燃料化学学报最新文献_第3页

Development of Nix/Mg1–x-MOF-74 for highly efficient CO2/N2 separation 开发用于高效 CO2/N2 分离的 Nix/Mg1-x-MOF-74

Q3 Energy

燃料化学学报

Pub Date : 2024-11-01 DOI: 10.1016/S1872-5813(24)60464-0

Xin ZHANG , Guoqiang LI , Mei HONG , Hongyan BAN , Lixia YANG , Xingchen LIU , Feng LI , Ekaterina Vladimirovna Matus , Congming LI , Lei LI

To enhance the separation selectivity of Mg-MOF-74 towards CO₂ in a CO₂/N₂ mixture, a series of Mg-MOF-74 and Ni_x/Mg_1–x-MOF-74 adsorbents were prepared by solvothermal synthesis in this paper. It was found that the adsorption capacity of Mg-MOF-74 for CO₂ could be effectively increased by optimizing the amount of acetic acid. On this basis, the bimetal MOF-74 adsorbent was prepared by metal modification. The multi-component dynamic adsorption penetration analysis was utilized to examine the CO₂ adsorption capacity and CO₂/N₂ selectivity of the diverse adsorbent materials. The results showed that Ni_0.11/Mg_0.89-MOF-74 showed a CO₂ adsorption capacity of 7.02 mmol/g under pure CO₂ atmosphere and had a selectivity of 20.50 for CO₂/N₂ under 15% CO₂/85% N₂ conditions, which was 10.2% and 18.02% higher than that of Mg-MOF-74 respectively. Combining XPS, SEM and N₂ adsorption-desorption characterization analysis, it was attributed to the effect of the more stable unsaturated metal sites Ni into the Mg-MOF-74 on the pore structure and the synergistic interaction between the two metals. Density Functional Theory (DFT) simulations revealed that the synergistic interaction between modulated the electrostatic potential strength and gradient of the material, which was more favorable for the adsorption of CO₂ molecules with small diameters and large quadrupole moment. In addition, the Ni_0.11/Mg_0.89-MOF-74 showed commendable cyclic stability, underscoring its promising potential for practical applications.

为了提高 Mg-MOF-74 对 CO2/N2 混合物中二氧化碳的分离选择性，本文采用溶热合成法制备了一系列 Mg-MOF-74 和 Nix/Mg1-x-MOF-74 吸附剂。研究发现，通过优化醋酸的用量，可有效提高 Mg-MOF-74 对 CO2 的吸附能力。在此基础上，通过金属改性制备了双金属 MOF-74 吸附剂。利用多组分动态吸附渗透分析法考察了不同吸附材料的 CO2 吸附能力和 CO2/N2 选择性。结果表明，Ni0.11/Mg0.89-MOF-74 在纯二氧化碳气氛下的二氧化碳吸附容量为 7.02 mmol/g，在 15% CO2/85% N2 条件下对 CO2/N2 的选择性为 20.50，分别比 Mg-MOF-74 高出 10.2% 和 18.02%。结合 XPS、SEM 和 N2 吸附-解吸表征分析，这归因于 Mg-MOF-74 中更稳定的不饱和金属位点 Ni 对孔隙结构的影响以及两种金属之间的协同作用。密度泛函理论（DFT）模拟显示，两种金属之间的协同作用调节了材料的静电势强度和梯度，更有利于吸附直径小、四极矩大的 CO2 分子。此外，Ni0.11/Mg0.89-MOF-74 还表现出了值得称道的循环稳定性，突显了其在实际应用中的巨大潜力。

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引用次数: 0

Research on improving carbon oxidation by fluorine doping in carbon-assisted water electrolysis for hydrogen production 碳辅助水电解制氢中通过掺氟改善碳氧化的研究

Q3 Energy

燃料化学学报

Pub Date : 2024-11-01 DOI: 10.1016/S1872-5813(24)60474-3

Qi LIU , Yanqing DOU , Zhouting GONG , Shoujun LIU , Liangyu CHEN , Yuwen TAO , Jinfang LIU , Song Yang

