Molecular Catalysis最新文献

Light alkanes dehydrogenation over silica supported gallium catalysts 二氧化硅支撑镓催化剂上的轻烷脱氢反应

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-16 DOI: 10.1016/j.mcat.2024.114646

Yury A. Agafonov, Oleg L. Eliseev

The present work is devoted to the studies of Ga/Silica catalysts in the paraffins dehydrogenation of natural gas - propane and ethane to produce valuable products - olefins and hydrogen. The gallium oxide supported on silica gel (2–10 %wt. of Ga) have been studied using XRD, TPR-H₂ and STEM/EDS methods, it has been shown that the dispersion of gallium oxide over the silica surface is very effective, the support actively reacts with a gallium salt to form surface particles that are more easily reduced than pure gallium oxide. Under steady and no-stationary state the negative effect of oxidative pre-treatment and the addition of CO₂ to the reaction mixture on catalytic activity was detected. On the contrary, pre-treatment of the catalysts in hydrogen (at 650–700 °C) or CO addition to the reaction mixture was accompanied by an increase in their propane dehydrogenation activities and stabilities at 600 °C. In the ethane dehydrogenation conditions (650 to 700 °C) catalysts is effective treated by hydrogen during the experiment. At 700 °C, the Ga/Silica activity may even increase during ethane dehydrogenation. By TPR-H₂ it was observed that with an increase in the temperature of pre-treatment of Ga/Silica in hydrogen from 650 to 700 °C, the proportion of oxidized Ga-containing phase significantly decreases.

本研究致力于镓/二氧化硅催化剂在天然气（丙烷和乙烷）石蜡脱氢过程中的应用研究，以生产有价值的产品（烯烃和氢）。使用 XRD、TPR-H2 和 STEM/EDS 方法研究了硅胶上的氧化镓（镓含量为 2-10%wt.），结果表明氧化镓在硅胶表面的分散非常有效，支撑物会与镓盐积极反应，形成比纯氧化镓更容易还原的表面颗粒。在稳定和非稳定状态下，氧化预处理和在反应混合物中加入二氧化碳对催化活性有负面影响。相反，在氢气（650-700 °C）中对催化剂进行预处理或在反应混合物中加入 CO 的同时，催化剂的丙烷脱氢活性和在 600 °C 下的稳定性都有所提高。在乙烷脱氢条件下（650 至 700 °C），催化剂在实验过程中经过了有效的氢气处理。在 700 °C 的乙烷脱氢过程中，镓/二氧化硅的活性甚至会增加。通过 TPR-H2 可以观察到，随着镓/二氧化硅在氢气中的预处理温度从 650 ℃ 升高到 700 ℃，氧化的含镓相的比例明显降低。

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引用次数: 0

Proper NCoordination improves catalytic activity of graphene edge anchored Pt single atom for conversion of methane and carbon dioxide to acetic acid 适当的数控配位提高了石墨烯边缘锚定铂单原子将甲烷和二氧化碳转化为醋酸的催化活性

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-16 DOI: 10.1016/j.mcat.2024.114688

Baoyu Huang , Xiaomei Zhao , Yang Ma , Zhengjun Fang

The reaction of directly converting CH₄ and CO₂ into acetic acid has a wide and important application in the chemical industry. In this work, we carried out systematically computational chemistry study on the catalytic performance of the single Pt atom catalyst anchored at the edge of N-doped graphene for the direct co-conversion of CH₄ and CO₂ to acetic acid based on density functional theory (DFT) calculations. The DFT calculation results show the catalytic activity of single Pt atom is significantly tuned by the local N-atom coordination. The Pt-N₁C exhibits the best catalytic performance of CH₄ and CO₂ conversion with a low rate-determining free energy barrier of 0.69 eV The microkinetic modeling shows that the TOF of CH₃COOH on Pt-N₁C catalyst reaches 7.63×10² s⁻¹ at 600 K and 2 bar Further analysis shows that the adsorption strength of reactant CH₄ and CO₂ is linearly correlated with the energy level of d_xy orbital center of Pt atom. A moderate adsorption strength of CH₄ and CO₂ over the Pt-N₁C leads to easier activation of methane and migration of H and CH₃ during the conversion reaction.

