Pub Date : 2025-09-03DOI: 10.1016/j.cattod.2025.115547
Yeonwoo Do , Seohee Jang , Seokho Lee , Yiyun Yang , Yunjeong Jang , Hyun-Suk Kim , Kwun-Bum Chung , Kyung-Wan Nam , Yoon Kee Kim , Kihyun Shin
This research focused on maximizing the catalytic activity in nanocubes (NCs) with (100) facets. The primary goal was to reduce the adsorption energy of the adsorbate, thereby enhancing the activity of the fuel cell catalyst and approaching the optimal point on the volcano plot. We induced strain by introducing core elements such as Ru, Rh, Ir, Au, Ag, Ni, Pt, Cu, and their intermetallic compounds. The adsorption energy for intermediates (such as O, OH, and OOH) was calculated by exploring various adsorption sites. Studies of strain and charge analysis have been conducted, providing deeper insight into interactions at the atomic level. Strain analysis revealed how the different core elements affect the lattice parameters and consequently the adsorption energy of the intermediates. Charge analysis highlighted the redistribution of electron density upon adsorption, providing a clearer picture of the relationship between strain, electronic structure, and catalytic activity. The study illuminated the prospect of advancing fuel cell technology through a comprehensive understanding of the interplay between the surface reconstruction and strain on the (100) surface. Such understanding enabled effective manipulation of catalytic adsorption energy, offering promising strategies for further enhancing fuel cell catalyst activity.
{"title":"Strain-driven adsorption site modification on Pd-based nano cube for fuel cell application","authors":"Yeonwoo Do , Seohee Jang , Seokho Lee , Yiyun Yang , Yunjeong Jang , Hyun-Suk Kim , Kwun-Bum Chung , Kyung-Wan Nam , Yoon Kee Kim , Kihyun Shin","doi":"10.1016/j.cattod.2025.115547","DOIUrl":"10.1016/j.cattod.2025.115547","url":null,"abstract":"<div><div>This research focused on maximizing the catalytic activity in nanocubes (NCs) with (100) facets. The primary goal was to reduce the adsorption energy of the adsorbate, thereby enhancing the activity of the fuel cell catalyst and approaching the optimal point on the volcano plot. We induced strain by introducing core elements such as Ru, Rh, Ir, Au, Ag, Ni, Pt, Cu, and their intermetallic compounds. The adsorption energy for intermediates (such as O, OH, and OOH) was calculated by exploring various adsorption sites. Studies of strain and charge analysis have been conducted, providing deeper insight into interactions at the atomic level. Strain analysis revealed how the different core elements affect the lattice parameters and consequently the adsorption energy of the intermediates. Charge analysis highlighted the redistribution of electron density upon adsorption, providing a clearer picture of the relationship between strain, electronic structure, and catalytic activity. The study illuminated the prospect of advancing fuel cell technology through a comprehensive understanding of the interplay between the surface reconstruction and strain on the (100) surface. Such understanding enabled effective manipulation of catalytic adsorption energy, offering promising strategies for further enhancing fuel cell catalyst activity.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115547"},"PeriodicalIF":5.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-03DOI: 10.1016/j.cattod.2025.115529
Michiko Kitagawa , Hiromi Matsuhashi
Temperature-programmed desorption using propane, propylene, isobutane (2-methylbutane), and isobutene (2-methylpropene) was applied to study the base strength of MgO and related solid base catalysts. Among the used probe molecules, propylene showed a strong interaction with base sites over solid bases. The desorption peak of propylene from base catalysts having reduced activity was moved to the lower temperature. The activation energies of propylene desorption calculated by applying Amenomiya's equation were 54, 44, 36, and 57 kJ mol–1 for CaO, MgO, hydrotalcite dried at 373 K, and MgO–Al2O3 prepared by thermal decomposition of hydrotalcite, respectively. The order of activation energy of propylene desorption coincided with that of diacetone alcohol decomposition to acetone, except MgO–Al2O3. It was clarified that propylene was superior as the probe molecule for base strength analysis.
