Yannick Ureel, Konstantinos Alexopoulos, Kevin M Van Geem, Maarten K Sabbe
Developing improved zeolites is essential in novel sustainable processes such as the catalytic pyrolysis of plastic waste. This study used density functional theory to investigate how alkyl chain length, unsaturated bonds, and branching affect β-scission kinetics in four zeolite frameworks, a key reaction in hydrocarbon cracking. The activation enthalpy was evaluated for a wide variety of 23 hydrocarbons, with 6 to 12 carbon atoms, in FAU, MFI, MOR, and TON. The consideration of both branched and linear olefin and diolefin reactants for the β-scission indicates how the reactant structure influences the intrinsic cracking kinetics, which is especially relevant for the catalytic cracking of plastic waste feedstocks. Intrinsic chemical effects, such as resonance stabilization, the inductive effect, and pore stabilization were found to provide an essential contribution to the activation enthalpy. Additionally, a predictive group additive model incorporating a novel so-called "pore confinement descriptor" was developed for fast prediction of the β-scission activation barrier of a wide range of molecules in the four zeolites. The obtained model can serve as an input for detailed kinetic models in zeolite-catalyzed cracking reactions. The acquired fundamental insights in the cracking of hydrocarbons, relevant for renewable feedstocks, correspond well with experimental observations and will facilitate an improved rational zeolite design.
{"title":"Predicting the effect of framework and hydrocarbon structure on the zeolite-catalyzed beta-scission.","authors":"Yannick Ureel, Konstantinos Alexopoulos, Kevin M Van Geem, Maarten K Sabbe","doi":"10.1039/d4cy00973h","DOIUrl":"https://doi.org/10.1039/d4cy00973h","url":null,"abstract":"<p><p>Developing improved zeolites is essential in novel sustainable processes such as the catalytic pyrolysis of plastic waste. This study used density functional theory to investigate how alkyl chain length, unsaturated bonds, and branching affect β-scission kinetics in four zeolite frameworks, a key reaction in hydrocarbon cracking. The activation enthalpy was evaluated for a wide variety of 23 hydrocarbons, with 6 to 12 carbon atoms, in FAU, MFI, MOR, and TON. The consideration of both branched and linear olefin and diolefin reactants for the β-scission indicates how the reactant structure influences the intrinsic cracking kinetics, which is especially relevant for the catalytic cracking of plastic waste feedstocks. Intrinsic chemical effects, such as resonance stabilization, the inductive effect, and pore stabilization were found to provide an essential contribution to the activation enthalpy. Additionally, a predictive group additive model incorporating a novel so-called \"pore confinement descriptor\" was developed for fast prediction of the β-scission activation barrier of a wide range of molecules in the four zeolites. The obtained model can serve as an input for detailed kinetic models in zeolite-catalyzed cracking reactions. The acquired fundamental insights in the cracking of hydrocarbons, relevant for renewable feedstocks, correspond well with experimental observations and will facilitate an improved rational zeolite design.</p>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11474451/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142453596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing a highly efficient visible-light-driven TiO2-based photocatalyst for the degradation of tetracycline remains challenging due to the high photogenerated electron/hole recombination rate and narrow visible light response range of TiO2. To address these problems, novel heterojunctions are fabricated by coupling TiO2 nanosheets with Mn0.5Cd0.5S nanoparticles as visible-light photocatalysts. The as-synthesized photocatalysts exhibit high photogenerated electron/hole separation efficiency and enhanced visible-light absorption due to the well-matched energy levels, leading to the highly efficient degradation of tetracycline under visible light irradiation and excellent recyclability. The degradation efficiency of the optimum MCS/TiO2-II photocatalyst could reach 90% within 120 min, which was about 2.5 times and 6.9 times higher than those of MCS and TiO2, respectively. Furthermore, the degradation mechanism of tetracycline was revealed in depth based on the trapping experiments, XPS, photoelectrochemical characterizations, and DFT calculations. Therefore, this work provides an effective approach to explore excellent photocatalysts to realize the highly efficient removal of refractory tetracycline under visible light.