将 CH4 和 CO2 直接转化为醋酸的反应在化学工业中有着广泛而重要的应用。在这项工作中，我们基于密度泛函理论（DFT）计算，对锚定在掺杂 N 的石墨烯边缘的单铂原子催化剂的催化性能进行了系统的计算化学研究。DFT 计算结果表明，单个铂原子的催化活性受局部 N 原子配位的影响很大。微动模型显示，在 600 K 和 2 bar 条件下，CH3COOH 在 Pt-N1C 催化剂上的 TOF 达到 7.63×102 s-1 进一步分析表明，反应物 CH4 和 CO2 的吸附强度与铂原子 dxy 轨道中心的能级成线性关系。Pt-N1C 对 CH4 和 CO2 的吸附强度适中，因此在转化反应过程中甲烷更容易活化，H 和 CH3 更容易迁移。

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引用次数: 0

On the Mechanism of Acrylate and Propionate Silyl Esters Synthesis by Ruthenium-Catalyzed Coupling of CO2 with C2H4 in the Presence of Hydrosilanes: Combined Experimental and Computational Investigations 在氢硅烷存在下，通过钌催化 CO2 与 C2H4 偶联合成丙烯酸酯和丙酸酯硅酯的机理：实验与计算相结合的研究

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-16 DOI: 10.1016/j.mcat.2024.114660

Kana Kunihiro , Thayalan Rajeshkumar , Laurent Maron , Svetlana Heyte , Sébastien Paul , Thierry Roisnel , Jean-François Carpentier , Evgueni Kirillov

The upcycling of CO₂ to value-added chemicals using catalytic approaches constitutes a challenge in the topical area of sustainable development and use of renewable resources. We report herein on a Ru(II)-catalyzed reductive carboxylation of ethylene in the presence of hydrosilane (Et₃SiH) affording acrylate and propionate silyl esters. Upon using high-throughput screening (HTS) and batch-reactor techniques, some promising catalyst systems incorporating 1,4-bis(dicyclohexylphosphino)butane (DCPB) as ligand, namely monohydrido-chloro complex Ru(H)(Cl)(CO)(DCPB)(PPh₃) (Ru-2) or dihydride complex Ru(H)₂(CO)(DCPB)(PPh₃) (Ru-5), were identified among a few others. Detailed mechanistic studies involving the isolation of a Ru(II)-acrylate intermediate and computational investigations unveiled the possible operational mechanism leading to the construction of the acrylate platform from CO₂ and ethylene. The selectivity toward the desired silyl esters is affected by side-processes (mainly CO₂ hydrosilylation, ethylene hydrosilylation and dehydrogenative coupling of ethylene with hydrosilane) and could be improved by varying the substrates’ concentrations (CO₂/ethylene/hydrosilane ratios), while the acrylate vs. propionate selectivity depends on the processes producing in situ H₂, which is responsible for the reduction of the acrylate C=C double bond. In particular, a marked role of water on the selectivity was rationalized as a potential H₂ source when used in combination with hydrosilane. A better selectivity towards the production of triethylsilyl acrylate could be achieved using dihydride complex Ru-5 as discrete precatalyst (up to 47% vs. 15% with Ru-1/DCPB), in line with the mechanistic studies.

