共查询到20条相似文献,搜索用时 15 毫秒
1.
《International Journal of Hydrogen Energy》2019,44(31):16548-16556
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 (Ea) 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. 相似文献
2.
《International Journal of Hydrogen Energy》2023,48(7):2640-2651
Alloy catalyst has been widely studied and used for hydrolytic dehydrogenation of ammonia borane (NH3BH3, AB) with excellent catalytic performance due to the synergistic effect of bimetal. Herein, a series of Rh1-xCox/Ni@Ni–N–C catalysts were prepared by an impregnation reduction method. The optimized Rh0.75Co0.25/Ni@Ni–N–C catalyst exhibited good catalytic performance with turnover frequency of 223.08 molH2 molcat?1 min?1 at 303 K, but decreased the catalytic performance compared with Rh/Ni@Ni–N–C. According to the XPS and Raman analysis, the RhCo alloy nanoparticles could be loaded at the defect position of Ni@Ni–N–C, and the Co nanoparticles occupied the intercalation between Rh and the defective site of the carrier, which could weaken the catalytic activity of AB hydrolysis. Based on the above research, we proposed the catalytic mechanism of the activation of the RhCo–H species. This work provides a new strategy for designing alloy-supported nano-catalysts. 相似文献
3.
《International Journal of Hydrogen Energy》2022,47(64):27598-27607
In this work, cobalt–tungsten–boron nanoparticles (Co–W–B) have been successfully deposited on foam Ni to manufacture thin-film catalysts by electroless plating technique and applied in hydrogen generation from ammonia borane (NH3BH3) hydrolysis. Physicochemical properties of Co–W–B nanoparticles are characterized by XRD (Powder X–ray diffraction), SEM (Scanning electron microscopy), and EDS (Energy dispersive X–ray spectroscopy). It is observed that Co–W–B showed irregular spherical structure on the surface of foam Ni substrate. An increase of depositional pH value in the preparation process leads to the change of particle size. When the pH value is equal to 11.5, as-synthesized Co–W–B exhibits the smaller particle size, which suggests that depositional pH value has directly impacted the nucleation and growth of catalysis particles. The optimized Co–W–B catalyst displays higher catalytic activity toward NH3BH3 hydrolysis with a specific rate of hydrogen generation of 12933.3 mL min?1·g?1 at room temperature. Moreover, the lower apparent activation energy of 47.3 kJ mol?1 is achieved. Compared with previously reported catalysts, the as-obtained catalytic performance is situated at the better rank. Moreover, the reusability has been investigated under the mild NH3BH3 hydrolysis conditions. It reveals that as-fabricated thin-film Co–W–B maintains excellent durability after five cycles. A possible mechanism for the released hydrogen from NH3BH3 hydrolysis using Co–W–B catalyst has been proposed. 相似文献
4.
Fangyuan Qiu Yiling Dai Li Li Changchang XuYanan Huang Chengcheng ChenYijing Wang Lifang JiaoHuatang Yuan 《International Journal of Hydrogen Energy》2014
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 Cu0.3@Fe0.1Co0.6 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 Cu0.3@Fe0.1Co0.6 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 Cu0.3@Fe0.1Co0.6 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. 相似文献
5.
《International Journal of Hydrogen Energy》2019,44(55):29255-29262
In this work, poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium nanoparticles (NPs) supported on bamboo leaf-derived porous carbon (Ru/BC) has been synthesized via a one-step procedure. The structure and morphology of the as-synthesized samples were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), scanning electron microscope (SEM) and transmission electron microscope (TEM). As a catalyst for hydrogen generation from the hydrolysis of ammonia-borane (AB, NH3BH3) at room temperature, Ru/BC stabilized with 1 mg of PVP exhibited high activity (TOF = 718 molH2·molRu−1·min−1) and low activation energy (Ea = 22.8 kJ mol−1). In addition, the catalyst could be easily recovered and showed fairly good recyclability with 55.6% of the initial catalytic activity retained after ten experimental cycles, which confirmed that PVP could stabilize the Ru NPs and prevent their agglomeration on BC surface. Our results suggest that PVP-stabilized Ru/BC is a highly efficient catalyst for the hydrolysis of AB. 相似文献
6.