Faced with the constraints of the “carbon peaking and carbon neutrality goals”, the electrolysis of water for hydrogen production has received significant attention. However, high energy consumption is one of the problems hindering the industrialization of the technology. A strategy for “sacrificial anode carbon-assisted electrolysis of water for hydrogen production” is thus proposed, which uses the carbon oxidation reaction (COR) instead of the oxygen evolution reaction (OER) to achieve a significant reduction in energy consumption. In particular, F-doped biochar (denoted as F-BC-850) was prepared using a simple two-step carbonization method. The structural properties were analyzed using XRD, SEM-EDS, thermogravimetric, XPS and other characterization techniques. The structure-activity relationship was elucidated by electrochemical tests. The results showed that the energy consumption in 0.5 mol/L H₂SO₄ solution at 10 mA/cm² was 57.9% of the conventional Pt sheet electrode. Characterization results showed that HF generated by the pyrolysis of ammonium fluoride etched the biochar and formed highly active C–F bonds, which improved the oxidation performance of carbon. The addition of F species changed the carbon structure, promoted the decomposition of H₂O molecules to *OH radicals, and thus increased the adsorption ability of carbon atoms for *OH radicals. This work can provide theoretical guidelines for the efficient production of H₂ by carbon-assisted electrolysis of water and high-quality utilization of biomass.

面对 "碳峰值和碳中和目标 "的制约，电解水制氢技术受到极大关注。然而，高能耗是阻碍该技术产业化的问题之一。因此，我们提出了一种 "牺牲阳极碳辅助电解水制氢 "的策略，利用碳氧化反应（COR）代替氧进化反应（OER），从而大幅降低能耗。具体而言，采用简单的两步碳化法制备了掺杂 F 的生物炭（记为 F-BC-850）。利用 XRD、SEM-EDS、热重、XPS 等表征技术分析了其结构特性。通过电化学测试阐明了结构与活性的关系。结果表明，在 0.5 mol/L H2SO4 溶液中，10 mA/cm2 的能耗是传统铂片电极的 57.9%。表征结果表明，氟化铵热解产生的 HF 蚀刻了生物炭，形成了高活性的 C-F 键，提高了炭的氧化性能。F 物种的加入改变了碳的结构，促进了 H2O 分子分解为 *OH 自由基，从而提高了碳原子对 *OH 自由基的吸附能力。这项工作可为碳辅助电解水高效生产 H2 和生物质的高质量利用提供理论指导。

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引用次数: 0

Non-thermal plasma-catalytic reforming of tar over Ni-based catalysts 在镍基催化剂上对焦油进行非热等离子催化重整

Q3 Energy

燃料化学学报

Pub Date : 2024-11-01 DOI: 10.1016/S1872-5813(24)60475-5

Jinchao HU , Tian CHANG , Mingyan XIAO , Tian ZHANG , Xue HE

In the process of biomass gasification to produce syngas (H₂/CO), the production of tar as a by-product causes environmental pollution and hinders the development of gasification technology. The combination of non-thermal plasma and nickel-based catalysts can take advantage of the low reaction temperature of plasma and the high selectivity of catalyst to transform tar into syngas. However, carbon deposition of nickel particles in the reforming process easily causes catalyst deactivation, so designing and modifying the catalyst to improve its carbon resistance is the key to solving the catalyst deactivation problem. In this paper, the deactivation mechanism of nickel-based catalysts in the non-thermal plasma-catalytic reforming of tar system, the design and modification of catalysts to improve their carbon resistance, the types of the non-thermal plasma reactor and its tar reforming mechanism, the synergistic effects of non-thermal plasma and catalysts are reviewed. The research prospect of non-thermal plasma-catalytic reforming of tar system is also discussed. This paper provides a reference for the design and development of nickel-based catalysts in the non-thermal plasma-catalytic reforming of tar system.

在生物质气化生产合成气（H2/CO）的过程中，副产品焦油的产生会造成环境污染，阻碍气化技术的发展。非热等离子体与镍基催化剂的结合可利用等离子体的低反应温度和催化剂的高选择性将焦油转化为合成气。然而，镍颗粒在转化过程中的碳沉积容易导致催化剂失活，因此设计和改造催化剂以提高其抗碳性能是解决催化剂失活问题的关键。本文综述了焦油非热等离子体催化重整体系中镍基催化剂的失活机理、提高催化剂耐碳性的设计与改性、非热等离子体反应器的类型及其焦油重整机理、非热等离子体与催化剂的协同效应。还讨论了焦油非热等离子体催化重整系统的研究前景。本文为焦油非热等离子体催化重整系统中镍基催化剂的设计和开发提供了参考。