利用催化方法将二氧化碳转化为高附加值化学品是可持续发展和可再生资源利用这一主题领域的一项挑战。我们在此报告了在氢硅烷 (Et3SiH) 存在下催化 Ru(II) 的乙烯还原羧化反应，生成丙烯酸酯和丙酸硅酯。通过使用高通量筛选（HTS）和批量反应器技术，发现了一些以 1,4-双（二环己基膦）丁烷（DCPB）为配体的有前景的催化剂体系，即一水-氯络合物 Ru(H)(Cl)(CO)(DCPB)(PPh3) (Ru-2) 或二水络合物 Ru(H)2(CO)(DCPB)(PPh3) (Ru-5) 等。详细的机理研究包括分离 Ru（II）-丙烯酸酯中间体和计算研究，揭示了从二氧化碳和乙烯构建丙烯酸酯平台的可能运行机制。对所需硅酯的选择性受副过程（主要是二氧化碳氢硅烷化、乙烯氢硅烷化和乙烯与氢硅烷的脱氢偶联）的影响，可通过改变底物浓度（二氧化碳/乙烯/氢硅烷比率）来改善，而丙烯酸酯对丙酸酯的选择性取决于原位产生 H2 的过程，H2 负责还原丙烯酸酯的 C=C 双键。特别是，当水与氢硅烷结合使用时，水作为一种潜在的 H2 源，对选择性的显著作用得到了合理的解释。使用二酐络合物 Ru-5 作为离散的前催化剂，可以获得更高的丙烯酸三乙基硅酯生产选择性（高达 47%，而 Ru-1/DCPB 为 15%），这与机理研究结果一致。

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引用次数: 0

Spiro-linked hanging group cobalt phthalocyanine for CO2-to-methanol electrocatalysis unveiled by grand canonical density functional theory 通过大规范密度泛函理论揭示用于 CO2-甲醇电催化的螺环悬挂基钴酞菁

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-16 DOI: 10.1016/j.mcat.2024.114689

Beibei Tang , Chao Ma , Zhiyuan Xu , Qi Zhang

Heterogeneous cobalt phthalocyanine (CoPc) is one of the few favorable molecular catalysts for the electrocatalytic reduction of carbon dioxide to methanol. In-plane substituent modification of planar conjugated phthalocyanine ligands is a key way to establish the structure-activity relationship and enhance the catalytic performance of cobalt phthalocyanines. While steric hanging substituents inspired by efficient enzymes' catalytic architectures are prevalent in metalloporphyrin systems, their application in metal phthalocyanines remains underexplored. Herein, we carried out a systematic constant potential theoretical study on heterogeneous hanging group substituted CoPc electrocatalytic carbon dioxide reduction reaction. Notably, a phenol-based hanging group-modified tetra amino cobalt phthalocyanine was found to have excellent activity and selectivity for the methanol production. Intriguingly, the hanging group substituent connects to the ligand through a spirocyclic structure (rather than the conventional C-N single bond), which can reduce spatial steric hindrance and maintain hydrogen bonding. The phenolic H atoms in the hanging group form effective hydrogen bonds with the O atoms in the key structures of *CHO and *CH₂O, resulting in a strong stabilizing effect that facilitates the selectivity-determining *CO → *CHO and rate-determining *CHO → *CH₂O over a wide potential range. Our findings offer a theoretically effective hanging group substituent for metal phthalocyanine catalysts, broadening the scope and complexity of substituent design.

异质酞菁钴（CoPc）是电催化将二氧化碳还原为甲醇的少数几种有利分子催化剂之一。平面共轭酞菁配体的平面内取代基修饰是建立钴酞菁的结构-活性关系并提高其催化性能的关键方法。受高效酶催化结构启发而产生的立体悬挂取代基在金属卟啉体系中非常普遍，但它们在金属酞菁中的应用仍未得到充分探索。在此，我们对悬挂基团取代 CoPc 的异相电催化二氧化碳还原反应进行了系统的恒电位理论研究。值得注意的是，我们发现一种基于苯酚的悬挂基团修饰的四氨基钴酞菁在甲醇生产中具有优异的活性和选择性。有趣的是，悬挂基团取代基通过螺环结构（而不是传统的 C-N 单键）与配体连接，这可以减少空间立体阻碍并保持氢键。悬挂基团中的酚类 H 原子与 *CHO 和 *CH2O 关键结构中的 O 原子形成有效的氢键，从而产生强大的稳定作用，在较宽的电位范围内促进决定选择性的 *CO → *CHO 和决定速率的 *CHO → *CH2O。我们的发现为金属酞菁催化剂提供了一种理论上有效的悬挂基取代基，拓宽了取代基设计的范围和复杂性。

