon contact with water, Ni/AB readily hydrolyzes and liberates H₂ with a turnover frequency of 13.8 mol(H₂) mol_Ni^?1 min^?1 at 43.3 °C. The apparent activation energy, determined over the temperature range 23.5–50.4 °C, is low, with 19.5 ± 4.1 kJ mol^?1. These results imply that such a Ni matrix embedding AB acts as an effective catalyst. Beyond the catalytic performance, this is the first report of the successful utilization of an all-solid and all-in-one approach for the hydrolysis of AB, and the work brings unique perspectives for one-shot catalytic systems.     

Oxygen vacancy-engaged interfacial charge transfer modulation for upgrade Rh-catalyzed hydrogen and oxygen productions

Developing efficient modulation strategies to upgrade the catalytic activity and reusability of Rh-catalyzed hydrogen evolution from ammonia borane (AB) hydrolysis are definitely profitable but remains a grand challenge. Here, we develop a stepwise activation strategy to produce highly active and reusable Rh/CoFe₂O₄-SB-H₂ with abundant oxygen vacancies and strong electronic metal-support interaction through stepwise reduction of Rh/CoFe₂O₄ precursor using sodium borohydride and H₂ as the reducing agents. Under ultrasonic irradiation, Rh/CoFe₂O₄-SB-H₂ with an ultralow Rh loading of 0.20 wt% can be utilized as an excellent catalyst for hydrogen production from room-temperature AB hydrolysis with a high turnover frequency (TOF) of 1894 min⁻¹. The TOF value could be further promoted to 15,570 min⁻¹ in the alkaline ultrasonic environment. The catalyst has a superior reusability with 75% maintaining activity of initial one in the 10^th cycle. The strong electronic metal-support interaction, rich oxygen vacancies and ultrasound irradiation promote the oxidative cleavage of the O–H bonds in attracted H₂O and thus account for high performance toward hydrogen production from AB. This catalyst can also be utilized as an active catalyst for oxygen generation from H₂O₂ decomposition. The developed strategies can be applied to upgrade the performance of other reducible metal oxides supported metal catalysts toward catalytic applications.     

Co–B nanoparticles supported on carbon film synthesized by pulsed laser deposition for hydrolysis of ammonia borane

Thin films of Carbon-supported Co–B nanoparticles were synthesized by using Pulsed Laser Deposition (PLD) and used as catalysts in the hydrolysis of Ammonia Borane (AB) to produce molecular hydrogen. Amorphous Co–B-based catalyst powders, produced by chemical reduction of cobalt salts, were used as target material for nanoparticles-assembled Co–B film catalysts preparation through PLD. Various Ar pressures (10–50 Pa) were used during deposition of carbon films to obtain extremely irregular and porous carbon support with high surface area prior to Co–B film deposition. Surface morphology of the catalyst films was studied using Scanning Electron Microscopy, while structural characterization was carried out using X-Ray diffraction. The hydrogen generation rate attained by carbon-supported Co–B catalyst film is significantly higher as compared to unsupported Co–B film and conventional Co–B powder. Almost complete conversion (95%) of AB was obtained at room temperature by using present film catalyst. Morphological analysis showed that the Co–B nanoparticles produced after the laser ablation process act as active catalytic centers for hydrolysis while the carbon support provides high initial surface area for the Co–B nanoparticles with better dispersion and tolerance against aggregation. The efficient nature of our carbon-supported Co–B film is well supported by the obtained very low activation energy (∼29 kJ (mol)⁻¹) and exceptionally high H₂ generation rate (13.5 L H₂ min⁻¹ (g of Co)⁻¹) by the hydrolysis of AB.     