《International Journal of Hydrogen Energy》2019,44(41):23267-23276
The hydrolysis of ammonia borane (NH3BH3) is recognized as an efficient way of hydrogen generation if it can be effectively catalyzed. In this work, a series of cobalt–molybdenum–boron (Co–Mo–B) nanoparticles (NPs) on copper (Cu) foil are introduced as catalysts for NH3BH3 hydrolysis by electroless deposition method. The influence of the depositing pH value on the catalytic property is investigated by adjusting the pH value ranged from 10.5 to 12.0. By optimizing the value to 11, the ultrafine Co–Mo–B NPs with the grain size around 4.3 nm show the best catalytic property for NH3BH3 hydrolysis. The hydrogen generation rate reaches 5818.0 mL·min−1·g−1 when the hydrolysis temperature is 298 K. The thermodynamic tests show that the lower activation energy (Ea) is estimated to be 59.3 kJ·mol−1. It can be found that the catalytic property in this work overtakes that of partial non-precious metal NPs, and is even better than some precious metal NPs previously reported. The hydrolysis reaction of NH3BH3 catalyzed by ultrafine Co–Mo–B NPs is a non-spontaneous process. In addition, the cycling ability of the ultrafine Co–Mo–B NPs is also studied and the results demonstrate that the catalyst is a recyclable one toward the hydrolysis of NH3BH3 under mild reaction conditions. 相似文献
7.
《International Journal of Hydrogen Energy》2019,44(49):26773-26782
In this study, we report the results of a kinetic study on the hydrogen (H2) generation from the hydrolysis of ammonia borane (NH3BH3) catalyzed by Platinum supported on carbon nanotube-graphene hybrid material (Pt/CNT-G). Synthesized catalyst was characterized by TGA, XRD, CP-OES, TEM and SEM-EDX techniques. Characterization studies have shown that the CNT-G hybrid support material provides desired distribution of the Pt particles on the support material. The effect of various parameters such as catalyst loading, reaction temperature, effect of NaOH and the effect of NH3BH3 concentration are also determined. Experimental results showed that the Pt/CNT-G catalyst exhibited high catalytic activity on NH3BH3 hydrolysis reaction to release H2. It has been found that Pt/CNT-G catalyst shows low activation energy of 35.34 kJ mol−1 for hydrolysis reaction of NH3BH3. Pt/CNT-G catalyst also exhibited high catalytic activity with turnover frequency (TOF) of 135 (molH2/molcat.min). Therefore, the synthesized Pt/CNT-G catalyst is a potential candidate for enhanced H2 generation through NH3BH3 hydrolysis. 相似文献
8.
Jialu Shen Weifeng Chen Guo Lv Zihan Yang Jiaying Yan Xiang Liu Zhongxu Dai 《International Journal of Hydrogen Energy》2021,46(1):796-805
Recently, effective hydrogen (H2) evolution upon hydrolysis of different hydrogen storage materials has received much attention. Herein, graphene quantum dots-transition metal nanoparticles (GQDs-TMNPs), with high dispersibility and activity, have been successfully applied in the hydrolysis of both NH3BH3 (AB) and NaBH4 for the first time. GQDs-RhNPs, GQDs-RuNPs, and GQDs-PtNPs are very effective in the hydrolysis of AB and the turnover frequencies (TOFs) can achieve to as high as 656, 384, and 281 molH2·molcat?1 min?1, respectively. Moreover, the synergistic effect between GQDs and TMNPs is explored, and the mechanisms of catalytic hydrolysis of AB and NaBH4 by GQDs-TMNPs are proposed. This work not only paves the way for the development of GQDs-TMNPs nanocatalysts for the different hydrogen storage materials, but also further advances the understanding of the synergistic effects between GQDs and TMNPs. 相似文献
9.