{"title":"Facile in situ construction strategy to deposit Mn0.5Cd0.5S nanoparticles on TiO2 nanosheets for highly efficient visible light photocatalytic degradation of tetracycline","authors":"","doi":"10.1039/d4cy00868e","DOIUrl":"10.1039/d4cy00868e","url":null,"abstract":"<div><div>Developing a highly efficient visible-light-driven TiO<sub>2</sub>-based photocatalyst for the degradation of tetracycline remains challenging due to the high photogenerated electron/hole recombination rate and narrow visible light response range of TiO<sub>2</sub>. To address these problems, novel heterojunctions are fabricated by coupling TiO<sub>2</sub> nanosheets with Mn<sub>0.5</sub>Cd<sub>0.5</sub>S nanoparticles as visible-light photocatalysts. The as-synthesized photocatalysts exhibit high photogenerated electron/hole separation efficiency and enhanced visible-light absorption due to the well-matched energy levels, leading to the highly efficient degradation of tetracycline under visible light irradiation and excellent recyclability. The degradation efficiency of the optimum MCS/TiO<sub>2</sub>-II photocatalyst could reach 90% within 120 min, which was about 2.5 times and 6.9 times higher than those of MCS and TiO<sub>2</sub>, respectively. Furthermore, the degradation mechanism of tetracycline was revealed in depth based on the trapping experiments, XPS, photoelectrochemical characterizations, and DFT calculations. Therefore, this work provides an effective approach to explore excellent photocatalysts to realize the highly efficient removal of refractory tetracycline under visible light.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stereoselective ring opening polymerization (ROP) of racemic lactide (rac-LA) is a challenging goal because a rationale connecting the catalyst structure and polymer microstructure (as has been established for α-olefin polymerization) is still missing. In this work, we reveal the origin of the stereoselective preference for d and l-lactide with two enantiopure salen–Al complexes, which have so far been claimed as the most efficient in enantiomorphic site control, using Density Functional Theory calculations. We introduce active site reorganization and monomer/chain switching throughout the reaction pathway, unconventional aspects necessitating careful consideration when confronting the intricacies associated with chiral catalyst recognition. We show how the catalytic pocket easily rearranges in the reaction path establishing a novel concept of the ligand coordination controlled by monomer binding. The resulting final picture of PLA stereoselectivity is much more complex than that of α-olefin polymerization catalysis, and a “complete” prediction by brute-force is (currently) hard, but the principles evolving should – even in their incomplete form – be useful in the design of new selective catalysts.
外消旋内酰胺（rac-LA）的立体选择性开环聚合（ROP）是一个具有挑战性的目标，因为目前还没有将催化剂结构与聚合物微观结构联系起来的理论依据（就像α-烯烃聚合一样）。在这项工作中，我们利用密度泛函理论计算揭示了两种不对映纯的沙仑-铝配合物对 D 和 L-内酰胺立体选择性偏好的起源，迄今为止，这两种配合物一直被认为是对映位点控制最有效的催化剂。我们在整个反应路径中引入了活性位点重组和单体/链切换，在面对与手性催化剂识别相关的错综复杂问题时，有必要仔细考虑这些非常规方面。我们展示了催化袋如何在反应路径中轻松地重新排列，从而建立了一个由单体结合控制配体配位的新概念。由此得出的聚乳酸立体选择性最终图景要比α-烯烃聚合催化图景复杂得多，（目前）很难通过蛮力做出 "完整 "的预测，但即使是在不完整的形式下，演变出的原理也应有助于设计新的选择性催化剂。