Hydrogen generation by hydrolysis of ammonia borane with a nanoporous cobalt-tungsten-boron-phosphorus catalyst supported on Ni foam

In this study, quaternary cobalt-tungsten-boron-phosphorus porous particles supported on Ni foam (Co-W-B-P/Ni), which are prepared through ultrasonification-assisted electroless deposition route, have been investigated as the catalyst for hydrogen generation (HG) from hydrolysis of ammonia borane (NH₃BH₃, AB). Compared with Ni-supported binary Co-B and ternary Co-W-B catalysts, the as-synthesized Co-W-B-P/Ni shows a higher HG rate. To optimize the preparation parameters, the molar ratio of NaBH₄/NaH₂PO₂·H₂O (B/P) and the concentration of Na₂WO₄·2H₂O (W) have been investigated and the catalyst prepared with B/P value of 1.5 and W concentration of 5 g L⁻¹ shows the highest activity. The results of kinetic studies show that the catalytic hydrolysis of AB is first order with respect to the catalyst and AB concentrations. By using the quaternary catalyst with a concentration of 0.5 wt % AB, a HG rate of 4.0 L min⁻¹ g⁻¹ is achieved at 30 °C. Moreover, the apparent activation energy for the quaternary catalyst is determined to be 29.0 kJ mol⁻¹, which is comparable to that of noble metal-based catalysts. These results indicate that the Co-W-B-P/Ni is a promising low-cost catalyst for on-board hydrogen generation from hydrolysis of borohydride.     

Cobalt-nickel bimetal carbon sphere catalysts for efficient hydrolysis of sodium borohydride: The role of synergy and confine effect

Sodium borohydride exhibits great potential in the field of chemical hydrogen storage. A competent catalyst would accelerate its practical application for hydrogen utilization by enhance the efficiency of hydrogen generation from hydrolysis of sodium borohydride. Herein, a kind of highly efficient and durable synergistic Co–Ni bimetal inlaid carbon sphere catalyst (Co-NiΦC) was prepared by a co-pyrolysis method, of which the configuration of metal inlaid carbon sphere could effectively expose and anchor the active component by contrast with the capsule catalyst (Co–Ni@C) and supported catalyst (Co–Ni/C). Further, diverse cobalt-nickel contents of the Co-NiΦC catalysts were optimized to achieve the best hydrolysis performance of sodium borohydride. The structure-performance relationship of inlaid catalyst and the bimetallic synergistic mechanism were investigated by multiple characterization measurements and the density functional theory (DFT). As demonstrated, the inlaid Co-NiΦC-2 catalyst (Co/Ni molar ratio of 8/2) shows a promising catalytic activity of hydrogen generation rate up to 6364 mL_H2·min^?1·g_metal^?1, a relative low reaction activation energy of 30.3 kJ/mol as well as robust durability where it still remains about 83.4% of its initial reaction rate after the fifth cycle. The outstanding performance of the optimized catalyst may ascribe to the high dispersion, remarkable Co–Ni synergy and high stabilization of the Co–Ni nanoparticles under the confinement effect of the inlaid metal-carbon sphere configuration. This work provides an alternative avenue for the application of efficient carbon-supported bimetal catalysts in the future.     

Synthesis of polymer supported Ni (II)-Schiff Base complex and its usage as a catalyst in sodium borohydride hydrolysis

Influence of using as catalysis, Ni-Schiff Base complex which we previously synthesized [1] used to support with amberzyme oxirane resin (A.O.R.) polymer for increasing the catalytic activity in NaBH₄ hydrolysis reaction, to hydrogen generation was studied. The prepared catalyst was characterized by using SEM, XRD, BET, FT-IR analyze technique. Polymer supported Ni-Schiff Base complex catalyzed NaBH₄ hydrolysis reaction was investigated depending on concentration of NaBH₄, concentration of NaOH, temperature, percentage of Ni complex in total polymer supported Ni-Schiff Base complex and amount of catalyst factors. The maximum hydrogen production rate from hydrolysis of sodium borohydride with nickel-based complex catalyst compared to the pure nickel catalyst is increased from 772 mL H₂·g^?1 cat.·min^?1 to 2240 mL H₂ g^?1 cat.·min^?1 [1], and with supported amberzyme oxirane resin polymer this nickel based complex catalyst was increased to 13000 mL H₂·g^?1 cat.·min^?1 at 30 °C. The activation energy of complex catalyzed NaBH₄ hydrolysis reaction was found as 25.377 kJ/mol. This work also includes kinetic information for the hydrolysis of NaBH₄.     