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引用次数: 0

Development of active Pd-only three-way catalysts: The balance between surface composition and oxygen vacancies of ceria-zirconia support 开发活性纯钯三元催化剂：氧化锆铈载体表面成分与氧空位之间的平衡

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-15 DOI: 10.1016/j.mcat.2024.114682

Zixuan Zheng , Xinyi Yin , Zhiwei Zhou , Linmei Wang , Wei Wang , Shanshan Li , Jianli Wang , Yaoqiang Chen

CeO₂-based catalysts have attracted widespread attention in gasoline vehicle exhaust purification, and their catalytic performance is often intimately associated with the supports used. In this work, a series CeO₂-ZrO₂ (CZ) supports with varying composition and phase structure (with or without partial κ-Ce₂Zr₂O₈ structure) have been employed for Pd-only three-way catalysts (TWCs), and the corresponding activities were evaluated. It was found that for catalysts without κ-Ce₂Zr₂O₈ structure, the activity is positively related with the content of CeO₂ in CZ due to the increased Pd-O-Ce interfaces. However, as the formation of κ-Ce₂Zr₂O₈ structure is accompanied by the increased surface oxygen vacancies but decreased surface Ce-O_x species, for catalysts with κ-Ce₂Zr₂O₈ structure, there exists a balance between the reasonable concentration of oxygen vacancies and surface Ce-O_x species in determining the corresponding activities. Among these catalysts, only the Pd-only TWC with medium content of CeO₂ and partial κ-Ce₂Zr₂O₈ structure (Pd/κMC) exhibits superior activity than that in the same composition but without κ-Ce₂Zr₂O₈ structure (Pd/MC). This may be associated with the obviously increased surface oxygen vacancies introduced in κMC, which could compensate the slight decrease of its surface Ce-O_x species to stabilize the supported Pd species in smaller size and higher oxidation states. This finding enhances the understanding of support effects to rationally design efficient heterogeneous catalysts.

基于 CeO2 的催化剂在汽油车尾气净化领域受到广泛关注，其催化性能通常与所使用的载体密切相关。在这项工作中，一系列具有不同组成和相结构（具有或不具有部分 κ-Ce2Zr2O8 结构）的 CeO2-ZrO2 (CZ) 催化剂被用于纯钯三相催化剂 (TWC)，并对相应的活性进行了评估。研究发现，对于无 κ-Ce2Zr2O8 结构的催化剂，由于 Pd-O-Ce 界面的增加，其活性与 CZ 中 CeO2 的含量呈正相关。然而，由于κ-Ce2Zr2O8 结构的形成伴随着表面氧空位的增加和表面 Ce-Ox 物种的减少，因此对于具有κ-Ce2Zr2O8 结构的催化剂来说，氧空位和表面 Ce-Ox 物种的合理浓度之间存在着平衡，从而决定了相应的活性。在这些催化剂中，只有具有中等含量 CeO2 和部分 κ-Ce2Zr2O8 结构的纯 Pd TWC（Pd/κMC）比具有相同组成但不含 κ-Ce2Zr2O8 结构的 TWC（Pd/MC）具有更高的活性。这可能与 κMC 中引入的表面氧空位明显增加有关，这可以弥补其表面 Ce-Ox 物种的轻微减少，从而使支撑的钯物种稳定在较小的尺寸和较高的氧化态。这一发现加深了人们对支撑效应的理解，有助于合理设计高效的异相催化剂。

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引用次数: 0

Emerging molecular sieve regulation strategy for the adsorption and catalysis: Silicon hydroxyl engineering 用于吸附和催化的新兴分子筛调节策略：硅羟基工程

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-15 DOI: 10.1016/j.mcat.2024.114667