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引用次数: 0

In-situ growth of nickel-based catalysts on the surface of macroporous Al2O3 for CO2 methanation 在大孔 Al2O3 表面原位生长用于二氧化碳甲烷化的镍基催化剂

Q3 Energy

燃料化学学报

Pub Date : 2024-11-01 DOI: 10.1016/S1872-5813(24)60470-6

Yan YANG , Taochenxi GE , Yanan JIANG , Xian ZHANG , Yuan LIU

Macroporous catalysts often exhibit excellent mass and heat transfer properties, which can reduce pressure drop and mitigate hot spot formation during the reaction process. Addressing the issues of the active component sintering due to the strong exothermicity of CO₂ methanation and the demand for operation at high space velocities, in this work, a nickel-based catalyst with high surface area and large pore size and pore volume was prepared by in-situ growth of NiMgAl layered double hydroxide (NiMgAl-LDH) precursors on the surface of macroporous Al₂O₃. The effects of calcination temperature, reduction temperature, and space velocity on the catalyst structure and reaction performance were investigated. The results demonstrate that the catalyst phase composition can be controlled by adjusting the calcination temperature, while the reduction degree of Ni is regulated by altering the reduction temperature, which are effective in inhibiting the sintering of Ni, increasing the number of active Ni⁰ sites, and then enhancing the catalytic activity of Ni-MgO/Al₂O₃. By conducting the calcination of NiMgAl-LDH precursor at 400 °C and subsequent reduction at 650 °C, the resulted Ni-MgO/Al₂O₃ catalyst shows the highest active Ni surface area and exhibits the highest CO₂ conversion and CH₄ selectivity in the CO₂ methanation, suggesting that the surface area of metal nickel is a crucial factor for the catalytic performance of Ni-MgO/Al₂O₃. Furthermore, the Ni-MgO/Al₂O₃ catalyst performs well at a high space velocity of WHSV = 80000 mL/(g·h) and a good stability at 550 °C, where the CO₂ conversion and CH₄ selectivity keep at 54% and 79%, respectively.

大孔催化剂通常具有优异的传质和传热性能，可在反应过程中减少压降并缓解热点的形成。针对 CO2 甲烷化放热性强导致活性组分烧结以及需要在高空间速度下运行的问题，本研究通过在大孔 Al2O3 表面原位生长 NiMgAl 层状双氢氧化物（NiMgAl-LDH）前驱体，制备了一种具有高比表面积、大孔径和孔体积的镍基催化剂。研究了煅烧温度、还原温度和空间速度对催化剂结构和反应性能的影响。结果表明，通过调节煅烧温度可以控制催化剂的相组成，而通过改变还原温度可以调节 Ni 的还原程度，从而有效抑制 Ni 的烧结，增加活性 Ni0 位点的数量，进而提高 Ni-MgO/Al2O3 的催化活性。通过在 400 °C 下煅烧 NiMgAl-LDH 前驱体，然后在 650 °C 下还原，得到的 Ni-MgO/Al2O3 催化剂显示出最高的活性 Ni 表面积，在 CO2 甲烷化中表现出最高的 CO2 转化率和 CH4 选择性，这表明金属镍的表面积是 Ni-MgO/Al2O3 催化性能的关键因素。此外，Ni-MgO/Al2O3 催化剂在 WHSV = 80000 mL/(g-h) 的高空间速度下性能良好，在 550 °C 下稳定性良好，二氧化碳转化率和甲烷选择性分别保持在 54% 和 79%。

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引用次数: 0

Low-vanadium and high-activity SCR catalyst for low-temperature denitrification: Influence of vanadium precursor and surface vanadium concentration 用于低温脱硝的低钒高活性 SCR 催化剂：钒前驱体和表面钒浓度的影响