Photoelectrocatalytic hydrolysis of ammonia borane by electrochemical deposited cuprous oxide on titanium dioxide nanotube arrays

Photoelectrocatalytic hydrolysis of ammonia borane (AB) is a promising technique for producing hydrogen gas (H₂) in the presence of an appropriate photocatalyst under light irradiation and bias. The application of cuprous oxide on titanium dioxide nanotube arrays (Cu₂O/TNA) for the photoelectrocatalytic hydrolysis of AB was studied. Cu₂O/TNA exhibited a spectral response in the ultraviolet–visible region and an onset wavelength of 600 nm. With AB in an electrolyte, Cu₂O/TNA exhibited a significant increase in its photocurrent spectral response at a bias of 0.1 V versus Ag/AgCl. The H₂ generation rate by photoelectrocatalysis (under 5-mW cm^?2 irradiation at 455 nm; bias of 0.1 V vs. Ag/AgCl) was 0.018 μmol s^?1 cm^?2, which was twice that by photocatalysis and four times those by catalysis and electrocatalysis; a Faradaic efficiency of 77% (corresponding to the oxidation reaction of AB) was also observed. Hence, Cu₂O/TNA is an efficient photoanode for photoelectrocatalytic hydrolysis of AB.     

Hydrogen generation from the hydrolysis of ammonia borane using cobalt-nickel-phosphorus (Co-Ni-P) catalyst supported on Pd-activated TiO2 by electroless deposition

Catalytically active, low-cost, and reusable transition metal catalysts are desired to develop on-demand hydrogen generation system for practical onboard applications. By using electroless deposition method, we have prepared the Pd-activated TiO₂-supported Co-Ni-P ternary alloy catalyst (Co-Ni-P/Pd-TiO₂) that can effectively promote the hydrogen release from ammonia-borane aqueous solution. Co-Ni-P/Pd-TiO₂ catalysts are stable enough to be isolated as solid materials and characterized by XRD, SEM, and EDX. They are isolable, redispersible and reusable as an active catalyst in the hydrolysis of AB. The reported work also includes the full experimental details for the collection of a wealth of kinetic data to determine the activation energy (E_a = 54.9 kJ mol⁻¹) and effects of the amount of catalyst, amount of substrate, and temperature on the rate for the catalytic hydrolysis of AB. Maximum H₂ generation rate of ∼60 mL H₂ min⁻¹ (g catalyst)⁻¹ and ∼400 mL H₂ min⁻¹ (g catalyst)⁻¹ was measured by the hydrolysis of AB at 25 °C and 55 °C, respectively.     

Cobalt nanoparticles supported on magnetic core-shell structured carbon as a highly efficient catalyst for hydrogen generation from NaBH4 hydrolysis

A novel recyclable cobalt nanocatalyst, supported on magnetic carbon with core-shell structure, was successfully synthesized by using wetness impregnation-chemical reduction method for hydrogen generation from hydrolysis of NaBH₄. The resultant nanocomposite was characterized to determine the structural and physical-chemical properties by a series of analytical techniques such as FT-IR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), SEM (scanning electron microscope), EDX (energy-dispersive X-ray spectroscopy), TEM (transmission electron microscopy), etc. The results demonstrated that amorphous cobalt nanoparticles were homogeneously surrounded on the surface of the support due to having abundant hydrophilic groups (such as aldehyde and hydroxyl groups) on the surface of carbon layer for the effective immobilization of metal ions. The supported catalyst showed superior catalytic performance towards the hydrolysis reaction of NaBH₄ at room temperature. The total rate of hydrogen generation and activation energy were calculated to be 1403 ml H₂ g_cat^?1 min^?1 and 49.2 kJ mol^?1, respectively, which were comparable to the values of most cobalt-based catalyst reported for hydrogen production from hydrolysis of NaBH₄. Additionally, reusability test revealed that the hydrogen in NaBH₄ substrate could be completely released within 25 min with a minimum hydrogen generation rate of 832 ml H₂ g_cat^?1 min^?1 even after five runs of hydrolytic reaction, implying the as-prepared Co/Fe₃O₄@C composite could be considered as a promising candidate catalyst for portable hydrogen fuel system such as PEMFC (proton exchange membrane fuel cells).     