{"title":"Ligand coordination controlled by monomer binding: a hint from DFT for stereoselective lactide polymerization†","authors":"","doi":"10.1039/d4cy00937a","DOIUrl":"10.1039/d4cy00937a","url":null,"abstract":"<div><div>Stereoselective ring opening polymerization (ROP) of racemic lactide (<em>rac</em>-LA) is a challenging goal because a rationale connecting the catalyst structure and polymer microstructure (as has been established for α-olefin polymerization) is still missing. In this work, we reveal the origin of the stereoselective preference for <span>d</span> and <span>l</span>-lactide with two enantiopure salen–Al complexes, which have so far been claimed as the most efficient in enantiomorphic site control, using Density Functional Theory calculations. We introduce active site reorganization and monomer/chain switching throughout the reaction pathway, unconventional aspects necessitating careful consideration when confronting the intricacies associated with chiral catalyst recognition. We show how the catalytic pocket easily rearranges in the reaction path establishing a novel concept of the ligand coordination controlled by monomer binding. The resulting final picture of PLA stereoselectivity is much more complex than that of α-olefin polymerization catalysis, and a “complete” prediction by brute-force is (currently) hard, but the principles evolving should – even in their incomplete form – be useful in the design of new selective catalysts.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/cy/d4cy00937a?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
CuO/am-ZrO2 promotes the homocoupling of boronic acids under air and mild conditions without requiring external additives owing to the presence of easily reducible [CuO4] clusters. This catalyst suppresses the adsorption of MeOH solvent, thereby reducing MeOH-related side reactions and enhancing the selectivity and efficiency of the desired reaction.
{"title":"Aerobic homocoupling of arylboronic acids using Cu-doped amorphous zirconia: impact of catalyst amorphousness on reaction efficiency†","authors":"","doi":"10.1039/d4cy00694a","DOIUrl":"10.1039/d4cy00694a","url":null,"abstract":"<div><div>CuO/am-ZrO<sub>2</sub> promotes the homocoupling of boronic acids under air and mild conditions without requiring external additives owing to the presence of easily reducible [CuO<sub>4</sub>] clusters. This catalyst suppresses the adsorption of MeOH solvent, thereby reducing MeOH-related side reactions and enhancing the selectivity and efficiency of the desired reaction.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coinage (Au, Ag, Cu) metal-catalyzed (3 + 2) annulation of α-aminoketones and electron-deficient alkynes provides a modular one-step route to a variety of 3-EWG-substituted pyrroles. Apart from gold(i) complexes, which “open any door” and catalyze the annulation regardless of the identity of the alkyne EWGs [–SO2R, –CO2R, –PO(OR)2], the other cheaper coinage metal (first of all Cu, but also Ag) species function as alternative catalysts for the selective activation of alkynylsulfones and their conversion to 3-sulfonylpyrroles. The developed catalytic annulation operates under relatively mild conditions (5 mol% of a coinage metal catalyst, DCE, 80 °C) and provides a high functional group tolerance (36 examples; yields up to 99%). The synthetic utility of the obtained products was illustrated by practical post-modification of either the pyrrole backbone, or the peripheral substituents.