Xiaoling Shan Jing DuFangyi Cheng Jing LiangZhanliang Tao Jun Chen 《International Journal of Hydrogen Energy》2014
We report the preparation of Ni3B and carbon-supported Ni3B (denoted as Ni3B/C) nanoparticles, and their catalytic performance for hydrogen generation from hydrolytic dehydrogenation of ammonia borane (NH3BH3, AB). Ni3B and Ni3B/C were prepared via a chemical reduction and crystallization in tetraethylene glycol solution. The obtained Ni3B catalysts are in well-defined crystalline state and Ni3B/C catalysts have a high dispersion in the carbon. The hydrogen generation measurement shows that the carbon-supported Ni3B presents enhanced catalyst activity during hydrolytic dehydrogenation of AB. Among the as-prepared Ni3B/C catalysts, Ni3B/C with 34.25 wt% Ni3B loading displays the best catalytic activity, delivering a high hydrogen release rate of 1168 mL min−1 g−1 and the lower activation energy of 46.27 kJ mol−1. The kinetic results show that the hydrolysis is a first-order reaction in catalyst concentration, while it is a zero-order in AB concentration. Furthermore, the Ni3B/C is a recyclable catalyst under mild reaction conditions, indicating that the carbon-supported Ni3B is a promising catalyst for AB hydrolytic dehydrogenation. 相似文献
10.
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 (Ea = 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. 相似文献
11.
Wei Cheng Yumei Peng Yi Wang Weidong Jiang Yan Long Guangyin Fan 《International Journal of Hydrogen Energy》2021,46(2):2204-2212
Hydrogen evolution from ammonia borane (AB) hydrolysis is of great importance considering the ever-increasing demand for green and sustainable energy. However, the development of a facile and efficient strategy to construct high-performance catalysts remains a grand challenge. Herein, we report an amino-group and space-confinement assisted strategy to fabricate Rh nanoparticles (NPs) using amino-functionalized metal-organic-frameworks (UiO-66-NH2) as a NP matrix (Rh/UiO-66-NH2). Owing to the coordination effect of amino-group and space-confinement of UiO-66-NH2, small and well-distributed Rh NPs with a diameter of 3.38 nm are successfully achieved, which can be served as efficient catalysts for AB hydrolysis at room temperature. The maximum turnover frequency of 876.7 min?1 is obtained by using the Rh/UiO-66-NH2 with an optimal Rh loading of 4.38 wt% and AB concentration of 0.2 M at 25 °C, outperforming most of the previously developed Rh-based catalysts. The catalyst is also stable in repetitive cycles for five times. The high performance of this catalyst must be ascribed to the structural properties of UiO-66-NH2, which enable the formation of small and well-dispersed Rh NPs with abundant accessible active sites. This study provides a simple and efficient method to significantly enhance the catalytic performance of Rh for AB hydrolysis. 相似文献
12.
《International Journal of Hydrogen Energy》2014,39(35):20031-20037
NiAgPd nanoparticles are successfully synthesized by in-situ reduction of Ni, Ag and Pd salts on the surface of carbon. Their catalytic activity was examined in ammonia borane (NH3BH3) hydrolysis to generate hydrogen gas. This nanomaterial exhibits a higher catalytic activity than those of monometallic and bimetallic counterparts and a stoichiometric amount of hydrogen was produced at a high generation rate. Hydrogen production rates were investigated in different concentrations of NH3BH3 solutions, including in the borates saturated solution, showing little influence of the concentrations on the reaction rates. The hydrogen production rate can reach 3.6–3.8 mol H2 molcat−1 min−1 at room temperature (21 °C). The activation energy and TOF value are 38.36 kJ/mol and 93.8 mol H2 molcat−1 min−1, respectively, comparable to those of Pt based catalysts. This nanomaterial catalyst also exhibits excellent chemical stability, and no significant morphology change was observed from TEM after the reaction. Using this catalyst for continuously hydrogen generation, the hydrogen production rate can be kept after generating 6.2 L hydrogen with over 10,000 turnovers and a TOF value of 90.3 mol H2 molcat−1 min−1. 相似文献
13.
