ACS Applied Nano Materials
·
2024
·
IF 5.3
Baoshan Teng,Chunhui Ma,Jiayu Chen,Yunlai Zhang,Baohuan Wei,Maohai Sang,Hui Wang,Yuhan Sun
Ammonia is recognized as the best carrier for hydrogen storage and transportation. Nanomaterial catalysts have eminent catalytic activity for ammonia decomposition. However, the preparation of low-loading, high-activity noble metal atomically dispersed nanometer ammonia decomposition catalysts and their reaction mechanisms remain obscure. In this work, we report the synthesis of a stable ruthenium (Ru) atomically dispersed catalyst with oxygen-rich defects achieved through hydrogen etching of the support CeO2NR nanorods. The oxygen defects result in the catalyst exhibiting a favorable low-temperature catalytic activity and an exceedingly high atom utilization rate for ammonia decomposition. The hydrogen production rate from ammonia decomposition per unit mass of Ru is as high as 2446 mmol H2 gRu–1 min–1 at 1 bar, 450 °C, and gas hour space velocity = 12,000 mL gcat–1 h–1. In this case, the highly dispersed Ru provided enough active sites, while the oxygen defects of the catalyst enhanced the electron transfer tunnel between Ru and the nanorod support under a Schottky contact model. The detailed mechanism of oxygen defects for improving the catalytic performance of ammonia decomposition was studied by DFT modeling. Thus, this work provides a promising strategy to improve the catalytic efficiency of an atomically dispersed Ru nanocatalyst.
研究领域:
材料科学
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催化化学
·
理论化学
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Zhixian Bao,Dekang Li,Zhiheng Wang,Yuxin Wen,Lijun Jin,Haoquan Hu
The lack of detailed functions of different REMs in NH 3 decomposition to H 2 makes the efficient modified catalysts not rationally be designed though many REMs-modified catalysts have been reported. In this work, the 10Ni/A 1 Mg 4 O α (A = La, Ce, and Y) and 10Ni/MgO, in which supports were synthesized by the sol–gel method and Ni was loaded by the wet-impregnate method, were comparatively investigated to reveal the effect of REMs against NH 3 decomposition reaction. The presence of REMs enhanced the activity of 10Ni/A 1 Mg 4 O α and decreased the activation energy as greatly as by half compared to 10Ni/MgO. The produced H 2 in situ has little impact on the activity of 10Ni/A 1 Mg 4 O α , among which Ce has the most excellent H 2 desorption ability. The intrinsic activity of catalysts was improved better by Ce and Y than La and the best Ni particle size is around 6 nm according to TOF, though the Ni particle is the smallest (4.9 nm) in 10Ni/La 1 Mg 4 O α . The surface structure of catalysts was tuned by doping REMs, forming a solid solution and some defects (oxygen vacancies), which enhanced the interaction between active metal and support with obvious electron transfer from support to Ni obtaining a better Ni dispersion and making NiO easier to be reduced. Additionally, the catalysts doped by La or Ce possess more oxygen vacancy due to the changes of La 2 O 2 CO 3 and the valence of Ce, exhibiting stronger basic sites and better N 2 desorption capacity. The study offers a promising strategy for utilizing appropriate or multiple REMs to synthesize effective catalysts effectively for catalyzing NH 3 decomposition in the future.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Yu Qiu,Enkang Fu,Feng Gong,Rui Xiao
Ammonia is a prospective fuel for hydrogen storage and production, but its application is limited by the high cost of the catalysts (Ru, etc. ) to decompose NH 3 . Decomposing ammonia using non-precious Ni as catalysts can therefore improve its prospects to produce hydrogen. This work proposes several Ni/MgAl 2 O 4 with the support properties tuned and investigates the support effect on the catalytic performance. Ni/MgAl 2 O 4 -LDH shows high NH 3 conversion (∼88.7%) and H 2 production rate (∼1782.6 mmol g −1 h −1 ) at 30,000 L. kg −1 h −1 and 600 °C, which is 1.68 times as large as that of Ni/MgAl 2 O 4 -MM. The performance remains stable over 30 h. The characterizations manifest that the high specific surface area of Ni/MgAl 2 O 4 -LDH can introduce highly dispersed Ni on the surface. Kinetics analysis implies promoted NH 3 decomposition reaction and alleviated H 2 poisoning for Ni/MgAl 2 O 4 -LDH. A roughly linear relationship is obtained by fitting the curves of dispersed Ni on the surface vs the reaction orders regarding H 2 and NH 3 . This indicates that enhanced NH 3 decomposition performance can be ascribed to the strengthened NH 3 decomposition reaction and weakened H 2 poisoning by the highly dispersed Ni on the MgAl 2 O 4 -LDH surface. This work provides an opportunity to develop highly active and cost-effective catalysts to produce hydrogen via NH 3 decomposition.