Q3 Energy

燃料化学学报

Pub Date : 2024-11-01 DOI: 10.1016/S1872-5813(24)60467-6

Xi TIAN , Peng YE , Qilong WU , Shangchao XIONG , Lina GAN , Jianjun CHEN

Nitrogen oxides (NO_x), as the main pollutants of air pollution, cause serious harm to the ecological environment and human health. SCR technology is widely used as the most effective method for treating NO_x. The core of SCR technology is SCR catalyst. The reaction temperature of traditional commercial catalysts is difficult to reach the optimal operating temperature range, so expanding the temperature window of V₂O₅/TiO₂ catalysts to the low-temperature region while reducing vanadium loading is a key issue to be solved. A series of V₂O₅/TiO₂ catalysts with different vanadium precursors and different vanadium loadings were prepared by solid-phase synthesis method. The physicochemical properties of the catalyst were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed desorption of ammonia and temperature programmed reduction of hydrogen. The denitrification activity of the catalyst was evaluated in a fixed bed reactor. The catalysts prepared with vanadyl oxalate (VOC₂O₄·xH₂O) and vanadyl acetylacetonate (VO(acac)₂) as vanadium precursors with a vanadium loading of 5% exhibited the highest denitrification activity, with a stable NO_x conversion of 100% within the temperature range of 200–350 °. Compared with the catalysts prepared with ammonium metavanadate (NH₄VO₃) and vanadyl sulfate (VOSO₄·xH₂O) as the vanadium precursors, the maximum activity temperature of VOC₂O₄-V5Ti and VO(acac)₂-V5Ti shifted towards the low-temperature region by about 150 °. Furthermore, the denitrification activity of catalyst with a low vanadium content (1%) prepared using VO(acac)₂ precursor was even higher than that of catalyst with a high vanadium content (6%) prepared using NH₄VO₃ precursor. Using VOC₂O₄ and VO(acac)₂ as vanadium precursors could effectively regulate the active sites and polymeric states on the catalysts, and promote the interaction of V atoms with different valence states to form more reductive V species (V⁴⁺), thus exhibiting excellent SCR reactivity. This study provided an effective method for the preparation of low-vanadium and high-activity denitrification catalysts at low temperatures.

氮氧化物（NOx）作为大气污染的主要污染物，对生态环境和人类健康造成严重危害。选择性催化还原（SCR）技术作为处理氮氧化物最有效的方法被广泛应用。SCR 技术的核心是 SCR 催化剂。传统商用催化剂的反应温度很难达到最佳工作温度范围，因此在降低钒负载的同时，将 V2O5/TiO2 催化剂的温度窗口扩大到低温区域是亟待解决的关键问题。本研究采用固相合成法制备了一系列不同钒前驱体和不同钒负载量的 V2O5/TiO2 催化剂。通过 X 射线衍射、X 射线光电子能谱、氨的温程解吸和氢的温程还原分析了催化剂的理化性质。在固定床反应器中对催化剂的脱硝活性进行了评估。以草酸钒（VOC2O4-xH2O）和乙酰丙酮酸钒（VO(acac)2）为钒前体制备的催化剂（钒负载量为 5%）脱硝活性最高，在 200-350 ° 的温度范围内氮氧化物转化率稳定在 100%。与以偏钒酸铵（NH4VO3）和硫酸钒（VOSO4-xH2O）为钒前体制备的催化剂相比，VOC2O4-V5Ti 和 VO（acac）2-V5Ti 的最高活性温度向低温区移动了约 150 °。此外，使用 VO(acac)2 前驱体制备的低钒含量（1%）催化剂的脱硝活性甚至高于使用 NH4VO3 前驱体制备的高钒含量（6%）催化剂。使用 VOC2O4 和 VO(acac)2 作为钒前驱体，可以有效调节催化剂上的活性位点和聚合态，促进不同价态的钒原子相互作用，形成还原性更强的钒物种（V4+），从而表现出优异的 SCR 反应活性。该研究为低温制备低钒高活性脱硝催化剂提供了一种有效的方法。