Boron nitride supported NiCoP nanoparticles as noble metal-free catalyst for highly efficient hydrogen generation from ammonia borane

Herein, ternary metal phosphides NiCoP nanoparticles supported on porous hexagonal boron nitride (h-BN) was fabricated via hydrothermal-phosphorization strategy. The as-prepared Ni_0.8Co_1.2P@h-BN exhibited excellent catalytic performance for the hydrogen generation from ammonia borane (AB) hydrolysis, with an initial turnover frequency of 86.5 mol(H₂) mol(Ni_0.8Co_1.2P) ⁻¹ min⁻¹ at 298 K. The experimental outcome can be attributed to the synergistic effect between Ni, Co and P, as well as the strong metal-support interaction between NiCoP and h-BN. This study presents a new paradigm for supporting transition metal phosphides, and provides a new avenue to develop high performance and low cost non noble metal catalysts for hydrolysis of AB.     

Visible-light-enhanced catalytic hydrolysis of ammonia borane using RuP2 quantum dots supported by graphitic carbon nitride

Hydrolytic dehydrogenation of ammonia borane (AB) driven by efficient catalysts has attracted considerable attention and is regarded as a promising strategy for hydrogen generation. Herein, RuP₂ quantum dots supported on graphitic carbon nitride (g-C₃N₄) were successfully prepared by in-situ phosphorization, yielding a highly efficient photocatalyst toward AB hydrolysis. The catalysts were characterized by field-emission scanning electron microscopy, transmission electron microscopy, x-ray diffraction, x-ray photoelectron microscopy, inductively coupled plasma atomic emission spectroscopy, UV–visible diffuse reflectance spectroscopy and photoluminescence spectroscopy. A conventional water-displacement method was employed to record the hydrogen volume as a function of reaction time. Owing to visible-light irradiation, the initial turnover frequency of the AB hydrolysis was significantly enhanced by 110% (i.e., 134 min^?1) at room temperature. Furthermore, the apparent activation energy decreased from 67.7 ± 0.9 to 47.6 ± 1.0 kJ mol^?1. The photocatalytic hydrolysis mechanism and catalyst reusability were also investigated.     

Enhanced catalytic activity of NiM (M = Cr,Mo, W) nanoparticles for hydrogen evolution from ammonia borane and hydrazine borane

In this work, a series of Ni_1-xM_x (M = Cr, Mo, W) nanoparticles (NPs) have been successfully synthesized via a simple surfactant-aided co-reduction method and employed as highly efficient and cost effective catalysts for hydrogen generation from aqueous solution of ammonia borane (NH₃BH₃, AB) at room temperature. It is found that the as-synthesized NiM NPs (M = Cr, Mo, W) exhibit much higher catalytic performance for the hydrolysis of AB as compared to that of pure Ni NPs. In addition, among all the Ni_1-xM_x (M = Cr, Mo, W) NPs, the Ni_0.9Cr_0.1, Ni_0.9Mo_0.1, and Ni_0.8W_0.2 NPs show the highest catalytic activities with the turnover frequency (TOF) values of 10.7, 27.3 and 25.0 mol H₂ (mol metal min)^?1, respectively. Remarkably, these optimized NiM catalysts can also perform efficiently in the hydrolysis of hydrazine borane (N₂H₄BH₃, HB). The present low-cost and high-performance of the NiM catalysts system may encourage the practical application of AB and HB as the promising chemical hydrogen storage materials.     