研究领域:
化学工程
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能源科学
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2017
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IF 2.429
Yanran XUN,Xinxin HE,Han YAN,Ziwang GAO,Zhao JIN,Chunjiang JIA
In this paper, a series of Fe- and Co-doped lanthanum (hydr)oxides catalysts were prepared by a simple coprecipitation-hydrothermal method. The as-prepared catalysts were characterized with various techniques including powder X-ray diffraction (XRD), N 2 adsorption/desorption, inductively coupled plasma (ICP) and transmission electron microscopy (TEM). The Fe-based catalysts exhibited consecutive phase changes of amorphous FeO x →FeLaO 3 →Fe 2 N under different stages (as-prepared→calcination→ammonia decomposition reaction); as for Co-based catalysts, the phase transformation followed a sequence of Co(OH) 2 → Co 3 O 4 →metallic Co. It was revealed that Fe 2 N and metallic Co were most probably the active crystalline phase respectively for Fe- and Co-based catalysts in the decomposition of ammonia.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
MOLECULES
·
2025
·Vol. 30
·期 11
·2301
·
IF 4.6
Wenying Wu,Wenhao Yao,Yitong Liu,Senliang Xi,Teng Zhang
Ammonia is a promising hydrogen storage material because it is easy to store and decompose into COX-free hydrogen. A Ru-based catalyst exhibits good catalytic performance in ammonia decomposition, and enhancing the interaction between the Ru atoms and the support is an important way to further improve its catalytic activity. In this study, CeO2was prepared by calcination using a cerium-based metal–organic framework (MOF) as the precursor, and the number of oxygen vacancies on the surface of CeO2was regulated by hydrogen reduction. The XPS and Raman results showed that abundant oxygen vacancies were formed on the surface of these CeO2, and their number increased with an increase in the reduction time. The Ru/CeO2-4 h catalyst, using CeO2reduced for 4 h as the support, exhibited good catalytic activity in ammonia decomposition, reaching 98.9% ammonia conversion and 39.74 mmol gcat−1min−1hydrogen yield under the condition of GHSV = 36,000 mL gcat−1h−1at 500 °C. The XAFS results demonstrated that Ru was stably anchored with oxygen vacancies on the surface of CeO2via Ru-O-Ce bonds. Density functional theory calculations further showed that these bondings lower the reaction energy barrier for N-H bond cleavage, thereby significantly enhancing the catalytic activity.