Zehao Pei , Zhenghao Feng , Zhitian Yao , Yongming Luo , Jichang Lu

As a widely used aluminosilicate material, molecular sieves are modified to enhance performance according to the requirements of different practical working conditions. One of the main functional groups, the silicon hydroxyl group, is crucial to the unique chemical characteristics and adsorption capacity of molecular sieves, because of silicon hydroxyl group has inherent hydrogen bonding, which can give molecular sieves more adsorption and catalytic sites. Moreover, silicon hydroxyl groups are crucial for regulating the performance of molecular sieves and operate as a channel for the insertion of extra active compounds. Various regulating tactics include grafting ionic liquids and organic molecules, are utilized to create silicon hydroxyl nests to either directly or indirectly anchor active metals, and forming silicon hydroxyl groups to engage in adsorption and catalysis. The classification methods and characterization techniques of silicon hydroxyl groups have been summarized, and the introduction methods and applications in regulating the performance of molecular sieves have been reviewed. The key factors that need attention in regulating silicon hydroxyl groups have been analyzed. Finally, the development trend for the performance and application of silicon hydroxyl groups controlled molecular sieves in the future was discussed.

分子筛作为一种应用广泛的硅酸铝材料，可根据不同实际工况的要求进行改性以提高性能。硅羟基是分子筛的主要官能团之一，它对分子筛的独特化学特性和吸附能力至关重要，因为硅羟基具有固有的氢键，可以给分子筛提供更多的吸附和催化位点。此外，硅羟基对于调节分子筛的性能至关重要，是插入额外活性化合物的通道。各种调节策略包括接枝离子液体和有机分子，用来创建硅羟基巢穴，直接或间接锚定活性金属，以及形成硅羟基参与吸附和催化。本文总结了硅羟基的分类方法和表征技术，并综述了调节分子筛性能的介绍方法和应用。分析了调节硅羟基需要注意的关键因素。最后，讨论了硅羟基受控分子筛性能和应用的未来发展趋势。

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引用次数: 0

A novel approach for the preparation of furandiamines utilizing biomass platform chemicals as substrates via Gabriel synthesis 通过加布里埃尔合成法以生物质平台化学品为底物制备呋喃二胺的新方法

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-14 DOI: 10.1016/j.mcat.2024.114679

Tong Sun , Shibo Yang , Yadong Liu , Xiaokai Li , Wenbo Liao , Shuxia Wei , Yong Sun

Primary diamines are significant chemical intermediates and raw materials for high-added-value chemical products, which are regarded as essential monomers in the synthesis of polyamides and polyurethanes. Primary diamines are also particularly pronounced in the automotive, aerospace, and pharmaceutical fields. Among them, 2,5-bis(aminomethyl)furan (BAF) has garnered grant attention as a highly promising renewable diamine. In this work, a new route for the reduction preparation of BAF using a platform compound 5-chloromethylfurfural (CMF) utilizing the Gabriel method was developed, which reasonably avoids the disadvantage of molecular internal polymerization that often occurs in traditional routes that converting BAF from 5-hydroxymethylfurfural (HMF) and HMF derivatives. Additionally, under mild reaction conditions, this novel route yields BAF efficiently by employing Ni/SiO₂ as the catalyst. According to the kinetic analysis the reduction process was proved to be predominant. In addition, the analysis of the mechanism showed that compared to other catalysts, Ni/SiO₂ contains more active sites and more hydrogen active components (Ni⁰), achieving an impressive yield of 82.35 % under mild conditions. This work provides a pioneering method for the preparation of BAF, which is crucial for the development of primary diamine preparation.

原生二胺是重要的化学中间体和高附加值化工产品的原材料，被视为合成聚酰胺和聚氨酯的基本单体。在汽车、航空航天和制药领域，伯胺的作用也尤为突出。其中，2,5-双（氨基甲基）呋喃（BAF）作为一种极具发展前景的可再生二元胺备受关注。在这项工作中，利用加布里埃尔法，开发出了一种利用平台化合物 5-氯甲基糠醛（CMF）还原制备 BAF 的新路线，合理地避免了由 5-羟甲基糠醛（HMF）和 HMF 衍生物转化 BAF 的传统路线中经常出现的分子内部聚合的缺点。此外，在温和的反应条件下，采用 Ni/SiO2 作为催化剂，这条新路线可以高效地生成 BAF。根据动力学分析，还原过程被证明是主要的。此外，机理分析表明，与其他催化剂相比，Ni/SiO2 含有更多的活性位点和更多的氢活性成分（Ni0），在温和条件下的产率高达 82.35%。这项研究为 BAF 的制备提供了一种开创性的方法，这对于初级二胺制备的发展至关重要。