{"title":"Low-vanadium and high-activity SCR catalyst for low-temperature denitrification: Influence of vanadium precursor and surface vanadium concentration","authors":"Xi TIAN , Peng YE , Qilong WU , Shangchao XIONG , Lina GAN , Jianjun CHEN","doi":"10.1016/S1872-5813(24)60467-6","DOIUrl":"10.1016/S1872-5813(24)60467-6","url":null,"abstract":"<div><div>Nitrogen oxides (NOx), as the main pollutants of air pollution, cause serious harm to the ecological environment and human health. SCR technology is widely used as the most effective method for treating NOx. The core of SCR technology is SCR catalyst. The reaction temperature of traditional commercial catalysts is difficult to reach the optimal operating temperature range, so expanding the temperature window of V2O5/TiO2 catalysts to the low-temperature region while reducing vanadium loading is a key issue to be solved. A series of V2O5/TiO2 catalysts with different vanadium precursors and different vanadium loadings were prepared by solid-phase synthesis method. The physicochemical properties of the catalyst were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed desorption of ammonia and temperature programmed reduction of hydrogen. The denitrification activity of the catalyst was evaluated in a fixed bed reactor. The catalysts prepared with vanadyl oxalate (VOC2O4·xH2O) and vanadyl acetylacetonate (VO(acac)2) as vanadium precursors with a vanadium loading of 5% exhibited the highest denitrification activity, with a stable NOx conversion of 100% within the temperature range of 200–350 °. Compared with the catalysts prepared with ammonium metavanadate (NH4VO3) and vanadyl sulfate (VOSO4·xH2O) as the vanadium precursors, the maximum activity temperature of VOC2O4-V5Ti and VO(acac)2-V5Ti shifted towards the low-temperature region by about 150 °. Furthermore, the denitrification activity of catalyst with a low vanadium content (1%) prepared using VO(acac)2 precursor was even higher than that of catalyst with a high vanadium content (6%) prepared using NH4VO3 precursor. Using VOC2O4 and VO(acac)2 as vanadium precursors could effectively regulate the active sites and polymeric states on the catalysts, and promote the interaction of V atoms with different valence states to form more reductive V species (V4+), thus exhibiting excellent SCR reactivity. This study provided an effective method for the preparation of low-vanadium and high-activity denitrification catalysts at low temperatures.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"52 11","pages":"Pages 1696-1705"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Direct liquefaction behavior of Shenhua Shangwan coal under CO containing atmosphere 神华上湾煤在含 CO 大气环境下的直接液化行为

Q3 Energy

燃料化学学报

Pub Date : 2024-10-01 DOI: 10.1016/S1872-5813(24)60451-2

TANG Bowen, ZHANG Rui, LIU Haiyun, JIN Lijun, HU Haoquan

Direct coal liquefaction (DCL) under CO or syngas atmosphere is beneficial to reduce the cost of hydrogen production. Effects of CO on liquefaction process of Shangwan coal were investigated by comparing the liquefaction behavior in three atmospheres of CO, H_2, and N₂. Then, effects of different CO/H₂ ratios and catalysts on the liquefaction process in syngas were investigated. The results indicated that the oil yield under CO atmosphere reached 43.1%, which was 4.2% lower than that under H₂, but 10.2% higher than that under N₂. The liquefaction performance was further improved by adding the Shenhua 863 catalyst. It is analyzed that CO promoted liquefaction in two ways: water-gas shift reaction and the reaction between CO and organic structures of coal. Through characterization of the products by GC-MS and FT-IR, it was found that CO makes benzenes, aliphatics, and oxygen-containing compounds in liquefied oil simultaneously increased. The effect on functional groups and free radicals concentration in the solid products was not obvious. The experimental results under syngas showed that the highest oil yield, 57.4%, can be obtained in DCL with 20% CO syngas, and further improved by increasing moisture content of coal appropriately. In addition, the Shenhua 863 catalyst had a good catalytic effect on the liquefaction process and also water-gas shift reaction.

在 CO 或合成气气氛下进行煤直接液化（DCL）有利于降低制氢成本。通过比较 CO、H2 和 N2 三种气氛下的液化行为，研究了 CO 对上湾煤液化过程的影响。然后，研究了不同 CO/H2 比率和催化剂对合成气液化过程的影响。结果表明，CO气氛下的产油率达到43.1%，比H2气氛下低4.2%，但比N2气氛下高10.2%。加入神华 863 催化剂后，液化性能进一步提高。据分析，CO 促进液化的方式有两种：水煤气变换反应和 CO 与煤的有机结构反应。通过 GC-MS 和 FT-IR 对产物的表征发现，CO 使液化油中的苯类、脂肪族和含氧化合物同时增加。对固体产物中官能团和自由基浓度的影响并不明显。合成气条件下的实验结果表明，在使用 20% CO 合成气的 DCL 中，可获得最高的出油率（57.4%），并可通过适当提高煤的含水率进一步提高出油率。此外，神华 863 催化剂对液化过程和水煤气变换反应均有良好的催化效果。

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引用次数: 0

Mechanism of methanol synthesis from CO2 hydrogenation over Rh16/In2O3 catalysts: A combined study on density functional theory and microkinetic modeling Rh16/In2O3 催化剂氢化 CO2 合成甲醇的机理：密度泛函理论与微动力学模型的结合研究