研究领域:
材料科学
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化学工程
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能源技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2025
·
IF 8.3
Qing Zhang,Boyun Gao,Fan Sun,Huijiang Huang,Yan Xu,Feng Gao,Yan Wang,Yujun Zhao
This study reports a stable catalyst for NH 3 decomposition to hydrogen. The precursor of SiO 2 @NP was prepared by hydrothermal method, and the hydrothermal treatment of spherical SiO 2 results in etching of SiO 2 and the formation of nickel phyllosilicate, which greatly increase specific surface area of the catalyst. Ru is loaded onto the SiO 2 @NP by incipient wetness impregnation, forming the catalyst 1Ru/SiO 2 @NP. At a gas hourly space velocity (GHSV) of 30,000 mL NH3 (g × h) −1 and 650 °C, the conversion of ammonia over 1Ru/SiO 2 @NP reaches 98%. Furthermore, the catalyst maintains excellent stability during a period of 210 h at 600 °C. To investigate the origination of activity and stability, various characterizations have been used. In its reduced form, Ni and Ru stay metallic, and Ru–Ni interactions are realized. Both high specific surface area and Ru–Ni interactions allow the generation of small metallic particles that are resistant to sintering during reaction process, thus improving the activity and stability of the catalyst. This study provides new insights and references for the preparation of efficient and stable catalysts for NH 3 decomposition.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ChemistrySelect
·
2025
·Vol. 10
·期 16
·e202405818
·
IF 2
Gideon Kofie,Yin Fengxiang,Xu Rongji,Wu Qinxi
Graphical This study examines NdCoO 3 perovskite catalysts synthesized via solution combustion using citric acid for ammonia decomposition. The best performing catalyst 1.25:1NdCoO 3 -700 exhibits 96% conversion at 550 °C and a hydrogen production rate of 30 mmol·g⁻¹·min⁻¹. High basicity, optimized pore structure, and surface properties enhance the performance highlighting NdCoO 3 ’s potential for efficient hydrogen production. The decomposition of ammonia to produce hydrogen requires an efficient catalyst to lower the energy demand for this reaction. This study investigates the performance of NdCoO 3 in enhancing ammonia decomposition for hydrogen production. The NdCoO 3 perovskite is synthesized using the solution-combustion method with citric acid as fuel. The performance evaluation of the catalysts is conducted in a fixed-bed reactor. The catalysts are characterized by establishing the relationship between structure and activity. A fuel-to-metal ratio of 1.25:1 and a calcination temperature of 700 °C result in a catalyst with favorable physicochemical attributes. The catalyst 1.25:1NdCoO 3 -700 is obtained, which achieves 96% ammonia conversion at 550 °C, with a hydrogen generation rate of 30.6 mmolgcat −1. min −1 , making it the most active catalyst with an apparent activation energy ( E a ) of 64.47 KJ mol −1 . The surface analysis reveals that variations in surface basicity and favorable porosity affected the activity of the 1.25:1NdCoO 3 -T catalysts. The fuel-to-metal ratio and the calcination temperature are key factors influencing the activity of the NdCoO 3 catalyst.
研究领域:
材料科学
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催化化学
·
能源转化
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2024
·
IF 5.2
Hongming Liu,Junhui Liang,Jiaxin Li,Yuhui Du,Hangning Chen,Chenhao Du,Liuqi Wang,Yincheng Li,Yuexiang Huang,Da Chen
While ammonia serves as a carbon-free hydrogen carrier, addressing challenges in hydrogen energy storage and transportation, the present technology for thermocatalytic ammonia decomposition encounters constraints owing to elevated decomposition temperatures. Alkali metal promoters have been demonstrated to effectively lower the reaction temperature. However, their precise role in the process of ammonia dehydrogenation remains not fully understood. Herein, we investigated the impact of alkali metals by incorporating various base treatments (with (i.e., KOH) or without alkali metals (i.e., NH3·H2O)) during the deposition process. The results indicate that compared to samples without alkali metal treatment, catalysts with added alkali metals (5 wt % Ru/CeO2-NP(KOH)) show a 16.7% improvement in ammonia decomposition efficiency and a 5.54 mmol gcat–1 min–1 increase in hydrogen production rate under the same test conditions (500 °C, gas hourly space velocity (GHSV) of 30,000 mL gcat–1 h–1). This phenomenon may be attributed to the dual promotion of alkali metal K in regulating both vacancy defects and metal active sites. The regulatory mechanism of alkali metal activity proposed by us not only provides a better understanding of the specific role of alkali metals in the reaction process but also holds significant implications for guiding the design of novel catalysts.