Serdar Akbayrak Yalçın Tonbul Saim Özkar 《International Journal of Hydrogen Energy》2021,46(27):14259-14269
Herein, we report the use of tungsten(VI) oxide (WO3) as support for Rh0 nanoparticles. The resulting Rh0/WO3 nanoparticles are highly active and stable catalysts in H2 generation from the hydrolysis of ammonia borane (AB). We present the results of our investigation on the particle size distribution, catalytic activity and stability of Rh0/WO3 catalysts with 0.5%, 1.0%, 2.0% wt. Rh loadings in the hydrolysis reaction. The results reveal that Rh0/WO3 (0.5% wt. Rh) is very promising catalyst providing a turnover frequency of 749 min?1 in releasing 3.0 equivalent H2 per mole of AB from the hydrolysis at 25.0 °C. The high catalytic activity of Rh0/WO3 catalyst is attributed to the reducible nature of support. The report covers the results of kinetics study as well as comparative investigation of activity, recyclability, and reusability of colloidal(0) nanoparticles and Rh0/WO3 (0.5 % wt. Rh) catalyst in the hydrolysis reaction. 相似文献
14.
《International Journal of Hydrogen Energy》2020,45(35):17164-17173
The development of inexpensive and high performing catalysts for ammonia borane (NH3BH3) hydrolysis is crucial for hydrogen production. In our research, a high-performance plate-like Cu2O–CoO nanocomposite catalyst for NH3BH3 hydrolysis has been developed for the first time. In the hydrolytic reaction, both Cu2O and CoO are separately inactive, while Cu2O–CoO nanoplates show a high turnover frequency of 34.1 molhydrogen min−1 molcat−1, which is attributed to the synergistic effect between Cu2O and CoO. It is interesting to discover that the induction time for the hydrolytic reaction is reduced to null when a small amount of Cu2O is introduced into CoO. The reaction kinetics of NH3BH3 hydrolysis catalyzed by Cu2O–CoO is also investigated. This work may provide other researchers some valuable insights into designing inexpensive and synergistic catalysts with enhanced catalytic activity for NH3BH3 hydrolysis for hydrogen production. 相似文献
15.
Jiaqin Chen Min Hu Mei Ming Caili Xu Yi Wang Yun Zhang Jiangtao Wu Daojiang Gao Jian Bi Guangyin Fan 《International Journal of Hydrogen Energy》2018,43(5):2718-2725
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 (molRh min)?1, whereas that of Rh/C catalyst only yielded a value of 134 mol H2 (molRh 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. 相似文献
16.
《International Journal of Hydrogen Energy》2023,48(61):23540-23549
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 10th 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. 相似文献
17.
《International Journal of Hydrogen Energy》2020,45(14):7881-7891
Ammonia borane (H3N·BH3, AB) is one of the promising hydrogen storage materials due to high hydrogen storage capacity (19.6% wt), high stability in solid state as well as in solution and nontoxicity. The methanolysis of AB is an alternative way of releasing H2 due to many advantages over the hydrolysis such as having high stability against self releasing hydrogen gas. Here we review the reports on using various noble or non-noble metal(0) catalysts for H2 release from the methanolysis of AB. Ni(0), Pd(0), and Ru(0) nanoparticles (NPs), stabilized as colloidal dispersion in methanol, are highly active and long lived catalysts in the methanolysis of AB. The catalytic activity, lifetime and reusability of transition metal(0) NPs show significant improvement when supported on the surface of solid materials. The supported cobalt, nickel, copper, palladium, and ruthenium based catalysts are quite active in H2 release from the methanolysis of AB. Rh(0) NPs are highly active catalysts in releasing H2 from the methanolysis of AB when confined within the void spaces of zeolite or supported on oxide nanopowders such as nanosilica, nanohydroxyapatite, nanoalumina or nanoceria. The oxide supported Rh(0) NPs can provide high activity with turnover frequency values as high as 218 min−1 and long lifetime with total turnover values up to 26,000 in generation of H2 from the methanolysis of AB at 25 °C. When deposited on carbon the bimetallic AgPd alloy nanoparticles have the highest activity in releasing H2 through the methanolysis of AB. 相似文献
18.