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引用次数: 0

Unveiling the role of N species in Co/NC catalysts for photothermal CO2 hydrogenation 揭示用于二氧化碳光热加氢的 Co/NC 催化剂中 N 物种的作用

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-14 DOI: 10.1016/j.mcat.2024.114686

Pengcheng Wang , Qingqing Jiang , XingYu Li, Xuedong Wang, Juncheng Hu

Generally, researchers focus on the regulation of metal sites rather than surrounding nonmetals in photothermal CO₂ hydrogenation reaction. Herein, concerning the role of non-metallic N species, a series of Co/NC-T catalysts have been fabricated via high-temperature pyrolysis of Zeolitic Imidazolate Frameworks-67. The CO₂ conversion rate shows a consistent tendency with the ratio of graphitized-N species while the product selectivity is closely related to the coordination state of Co-N_x species. Co/NC-800 catalyst achieves high CO₂ conversion rate of 758 mmol g_cat^-1 h^-1 with CH₄ selectivity of 99.6 %. After adding extra graphitized-N species, the CO₂ conversion rate could further enhance to 80.2 % for N-Co/NC-2. The role of N species in photothermal CO₂ hydrogenation reaction has been investigated in details, providing new insights for the design of metal organic frameworks derived metal/N-doped carbon catalysts.

一般来说，研究人员关注的是光热二氧化碳加氢反应中金属位点的调控，而不是周围非金属的调控。本文针对非金属 N 物种的作用，通过高温热解沸石咪唑啉框架-67 制备了一系列 Co/NC-T 催化剂。二氧化碳转化率与石墨化 N 物种的比例呈一致趋势，而产物选择性则与 Co-Nx 物种的配位状态密切相关。Co/NC-800 催化剂的 CO2 转化率高达 758 mmol gcat-1 h-1，CH4 选择性为 99.6%。添加额外的石墨化 N 物种后，N-Co/NC-2 的 CO2 转化率进一步提高到 80.2%。详细研究了 N 物种在光热 CO2 加氢反应中的作用，为设计金属有机框架衍生的金属/N 掺杂碳催化剂提供了新的见解。

引用次数: 0

Bio-based mesoporous carbon-modified Co3O4 quantum dots as efficient electrocatalyst for freshwater, seawater and urea oxidation reaction 生物基介孔碳修饰 Co3O4 量子点作为淡水、海水和尿素氧化反应的高效电催化剂

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-13 DOI: 10.1016/j.mcat.2024.114678

Xintong Li, Min Gao, Shenglong Li, Zhichuan Yang, Xin Zhao, Yu Liu

The combination of quantum dots (QDs) with carbon materials has garnered significant attention as electrocatalysts owing to their exceptional catalytic activity and robust thermodynamic stabilities. The present study utilizes bio-based mesoporous carbon as a carbon source to synthesize QDs carbon nanostructures (Co₃O₄/BMC_-400) through hydrothermal and carbonization methods. Due to the abundance of active sites and limited availability of Co, the size of Co particles is confined to the QDs level, ranging from 2 to 3 nm. The anodic oxidation reaction of the Co₃O₄/BMC_-400 was investigated in freshwater, seawater, and urea. The prepared Co₃O₄/BMC_-400 exhibits an oxygen evolution reaction overpotential of 235 mV at 10 mA cm⁻² in 1.0 M KOH. The catalytic activity is reduced as a result of the competitive oxidation and corrosion caused by chloride ions in seawater. For the urea oxidation reaction, Co₃O₄/BMC_-400 exhibits superior catalytic performance, requiring only a potential of 1.371 V at 10 mA cm⁻², while exhibiting remarkable long-term stability for up to 30 h. More significantly, in comparison to Co₃O₄ nanosheets and nanoparticles, QDs can effectively reduce the transport pathways of alkali metal ions, thereby affording an increased number of catalytic active sites while simultaneously enhancing stability and prolonging service life. These findings may facilitate further exploration of metal-QDs/carbon materials in a wide range of electrocatalytic application.