Q3 Energy

燃料化学学报

Pub Date : 2024-10-01 DOI: 10.1016/S1872-5813(24)60460-3

WANG Yuning , GONG Jiesong , ZHOU Jiabin , CHEN Zhiyuan , TIAN Dong , NA Wei , GAO Wengui

In this study, the hydrogenation of carbon dioxide (CO₂) to methanol (CH₃OH) over Rh₁₆/In₂O₃ catalyst was studied through Density Functional Theory (DFT) and microdynamics modeling. The spontaneous dissociation mechanisms of H₂ and CO₂ adsorption at the Rh₁₆/In₂O₃ interface were investigated. The oxygen vacancies in In₂O₃ enhanced the adsorption process. Bader charge analysis revealed a marginal positive charge on Rh₁₆, elucidating the critical insights into the electronic characteristics and catalytic activity. The study established the RWGS+CO-Hydro pathway as the predominant mechanism for methanol synthesis, characterized by a sequential transformation of intermediates: CO₂*→COOH*→CO*+OH*→HCO*→CH₂O*→CH₂OH*→CH₃OH*. Furthermore, Degree of Reaction Rate Control (DRC) analysis conducted in the range of 373–873 K and 10^–2 to 10³ bar identified two principal kinetic phenomena: at lower temperature and higher pressure, the conversion of CO* + H* to HCO* significantly impacted the overall reaction rate. Conversely, at higher temperature, the step from CH₂O* + H* to CH₃O* was dominate.

本研究通过密度泛函理论（DFT）和微动力学建模研究了二氧化碳（CO2）在 Rh16/In2O3 催化剂上加氢转化为甲醇（CH3OH）的过程。研究了 Rh16/In2O3 界面吸附 H2 和 CO2 的自发解离机制。In2O3 中的氧空位增强了吸附过程。Bader 电荷分析揭示了 Rh16 上的边际正电荷，阐明了其电子特性和催化活性的重要见解。研究确定了 RWGS+CO-Hydro 途径是甲醇合成的主要机制，其特点是中间产物的顺序转化：CO2*→COOH*→CO*+OH*→HCO*→CH2O*→CH2OH*→CH3OH*.此外，在 373-873 K 和 10-2-103 bar 范围内进行的反应速率控制度（DRC）分析确定了两种主要的动力学现象：在较低温度和较高压力下，CO* + H* 向 HCO* 的转化对整体反应速率有显著影响。相反，在较高温度下，从 CH2O* + H* 到 CH3O* 的步骤占主导地位。

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引用次数: 0

Hydrogen production via steam reforming of methanol on Cu/ZnO/Al2O3 catalysts: Effects of Al2O3 precursors 在 Cu/ZnO/Al2O3 催化剂上通过甲醇蒸汽转化制氢：Al2O3 前驱体的影响

Q3 Energy

燃料化学学报

Pub Date : 2024-10-01 DOI: 10.1016/S1872-5813(24)60459-7

HUANG Min , BO Qifei , LI Juan , QIAO Jingxuan , YUAN Shanliang , ZHANG Biao , CHEN Honglin , JIANG Yi

A series of Cu/ZnO/Al₂O₃ catalysts were prepared by co-precipitation method. This research focuses on investigating the influence of different Al₂O₃ precursors on the catalyst structure through thorough structural characterization techniques. Additionally, the catalytic performance of these catalysts in methanol reforming for hydrogen production was systematically evaluated. The results indicate that the simultaneous co-precipitation of Al³⁺ with Cu²⁺ and Zn²⁺ leads to partial substitution of Cu-Zn in the basic carbonates by Al³⁺. This substitution forms a hydrotalcite-like structure and strengthens Zn-Al interactions. On the contrary, after the co-precipitation of Cu²⁺ and Zn²⁺, introducing the Al₂O₃ precursor has a positive effect on eliminating the adverse effects of Al³⁺ on Cu-Zn substitution in basic carbonates. This process promotes the Cu-ZnO interaction, facilitates the dispersion of CuO species, and enhances the reducibility of catalysts. It also improves the dispersion of Cu on the surface, and ultimately enhanced the catalytic activity. Notably, the catalyst prepared using pseudo-boehmite as the Al₂O₃ precursor exhibited the highest activity. Under the conditions of a H₂O/CH₃OH molar ratio of 1.2 and a reaction temperature of 493 K, methanol conversion reached 94.8%, and the H₂ space-time yield was 97.5 mol/(kg·h). The catalyst activity remained relatively stable after continuous operation for 25 h. Even after being heat-treated at 723 K for 10 h, the activity loss of the catalyst was only 5.37%.