{"title":"Coinage (Au, Ag, Cu) metal-catalyzed (3 + 2) annulation of α-aminoketones and electron-deficient alkynes as a route to 3-EWG-substituted pyrroles†","authors":"","doi":"10.1039/d4cy00660g","DOIUrl":"10.1039/d4cy00660g","url":null,"abstract":"<div><div>Coinage (Au, Ag, Cu) metal-catalyzed (3 + 2) annulation of α-aminoketones and electron-deficient alkynes provides a modular one-step route to a variety of 3-EWG-substituted pyrroles. Apart from gold(<span>i</span>) complexes, which “open any door” and catalyze the annulation regardless of the identity of the alkyne EWGs [–SO<sub>2</sub>R, –CO<sub>2</sub>R, –PO(OR)<sub>2</sub>], the other cheaper coinage metal (first of all Cu, but also Ag) species function as alternative catalysts for the selective activation of alkynylsulfones and their conversion to 3-sulfonylpyrroles. The developed catalytic annulation operates under relatively mild conditions (5 mol% of a coinage metal catalyst, DCE, 80 °C) and provides a high functional group tolerance (36 examples; yields up to 99%). The synthetic utility of the obtained products was illustrated by practical post-modification of either the pyrrole backbone, or the peripheral substituents.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The local coordination environment of single atom catalysts (SACs) often determines their catalytic performance. To understand these metal–support interactions, we prepared Pt SACs on cerium dioxide (CeO2) cubes, octahedra and rods, with well-structured exposed crystal facets. The CeO2 crystals were characterized by SEM, TEM, pXRD, and N2 sorption, confirming the shape-selective synthesis, identical bulk structure, and variations in specific surface area, respectively. EPR, XPS, TEM and XANES measurements showed differences in the oxygen vacancy density following the trend rods > octahedra > cubes. AC-HAADF-STEM, XPS and CO-DRIFTS measurements confirmed the presence of only single Pt2+ sites, with different surface platinum surface concentrations. We then compared the performance of the three catalysts in ammonia borane hydrolysis. Precise monitoring of reaction kinetics between 30–80 °C gave Arrhenius plots with hundreds of data points. All plots showed a clear inflection point, the temperature of which (rods > octahedra > cubes) correlates to the energy barrier of ammonia borane diffusion to the Pt sites. These activity differences reflect variations in the – facet dependent – degree of stabilization of intermediates by surface oxygen lone pairs and surface–metal binding strength. Our results show how choosing the right macroscopic support shape can give control over single atom catalysed reactions on the microscopic scale.
{"title":"Tuning catalytic performance of platinum single atoms by choosing the shape of cerium dioxide supports†","authors":"","doi":"10.1039/d4cy00484a","DOIUrl":"10.1039/d4cy00484a","url":null,"abstract":"<div><div>The local coordination environment of single atom catalysts (SACs) often determines their catalytic performance. To understand these metal–support interactions, we prepared Pt SACs on cerium dioxide (CeO<sub>2</sub>) cubes, octahedra and rods, with well-structured exposed crystal facets. The CeO<sub>2</sub> crystals were characterized by SEM, TEM, pXRD, and N<sub>2</sub> sorption, confirming the shape-selective synthesis, identical bulk structure, and variations in specific surface area, respectively. EPR, XPS, TEM and XANES measurements showed differences in the oxygen vacancy density following the trend rods > octahedra > cubes. AC-HAADF-STEM, XPS and CO-DRIFTS measurements confirmed the presence of only single Pt<sup>2+</sup> sites, with different surface platinum surface concentrations. We then compared the performance of the three catalysts in ammonia borane hydrolysis. Precise monitoring of reaction kinetics between 30–80 °C gave Arrhenius plots with hundreds of data points. All plots showed a clear inflection point, the temperature of which (rods > octahedra > cubes) correlates to the energy barrier of ammonia borane diffusion to the Pt sites. These activity differences reflect variations in the – facet dependent – degree of stabilization of intermediates by surface oxygen lone pairs and surface–metal binding strength. Our results show how choosing the right macroscopic support shape can give control over single atom catalysed reactions on the microscopic scale.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11322700/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141998941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrochemical hydrodeoxygenation (EC-HDO) is a promising method for upgrading biomass derived oxygenates into biofuels at near ambient conditions without the need for external hydrogen (H2). Although the EC-HDO approach has many advantages over conventional thermochemical hydrodeoxygenation (HDO) methods, the selective production of fully deoxygenated hydrocarbons remains a key challenge. In this study we explore the EC-HDO of phenol as a bio-oil-derived model compound using carbon supported metal electrocatalysts in a custom-made divided electrochemical batch cell. We demonstrated EC-HDO of phenol to cyclohexane and investigated the effect of multiple variables, including catalyst type, and cathodic potential to determine their influence on reaction rate, selectivity, and faradaic efficiency (FE). The results obtained show that lab-synthesized, bi-metallic PtRu–C catalyst results in the highest specific EC-HDO rate of 5.05 molcyclohexane h−1 gmetal−1 in comparison to 4.65 molcyclohexane h−1 gmetal−1 and 0.35 molcyclohexane h−1 gmetal−1, measured using mono-metallic Pt–C and Ru–C catalysts, respectively. In addition, the labPtRu–C electrocatalyst achieved >30% selectivity towards cyclohexane while the monometallic Pt and Ru only achieved 25 and 11%, respectively. Operando Raman spectroscopy demonstrated strong evidence for ketone reaction intermediates.