量子点（QDs）与碳材料的结合作为电催化剂因其卓越的催化活性和强大的热力学稳定性而备受关注。本研究利用生物基介孔碳作为碳源，通过水热法和碳化法合成了量子点碳纳米结构（Co3O4/BMC-400）。由于活性位点的丰富性和 Co 的有限性，Co 颗粒的大小被限制在 2 至 3 nm 的 QDs 水平。研究了 Co3O4/BMC-400 在淡水、海水和尿素中的阳极氧化反应。制备的 Co3O4/BMC-400 在 1.0 M KOH 溶液中，10 mA cm-2 时的氧进化反应过电位为 235 mV。由于海水中氯离子造成的竞争性氧化和腐蚀，催化活性降低。更重要的是，与 Co3O4 纳米片和纳米颗粒相比，QDs 能有效减少碱金属离子的传输途径，从而增加催化活性位点的数量，同时提高稳定性并延长使用寿命。这些发现有助于进一步探索金属-QDs/碳材料在电催化领域的广泛应用。

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引用次数: 0

Insight into crystal-plane-dependent of cobalt catalysts for ethylene glycol amination 透视乙二醇胺化钴催化剂的晶体平面依赖性

IF 3.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Molecular Catalysis

Pub Date : 2024-11-13 DOI: 10.1016/j.mcat.2024.114655

Kai Li , De Zhang , Heqin Guo , Xinqi Yang , Congcong Liang , Xu Wu , Qiang Wang , Debao Li , Litao Jia

Co possesses outstanding dehydrogenation and hydrogenation activitiy and is a suitable catalyst for the amination of ethylene glycol. Nevertheless, the catalytic activity of Co's different crystal surfaces remains unclear, which hinders the further advancements in its catalytic efficiency. This research comprehensively examines the influence of Co's crystal plane effect on the amination of ethylene glycol employing both experimental and theoretical methodologies. Three single-crystal Co catalysts with mainly exposed (10−11), (0001) and (11−20) crystal planes were synthesized by a hydrothermal method and evaluated for ethylene glycol amination. The experimental results indicated that the c-Co-R catalyst with exposed Co (11–20) crystal facets exhibits optimal performance, with a 55.4 % ethylene glycol conversion and a 43.7 % primary amines (ethylenediamine and ethanolamine) selectivity. Combined with density-functional theory calculations and experimental characterization, the results showed that the Co (11−20) surface exhibited robust C-H bond dissociation and strong adsorption of ethylene glycol, which markedly improved the dehydrogenation efficiency of ethylene glycol and improved ethylene glycol conversion. Furthermore, the weak adsorption capacity of NH₃ further promoted the selectivity of the target products.

Co 具有出色的脱氢和加氢活性，是乙二醇胺化反应的合适催化剂。然而，Co 不同晶面的催化活性尚不明确，这阻碍了其催化效率的进一步提高。本研究采用实验和理论方法，全面考察了 Co 的晶面效应对乙二醇胺化反应的影响。通过水热法合成了三种单晶 Co 催化剂，其晶面主要暴露在 (10-11)、(0001) 和 (11-20) 面上，并对其进行了乙二醇胺化评估。实验结果表明，具有暴露 Co (11-20) 晶面的 c-Co-R 催化剂具有最佳性能，乙二醇转化率为 55.4%，伯胺（乙二胺和乙醇胺）选择性为 43.7%。结合密度泛函理论计算和实验表征，结果表明，Co（11-20）表面表现出强劲的 C-H 键解离和对乙二醇的强吸附，从而显著提高了乙二醇的脱氢效率，改善了乙二醇的转化率。此外，NH3 的弱吸附能力进一步提高了目标产物的选择性。

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