通过共沉淀法制备了一系列 Cu/ZnO/Al2O3 催化剂。本研究的重点是通过全面的结构表征技术研究不同 Al2O3 前驱体对催化剂结构的影响。此外，还系统评估了这些催化剂在甲醇重整制氢过程中的催化性能。结果表明，Al3+ 与 Cu2+ 和 Zn2+ 同时共沉淀会导致碱式碳酸盐中的 Cu-Zn 被 Al3+ 部分取代。这种置换形成了类似水滑石的结构，并加强了 Zn-Al 的相互作用。相反，在 Cu2+ 和 Zn2+ 共沉淀后，引入 Al2O3 前驱体对消除 Al3+ 对碱性碳酸盐中 Cu-Zn 取代的不利影响有积极作用。这一过程促进了 Cu-ZnO 的相互作用，有利于 CuO 物种的分散，并提高了催化剂的还原性。它还改善了 Cu 在表面的分散，最终提高了催化活性。值得注意的是，用假沸石作为 Al2O3 前驱体制备的催化剂活性最高。在 H2O/CH3OH 摩尔比为 1.2 和反应温度为 493 K 的条件下，甲醇转化率达到 94.8%，H2 时空产率为 97.5 mol/（kg-h）。即使在 723 K 温度下加热 10 小时，催化剂的活性损失也仅为 5.37%。

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引用次数: 0

Cr-MIL-101 derived nano Cr2O3 for highly efficient dehydrogenation of n-hexane 提取自 Cr-MIL-101 的纳米 Cr2O3 用于正己烷的高效脱氢反应

Q3 Energy

燃料化学学报

Pub Date : 2024-10-01 DOI: 10.1016/S1872-5813(24)60458-5

LI Xiuyi, SHEN Haowei, XU Jiale, LI Chunyi

Nano Cr₂O₃ (n-Cr₂O₃) was prepared by the thermolysis of the mesoporous Cr-MIL-101, and its catalytic performance for n-hexane dehydrogenation was investigated and compared with Cr₂O₃ obtained by traditional method. It is found that dehydrogenation of n-hexane on n-Cr₂O₃ catalyst can produce n-hexenes and benzene efficiently, and the catalytic performance is related to the calcination temperature. The optimal n-hexane conversion can be obtained on n-Cr₂O₃ calcinated under 600 °C, is 40.6%, and the selectivities to n-hexenes and benzene are 20.1% and 69.3%, respectively. The conversion of n-hexane for n-Cr₂O₃ catalyst is decreased with calcination temperature increase, while the catalyst stability in dehydrogenation reaction is enhanced. n-Hexane conversion of p-Cr₂O₃-1 (obtained by precipitation method) and p-Cr₂O₃-2 (calcinating Cr(NO₃)·9H₂O directly) catalysts are very low (<7.5%), and their specific activity for n-hexane dehydrogenation are 1.5 and 1.7 g/(m²·h) respectively, lower than that of n-Cr₂O₃-600 (2.0 g/(m²·h)). The results of BET, XRD, TEM and FT-IR reveal that n-Cr₂O₃ is the nanoparticles with large specific surface area that more dehydrogenation active sites are exposed, while p-Cr₂O₃ is the large particles with extremely low surface area that few dehydrogenation active sites are presented. By contrast, industrial Cr₂O₃/Al₂O₃ catalyst possesses the highest specific activity of 2.4 g/(m²·h) due to the dispersion effect of Al₂O₃. Therefore, highly catalytic activity of n-Cr₂O₃ for n-hexane dehydrogenation is attributed to the unique properties of small particle, large specific surface area and more exposed active sites. This work not only explains the high dehydrogenation activity of nano-Cr₂O₃ derived by Cr-MIL-101, but also provides guidance for the precise design and synthesis of high-performance CrO_x-based catalyst for the dehydrogenation of alkanes.