{"title":"Effect of Pt and Ru-based catalysts on the electrochemical hydrodeoxygenation of phenol to cyclohexane†","authors":"","doi":"10.1039/d4cy00634h","DOIUrl":"10.1039/d4cy00634h","url":null,"abstract":"<div><div>Electrochemical hydrodeoxygenation (EC-HDO) is a promising method for upgrading biomass derived oxygenates into biofuels at near ambient conditions without the need for external hydrogen (H<sub>2</sub>). Although the EC-HDO approach has many advantages over conventional thermochemical hydrodeoxygenation (HDO) methods, the selective production of fully deoxygenated hydrocarbons remains a key challenge. In this study we explore the EC-HDO of phenol as a bio-oil-derived model compound using carbon supported metal electrocatalysts in a custom-made divided electrochemical batch cell. We demonstrated EC-HDO of phenol to cyclohexane and investigated the effect of multiple variables, including catalyst type, and cathodic potential to determine their influence on reaction rate, selectivity, and faradaic efficiency (FE). The results obtained show that lab-synthesized, bi-metallic PtRu–C catalyst results in the highest specific EC-HDO rate of 5.05 mol<sub>cyclohexane</sub> h<sup>−1</sup> g<sub>metal</sub><sup>−1</sup> in comparison to 4.65 mol<sub>cyclohexane</sub> h<sup>−1</sup> g<sub>metal</sub><sup>−1</sup> and 0.35 mol<sub>cyclohexane</sub> h<sup>−1</sup> g<sub>metal</sub><sup>−1</sup>, measured using mono-metallic Pt–C and Ru–C catalysts, respectively. In addition, the labPtRu–C electrocatalyst achieved >30% selectivity towards cyclohexane while the monometallic Pt and Ru only achieved 25 and 11%, respectively. <em>Operando</em> Raman spectroscopy demonstrated strong evidence for ketone reaction intermediates.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/cy/d4cy00634h?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141936834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The chemical recycling of used polyethylene terephthalate (PET) bottles, a widely used plastic in the modern world, to obtain valuable monomers offers a promising solution to address post-consumer plastic-related environmental concerns. In this study, we have developed an efficient heterogeneous catalytic approach using a shape-engineered manganese oxide (MnOx) nanocatalyst with a well-defined rod morphology to facilitate the glycolysis of PET with biomass-derived ethylene glycol to produce a high-quality bis(2-hydroxyethyl) terephthalate (BHET) valuable monomer under mild conditions. The nanorod morphology of the MnOx material, specifically the MnOx calcined at 500 °C (MnOx-500), exhibited remarkable catalytic efficiency in converting used PET bottles into BHET. At a temperature of 180 °C for 3 h, the MnOx-500 nanocatalyst achieved a complete conversion of PET with a 86% isolated yield of BHET, surpassing the performance of various metal oxides, such as CeO2, TiO2, and Nb2O5. Qualitative analysis of the isolated BHET monomer crystals was conducted using NMR, FT-IR, HR-MS, and powder XRD, along with assessments of thermal stability through TGA and DSC studies. Furthermore, the study demonstrated the catalyst's stability and reusability, suggesting the practical application potential of this methodology. The structure–activity correlation, revealed through comprehensive characterization of the nanostructured MnOx materials, highlighted the crucial role of the oxygen vacancy defects and the acidic properties in the MnOx-500 nanocatalyst for efficient PET glycolysis to obtain the desired BHET monomer.