Manganese oxide octahedral molecular sieves stabilized Rh nanoparticles for the hydrogen production from the ethylenediamine-bisborane hydrolysis

Ethylenediamine-bisborane (C₂H₁₄B₂N₂, BH₃NH₂CH₂CH₂NH₂BH₃, EDB), an important carbon derivative of ammonia-borane (AB), has come to the fore in recent years due to some disadvantages that limit the practical use of AB for the applications of hydrogen storage. EDB is a very promising chemical hydrogen storage material in the solid crystal form at room temperature, with a hydrogen content of 16.3% by weight, which decomposes rapidly at temperatures above 363 K. Despite all these superior features, studies on catalytic systems that catalyze the hydrogen production from the EDB are very few. In the present study, we report the synthesis, characterization, and application of manganese oxide octahedral molecular sieves (OMS-2) stabilized Rh nanoparticles (Rh@OMS-2) as highly efficient and reusable catalysts for the hydrogen production from the hydrolysis of EDB. The results of characterization using P-XRD, XPS, FT-IR, SEM, SEM-elemental mapping, TEM, HR-TEM, and ICP-OES disclose that Rh (0) nanoparticles were well spread on the surface of OMS-2 nanorods. Rh@OMS-2 showed a record catalytic activity in EDB hydrolysis with an initial turn-over frequency of 102.95 min^?1 (6177 h^?1) at 25 ± 0.1 °C, the highest value ever reported for the hydrolysis of EDB. In addition, the fact that the Rh@OMS-2 catalyst kept its initial activity at the end of the 7th cycle in the hydrolysis of EDB showed that the Rh@OMS-2 was reusable and stable heterogeneous catalyst in this catalytic transformation.     

Efficient hydrogen evolution from ammonia borane hydrolysis with Rh decorated on phosphorus-doped carbon

Development of supported ligand-free ultrafine Rh nanocatalysts for efficient catalytic hydrogen evolution from ammonia borane (AB) is of importance but remains a tremendous challenge. Here, ultrafine and ligand-free Rh nanoparticles (NPs) (2.19 nm in diameter) were in-situ decorated on porous phosphorus-functionalized carbon (PPC) prepared by pyrolyzing hyper-cross-linked networks of triphenylphosphine and benzene. The resultant Rh/PPC showed excellent hydrogen production activity from AB hydrolysis (Turnover frequency: 806 min⁻¹). Kinetic investigations indicated that AB hydrolysis using Rh/PPC exhibited first-order and zero-order reactions with Rh and AB concentrations, respectively. Activation energy (E_a) toward hydrogen generation from AB with Rh/PPC is as low as 22.7 kJ/mol. The Rh/PPC catalyst was recyclable and reusable for at least four times. The oxygen- and phosphorus-functional groups are beneficial for the affinity of Rh complex on the PPC surface, resulting in ultrafine and ligand-free Rh NPs with high dispersity and ability to supply abundant surface accessibility to catalytically active sites for AB hydrolysis. This study proposes a feasible approach for the synthesis of ultrafine and ligand-free metal NPs supported on heteroatom-doped carbon by using hyper-cross-linked networks.     

Synthesis of Cu@FeCo core–shell nanoparticles for the catalytic hydrolysis of ammonia borane

Non-noble Cu@FeCo core–shell nanoparticles (NPs) containing Cu cores and FeCo shells have been successfully in situ synthesized via a facile chemical reduction method. The NPs exerted composition-dependent activities towards the catalytic hydrolysis of ammonia borane (NH₃BH₃, AB). Among them, the Cu_0.3@Fe_0.1Co_0.6 NPs showed the best catalytic activity, with which the max hydrogen generation rate of AB can reach to 6674.2 mL min⁻¹ g⁻¹ at 298 K. Kinetic studies demonstrated that the hydrolysis of AB catalysed by Cu_0.3@Fe_0.1Co_0.6 NPs was the first order with respect to the catalyst concentration. The activation energy (Ea) was calculated to be 38.75 kJ mol⁻¹. Furthermore, the TOF value (mol of H₂. (mol of catalyst. min)⁻¹) of Cu_0.3@Fe_0.1Co_0.6 NPs was 10.5, which was one of the best catalysts in the previous reports. The enhanced catalytic activity was largely attributed to the preferable synergistic effect of Cu, Fe and Co in the special core–shell structured NPs.