Xiaowei Chen Feng Yuan Qinfen Gu Yingbin Tan HuaKun Liu Shixue Dou Xuebin Yu 《International Journal of Hydrogen Energy》2013
A combined strategy via mixing Mg(BH4)2·6NH3 with ammonia borane (AB) is employed to improve the dehydrogenation properties of Mg(BH4)2·6NH3. The combined system shows a mutual dehydrogenation improvement in terms of dehydrogenation temperature and hydrogen purity compared to the individual components. A further improved hydrogen liberation from the Mg(BH4)2·6NH3–6AB is achieved with the assistance of ZnCl2, which plays a crucial role in stabilizing the NH3 groups and promoting the recombination of NHδ+?HBδ−. Specifically, the Mg(BH4)2·6NH3–6AB/ZnCl2 (with a mole ratio of 1:0.5) composite is shown to release over 7 wt.% high-pure hydrogen (>99 mol%) at 95 °C within 10 min, thereby making the combined system a promising candidate for solid hydrogen storage. 相似文献
19.
A new hydrogen storage system NaZn(BH4)3?2NH3-nNH3BH3 (n = 1–5) was synthesized via a simple ball milling of NaZn(BH4)3?2NH3 and NH3BH3 (AB) with a molar ratio from 1 to 5. Dehydrogenation results revealed that NaZn(BH4)3?2NH3-nAB (n = 1–5) showed a mutual dehydrogenation improvement in terms of significant decrease in the dehydrogenation temperature and preferable suppression of the simultaneous evolution of by-products (i.e. NH3, B2H6 and borazine) compared to the unitary compounds (NaZn(BH4)3?2NH3 and AB). Specially, the NaZn(BH4)3?2NH3-4AB sample is shown to reach the maximum hydrogen purity (99.1 mol %) and favorable dehydrogenation properties rapidly releasing 11.6 wt. % of hydrogen with a peak maximum temperature of 85 °C upon heating to 250 °C. Isothermal dehydrogenation results revealed that 9.6 wt. % hydrogen was liberated from NaZn(BH4)3?2NH3-4AB within 80 min at 90 °C. High-resolution in-situ XRD and Fourier transform infrared (FT-IR) measurements indicated that the significant improvements on the dehydrogenation properties in NaZn(BH4)3?2NH3-4AB can be attributed to the interaction between the NH3 group from NaZn(BH4)3?2NH3 and AB in the mixture, resulting a more activated Hδ+···−δH combination. The research on the reversibility of the spent fuels of NaZn(BH4)3?2NH3-4AB showed that regeneration could be partly achieved by reacting them with hydrazine in liquid ammonia. These aforementioned favorable dehydrogenation properties demonstrate the potential of the combined systems to be used as solid hydrogen storage material. 相似文献
20.
《International Journal of Hydrogen Energy》2023,48(48):18245-18256
Ammonia borane (AB, NH3BH3) hydrolysis is an effective way to safely generate hydrogen. However, a suitable catalyst is indispensable because the hydrolytic reaction cannot take place kinetically at room temperature. In this work, CuNi alloy nanoparticles are immobilized on porous graphitic carbon nitride (g-C3N4) with a facile adsorption-chemical reduction method. Benefiting from the hierarchical porous structure of the support, the interesting alloy effect of Cu and Ni, as well as the synergistic effect between g-C3N4 and the CuNi alloys, the optimal Cu0·7Ni0.3/g-C3N4 catalyst displays excellent catalytic performance in AB hydrolysis, such as high turnover frequency (2.08 min−1, at 303 K), low apparent activation energy (23.58 kJ mol−1), and satisfactory durability. The results verify that the optimal catalyst has particular potential in hydrogen energy utilization due to the advantages such as the facile preparation procedure, low cost and excellent catalytic behavior. 相似文献