废旧聚对苯二甲酸乙二醇酯（PET）瓶是现代社会广泛使用的一种塑料，对其进行化学回收利用以获得有价值的单体，为解决消费后塑料相关的环境问题提供了一种前景广阔的解决方案。在这项研究中，我们开发了一种高效的异相催化方法，利用具有明确棒状形态的形状工程化氧化锰（MnOx）纳米催化剂，在温和的条件下促进 PET 与生物质衍生乙二醇的乙二醇化，从而生产出高质量的对苯二甲酸二（2-羟乙基）酯（BHET）有价单体。氧化锰材料的纳米棒形态，特别是在 500 °C 煅烧的氧化锰（MnOx-500），在将废旧 PET 瓶转化为 BHET 的过程中表现出显著的催化效率。在 180 °C 的温度下煅烧 3 小时后，MnOx-500 纳米催化剂实现了 PET 的完全转化，分离出的 BHET 产率达到 86%，超过了 CeO2、TiO2 和 Nb2O5 等各种金属氧化物的性能。利用 NMR、FT-IR、HR-MS 和粉末 XRD 对分离出的 BHET 单体晶体进行了定性分析，并通过 TGA 和 DSC 研究对热稳定性进行了评估。此外，该研究还证明了催化剂的稳定性和可重复使用性，表明这种方法具有实际应用潜力。通过对纳米结构 MnOx 材料进行综合表征，发现了结构与活性之间的相关性，突出了 MnOx-500 纳米催化剂中的氧空位缺陷和酸性特性在高效 PET 糖解以获得所需的 BHET 单体中的关键作用。
{"title":"Efficient glycolysis of used PET bottles into a high-quality valuable monomer using a shape-engineered MnOx nanocatalyst†","authors":"","doi":"10.1039/d4cy00823e","DOIUrl":"10.1039/d4cy00823e","url":null,"abstract":"<div><div>The chemical recycling of used polyethylene terephthalate (PET) bottles, a widely used plastic in the modern world, to obtain valuable monomers offers a promising solution to address post-consumer plastic-related environmental concerns. In this study, we have developed an efficient heterogeneous catalytic approach using a shape-engineered manganese oxide (MnO<sub>x</sub>) nanocatalyst with a well-defined rod morphology to facilitate the glycolysis of PET with biomass-derived ethylene glycol to produce a high-quality bis(2-hydroxyethyl) terephthalate (BHET) valuable monomer under mild conditions. The nanorod morphology of the MnO<sub>x</sub> material, specifically the MnO<sub>x</sub> calcined at 500 °C (MnO<sub>x</sub>-500), exhibited remarkable catalytic efficiency in converting used PET bottles into BHET. At a temperature of 180 °C for 3 h, the MnO<sub>x</sub>-500 nanocatalyst achieved a complete conversion of PET with a 86% isolated yield of BHET, surpassing the performance of various metal oxides, such as CeO<sub>2</sub>, TiO<sub>2</sub>, and Nb<sub>2</sub>O<sub>5</sub>. Qualitative analysis of the isolated BHET monomer crystals was conducted using NMR, FT-IR, HR-MS, and powder XRD, along with assessments of thermal stability through TGA and DSC studies. Furthermore, the study demonstrated the catalyst's stability and reusability, suggesting the practical application potential of this methodology. The structure–activity correlation, revealed through comprehensive characterization of the nanostructured MnO<sub>x</sub> materials, highlighted the crucial role of the oxygen vacancy defects and the acidic properties in the MnO<sub>x</sub>-500 nanocatalyst for efficient PET glycolysis to obtain the desired BHET monomer.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transfer hydrogenative reductive amination of 5-(hydroxymethy)furfural (HMF) has been accomplished, catalysed by a cyclometalated iridium catalyst with formic acid as a hydrogen source. The catalytic system afforded a TON of 9600 and TOF of 14 400 h−1, and the reaction can be successfully scaled up to a 10 gram scale at a substrate-to-catalyst ratio of 10 000. A wide range of amines could be coupled with HMF to afford furan derived products, including modified drug molecules, key intermediates for drug synthesis and potential monomers for polymer synthesis.