研究领域:
催化化学
·
能源材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2023
·
IF 5.3
Chengliang Wu,Yun Jin,Yiyi Fan,Ngie Hing Wong,Jaka Sunarso,Xiuxia Meng,Naitao Yang
Hydrogen (H2) production by ammonia (NH3) decomposition offers a solution to the energy problem. In this work, an MXene (titanium carbide, Ti3C2TX) membrane was successfully synthesized by depositing it onto the anodic aluminum oxide (AAO) substrate using vacuum-assisted filtration. Then, a membrane reactor supported by MXene was developed for H2 production by NH3 decomposition. The MXene membrane reactor could achieve an H2 permeance of 2.85 × 10–7 mol m–2 s–1 Pa–1 and an H2/N2 selectivity of 20 at 773.15 K. Next, a Ni-La/γ-Al2O3 catalyst prepared by impregnation and sintering was added to catalyze the NH3 decomposition process. The experimental results showed that the reactor could achieve a 99% NH3 conversion at 773.15 K, i.e., 9% higher than that of the packed catalytic reactor (without membrane). A mathematical model of the membrane reactor was developed to explain the experimental results. The calculated activation energies (Ead) of the MXene membrane for H2 and N2 permeances were 64.95 and 69.53 kJ mol–1, respectively. The activation energy (Ear) of NH3 decomposition was 147.8 kJ mol–1. Both the experimental and modeling results showed that the membrane reactor could enhance NH3 conversion and promote the production of high-purity H2.
研究领域:
材料科学
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化学工程
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Shigang Li,Xiaohui Liu,Yong Guo,Yanqin Wang
Ammonia is considered as a potential hydrogen carrier as its high hydrogen content. Hydrogen release still presents challenges due to the lack of efficient catalyst. In this work, we report a Ni@SiO 2 catalyst prepared through a sol–gel method, which displays satisfied catalytic activity and remarkable long-term stability. The origination of activity and stability has been investigated carefully by various characterizations. The strong interaction between nickel species and silica species is responsible for the excellent performance via generating small nickel particle and hindering the sintering of nickel during the high temperature reaction condition. This study offers novel insights into the design and preparation of highly efficient catalysts for ammonia decomposition to produce hydrogen.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Ze-Wei Wu,Jing Xiong,Cun-Wen Wang,Yuan-Hang Qin
Although supported Ni is generally considered the most active non-noble metal catalyst for decomposing NH 3 to produce CO x -free H 2 , its activity is not sufficient. Herein, supporting high-loading Ni on SBA-15 is explored to alleviate the low intrinsic activity issue of Ni. SBA-15 supports with tunable textual properties are synthesized to support Ni catalyst for NH 3 decomposition. Characterization shows that Ni catalyst with a loading close to 40 wt% supported on SBA-15 with the largest specific surface area (Ni/SBA-15-80) exhibits a NH 3 decomposition performance much better than those reported on other Ni-based NH 3 decomposition catalysts, resulting from its favorable textural properties and high Ni loading. In addition, Ni/SBA-15-80 shows excellent catalytic stability, with no activity degradation over an 80-h NH 3 decomposition test. This work reveals the importance of textural properties of support and Ni loading to NH 3 decomposition performance and can provide a new idea for synthesizing high-performance NH 3 decomposition catalysts.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2025
·
IF 9.5
Liu Hongming,Xin Yao,Jiaxin Li,Junhui Liang,Huayu Chen,Wei Zhao,Chen Hangning,Du Chenhao,Yuexiang Huang,Da Chen
Thermocatalytic ammonia decomposition for hydrogen production is regarded as an effective strategy to tackle the challenges of hydrogen storage and transport. Most current strategies focus on the adsorption-evolution mechanism to balance kinetic barriers in rate-determining steps, thereby reducing reaction temperature. Herein, we report a strategy to promote the kinetics of ammonia decomposition by altering the reaction pathway through lattice nitrogen mediation. The results indicate that using a nitrogen-containing graphene-like g-C3N4 as the support, the ammonia decomposition efficiency and hydrogen production rate are improved by 72.11 % and 80.11 mmol gcat-1 min-1, respectively, compared to nitrogen-free graphene as the support (5 wt% Ru/Gr-AR), under conditions of only 20 mg catalyst, 500 °C, and a gas hourly space velocity (GHSV) of 18,000 mL gcat-1 h-1. Under these conditions, the hydrogen production rate (99.45 mmol gcat-1 min-1) is significantly higher than that of previously reported Ru-based catalysts, and a 100-hour test further confirms its excellent stability. In addition, by proposing a nitrogen-cycle pathway model for ammonia decomposition potentially mediated by lattice nitrogen, we can not only provide a plausible explanation for the enhanced catalytic activity of nitrogenous catalyst, but also provide important guidance for the design of new catalysts.
研究领域:
催化化学
·
能源材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）