通过热解介孔 Cr-MIL-101 制备了纳米 Cr2O3（n-Cr2O3），研究了其对正己烷脱氢的催化性能，并与传统方法制备的 Cr2O3 进行了比较。研究发现，正己烷在 n-Cr2O3 催化剂上脱氢可高效生成正己烯和苯，且催化性能与煅烧温度有关。在 600 °C 下煅烧的 n-Cr2O3 可获得 40.6% 的最佳正己烷转化率，对正己烯和苯的选择性分别为 20.1% 和 69.3%。n-Cr2O3 催化剂的正己烷转化率随煅烧温度的升高而降低，但催化剂在脱氢反应中的稳定性却有所提高。p-Cr2O3-1（通过沉淀法获得）和 p-Cr2O3-2（直接煅烧 Cr(NO3)-9H2O）催化剂的正己烷转化率很低（7.5%），其正己烷脱氢比活度分别为 1.5 和 1.7 g/（m2-h），低于 n-Cr2O3-600（2.0 g/（m2-h））。BET、XRD、TEM 和 FT-IR 的研究结果表明，n-Cr2O3 是比表面积大的纳米颗粒，暴露出较多的脱氢活性位点，而 p-Cr2O3 是比表面积极低的大颗粒，呈现出较少的脱氢活性位点。相比之下，由于 Al2O3 的分散效应，工业 Cr2O3/Al2O3 催化剂的比活度最高，达到 2.4 g/（m2-h）。因此，正氯化铬在正己烷脱氢过程中的高催化活性归因于其颗粒小、比表面积大和活性位点暴露多的独特性质。这项工作不仅解释了由 Cr-MIL-101 衍生的纳米 Cr2O3 的高脱氢活性，还为精确设计和合成用于烷烃脱氢的高性能 CrOx 基催化剂提供了指导。

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引用次数: 0

Effect of the RhnNin alloy cluster size on the catalytic performance of RhnNin/TiO2 in the conversion of syngas to ethanol RhnNin 合金团簇尺寸对 RhnNin/TiO2 在合成气转化为乙醇过程中催化性能的影响

Q3 Energy

燃料化学学报

Pub Date : 2024-10-01 DOI: 10.1016/S1872-5813(24)60454-8

ZHANG Jingjing , LING Lixia , MA Caiping , ZHANG Riguang , WANG Baojun

The direct conversion of syngas to ethanol on the Rh_nNi_n/TiO₂ (n = 1, 2, 3, 4) catalyst has been investigated by using the density functional theory (DFT) and micro-kinetic methods, in order to elucidate the regulatory mechanism of Rh_nNi_n alloy cluster size-induced metal-support interaction on the catalytic performance of Rh_nNi_n/TiO₂ in the ethanol synthesis. The results indicate that Rh₁Ni₁/TiO₂ and Rh₃Ni₃/TiO₂ can significantly enhance the conversion of CO and the formation of C–C bond and meanwhile inhibit the generation of methane. Rh₁Ni₁/TiO₂ exhibits the highest ethanol production activity and relative selectivity. The electronic property analysis results suggest that Ni atoms on the alloy clusters and Ti and O atoms on the supports transfer the most charge to the Rh atoms on the Rh₁Ni₁/TiO₂ catalyst, which displays the strongest Rh-Ni interaction on the alloy clusters as well as the strongest interaction between the alloy clusters and the TiO₂ support, endowing Rh₁Ni₁/TiO₂ with the highest catalytic activity. In addition, the Ab-initio molecular dynamics (AIMD) simulations at 525 K show that the Rh₁Ni₁/TiO₂ catalyst has high thermal stability.

利用密度泛函理论（DFT）和微观动力学方法研究了RhnNin/TiO2（n = 1, 2, 3, 4）催化剂将合成气直接转化为乙醇的过程，以阐明RhnNin合金团簇尺寸诱导的金属-支撑相互作用对RhnNin/TiO2在乙醇合成过程中催化性能的调控机制。结果表明，Rh1Ni1/TiO2 和 Rh3Ni3/TiO2 能显著提高 CO 的转化率和 C-C 键的形成，同时抑制甲烷的生成。Rh1Ni1/TiO2 的乙醇生产活性和相对选择性最高。电子性质分析结果表明，Rh1Ni1/TiO2 催化剂中合金团簇上的 Ni 原子以及载体上的 Ti 原子和 O 原子将最多的电荷转移给 Rh 原子，合金团簇上的 Rh-Ni 相互作用最强，合金团簇与 TiO2 载体之间的相互作用也最强，从而赋予 Rh1Ni1/TiO2 最高的催化活性。此外，在 525 K 下进行的 Ab-initio 分子动力学（AIMD）模拟表明，Rh1Ni1/TiO2 催化剂具有很高的热稳定性。

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引用次数: 0