{"title":"Efficient reductive amination of 5-hydroxymethylfurfural by iridium-catalysed transfer hydrogenation†","authors":"","doi":"10.1039/d4cy00812j","DOIUrl":"10.1039/d4cy00812j","url":null,"abstract":"<div><div>Transfer hydrogenative reductive amination of 5-(hydroxymethy)furfural (HMF) has been accomplished, catalysed by a cyclometalated iridium catalyst with formic acid as a hydrogen source. The catalytic system afforded a TON of 9600 and TOF of 14 400 h<sup>−1</sup>, and the reaction can be successfully scaled up to a 10 gram scale at a substrate-to-catalyst ratio of 10 000. A wide range of amines could be coupled with HMF to afford furan derived products, including modified drug molecules, key intermediates for drug synthesis and potential monomers for polymer synthesis.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dimethyl ether to gasoline (DTG) process is an important way to obtain transportation fuels from non-petroleum routes due to the ever-decreasing fossil energy under “dual-carbon” background, and the development of catalyst with long lifetime remains an important challenge. Herein, the hierarchical nanocrystalline H[Fe,Al]ZSM-5 zeolites composed of loosely aggregated nanocrystals were prepared by adding a mesoporous template and prolonging the aging time, and their physicochemical properties and reactivity over the DTG reaction were investigated and compared with that of conventional H[Fe,Al]ZSM-5. The size of individual nanocrystals became smaller and more uniform, and the nanocrystals were loosely aggregated with abundant intercrystal mesopores, resulting in the significant enhancement of catalyst lifetime. Furthermore, the acid intensity of hierarchical nanocrystalline zeolites weakened, and the strong acid amount was reduced. DTG reaction results illustrated that the hierarchical nanocrystalline zeolite of Mes-ZSM-5 using a mesoporous template exhibited the longest lifetime (182 h) with 100% DME conversion, and gasoline yield remained more than 70%. Moreover, the C5+ selectivity was up to 76.6%; meanwhile, the contents of aromatics, benzene and durene were as low as 40%, 0.6% and 1.7%, respectively. The obtained gasoline product had a higher RON (research octane numbers).
{"title":"Facile synthesis of hierarchical nanocrystalline H[Fe,Al]ZSM-5 with boosted lifetime for DTG reactions","authors":"","doi":"10.1039/d4cy00838c","DOIUrl":"10.1039/d4cy00838c","url":null,"abstract":"<div><div>Dimethyl ether to gasoline (DTG) process is an important way to obtain transportation fuels from non-petroleum routes due to the ever-decreasing fossil energy under “dual-carbon” background, and the development of catalyst with long lifetime remains an important challenge. Herein, the hierarchical nanocrystalline H[Fe,Al]ZSM-5 zeolites composed of loosely aggregated nanocrystals were prepared by adding a mesoporous template and prolonging the aging time, and their physicochemical properties and reactivity over the DTG reaction were investigated and compared with that of conventional H[Fe,Al]ZSM-5. The size of individual nanocrystals became smaller and more uniform, and the nanocrystals were loosely aggregated with abundant intercrystal mesopores, resulting in the significant enhancement of catalyst lifetime. Furthermore, the acid intensity of hierarchical nanocrystalline zeolites weakened, and the strong acid amount was reduced. DTG reaction results illustrated that the hierarchical nanocrystalline zeolite of Mes-ZSM-5 using a mesoporous template exhibited the longest lifetime (182 h) with 100% DME conversion, and gasoline yield remained more than 70%. Moreover, the C<sub>5</sub><sup>+</sup> selectivity was up to 76.6%; meanwhile, the contents of aromatics, benzene and durene were as low as 40%, 0.6% and 1.7%, respectively. The obtained gasoline product had a higher RON (research octane numbers).</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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