{"title":"Measurement of the base strength of MgO and related solid base catalysts by temperature-programmed desorption using propylene as a probe molecule","authors":"Michiko Kitagawa , Hiromi Matsuhashi","doi":"10.1016/j.cattod.2025.115529","DOIUrl":"10.1016/j.cattod.2025.115529","url":null,"abstract":"<div><div>Temperature-programmed desorption using propane, propylene, isobutane (2-methylbutane), and isobutene (2-methylpropene) was applied to study the base strength of MgO and related solid base catalysts. Among the used probe molecules, propylene showed a strong interaction with base sites over solid bases. The desorption peak of propylene from base catalysts having reduced activity was moved to the lower temperature. The activation energies of propylene desorption calculated by applying Amenomiya's equation were 54, 44, 36, and 57 kJ mol<sup>–1</sup> for CaO, MgO, hydrotalcite dried at 373 K, and MgO–Al<sub>2</sub>O<sub>3</sub> prepared by thermal decomposition of hydrotalcite, respectively. The order of activation energy of propylene desorption coincided with that of diacetone alcohol decomposition to acetone, except MgO–Al<sub>2</sub>O<sub>3</sub>. It was clarified that propylene was superior as the probe molecule for base strength analysis.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115529"},"PeriodicalIF":5.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-02DOI: 10.1016/j.cattod.2025.115544
Yan Fang , Chengcheng Cai , Hiromi Yamashita , Xufang Qian , Yixin Zhao
Electrocatalytic CO2 reduction reaction (CRR) to produce value-added chemicals offers a sustainable strategy to address energy crisis and climate change. However, the conventional CRR is always coupled with the anodic oxygen evolution reaction (OER), suffering from large overpotential, and high energy consumption. To overcome this, we proposed an alternative system by pairing CRR with the electrocatalytic oxidation of ethylene glycol (EGOR), a product derived from the depolymerization of polyethylene terephthalate (PET) plastic waste. This novel coupled system enabled the simultaneous production of formate on both electrodes, achieving the dual utilization of plastic waste and CO2. In this study, we developed a commercially viable system combining a robust NiOOH electrocatalyst synthesized through a facile electrodeposition for EGOR with a low-cost Bi2O3 electrocatalyst for CRR. The NiOOH electrocatalyst achieved Faradaic efficiencies over 88 % for EG oxidation into formate within a broad potential window (1.4–1.8 VRHE), while Bi2O3 delivered Faradaic efficiencies more than 90 % for CO2-to-formate conversion within −0.8 to −1.2 VRHE. When integrated in a two-electrode configuration, the EGOR/CRR system produced formate at both electrodes with Faradaic efficiencies above 85 % across a wide cell voltage (2.0–2.6 V), requiring a ∼300 mV lower cell potential compared to the OER/CRR system. This coupled system reached commercial-level current densities above 200 mA cm−2 or 400 mA cm−2 at 3.0 V when implemented in the flow cell or the MEA cell, respectively. These results demonstrated the potential to use waste-derived reactants and commercially accessible eletrocatalytsts to realize energy-efficient and scalable conversion into formate.
电催化二氧化碳还原反应（CRR）生产增值化学品为解决能源危机和气候变化提供了一种可持续的战略。然而，传统的CRR总是与阳极析氧反应（OER）耦合，存在过电位大、能耗高的问题。为了克服这一问题，我们提出了一种替代系统，将CRR与乙二醇（EGOR）的电催化氧化配对，乙二醇是聚对苯二甲酸乙二醇酯（PET）塑料废物解聚的产物。这种新型的耦合系统能够在两个电极上同时生产甲酸盐，实现塑料废物和二氧化碳的双重利用。在这项研究中，我们开发了一种商业上可行的系统，结合了通过简单电沉积合成的用于EGOR的强大NiOOH电催化剂和用于CRR的低成本Bi2O3电催化剂。NiOOH电催化剂在宽电位窗口（1.4-1.8 VRHE）内将EG氧化为甲酸的法拉第效率超过88 %，而Bi2O3在−0.8至−1.2 VRHE范围内将co2转化为甲酸的法拉第效率超过90 %。当集成在双电极配置中时，EGOR/CRR系统在两个电极上产生甲酸，在宽电池电压（2.0-2.6 V）下，法拉第效率高于85% %，与OER/CRR系统相比，电池电位需要降低~ 300 mV。当在流动电池或MEA电池中实现时，该耦合系统在3.0 V下分别达到200 mA cm - 2或400 mA cm - 2以上的商业级电流密度。这些结果证明了利用废物衍生反应物和商业上可获得的电催化剂实现高效和可扩展的转化为甲酸盐的潜力。
{"title":"Efficient and cost-effective electrocatalysts for coproduction of formate through electrocatalytic oxidation of PET-derived ethylene glycol coupled with CO2 reduction","authors":"Yan Fang , Chengcheng Cai , Hiromi Yamashita , Xufang Qian , Yixin Zhao","doi":"10.1016/j.cattod.2025.115544","DOIUrl":"10.1016/j.cattod.2025.115544","url":null,"abstract":"<div><div>Electrocatalytic CO<sub>2</sub> reduction reaction (CRR) to produce value-added chemicals offers a sustainable strategy to address energy crisis and climate change. However, the conventional CRR is always coupled with the anodic oxygen evolution reaction (OER), suffering from large overpotential, and high energy consumption. To overcome this, we proposed an alternative system by pairing CRR with the electrocatalytic oxidation of ethylene glycol (EGOR), a product derived from the depolymerization of polyethylene terephthalate (PET) plastic waste. This novel coupled system enabled the simultaneous production of formate on both electrodes, achieving the dual utilization of plastic waste and CO<sub>2</sub>. In this study, we developed a commercially viable system combining a robust NiOOH electrocatalyst synthesized through a facile electrodeposition for EGOR with a low-cost Bi<sub>2</sub>O<sub>3</sub> electrocatalyst for CRR. The NiOOH electrocatalyst achieved Faradaic efficiencies over 88 % for EG oxidation into formate within a broad potential window (1.4–1.8 V<sub>RHE</sub>), while Bi<sub>2</sub>O<sub>3</sub> delivered Faradaic efficiencies more than 90 % for CO<sub>2</sub>-to-formate conversion within −0.8 to −1.2 V<sub>RHE</sub>. When integrated in a two-electrode configuration, the EGOR/CRR system produced formate at both electrodes with Faradaic efficiencies above 85 % across a wide cell voltage (2.0–2.6 V), requiring a ∼300 mV lower cell potential compared to the OER/CRR system. This coupled system reached commercial-level current densities above 200 mA cm<sup>−2</sup> or 400 mA cm<sup>−2</sup> at 3.0 V when implemented in the flow cell or the MEA cell, respectively. These results demonstrated the potential to use waste-derived reactants and commercially accessible eletrocatalytsts to realize energy-efficient and scalable conversion into formate.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115544"},"PeriodicalIF":5.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-02DOI: 10.1016/j.cattod.2025.115541
So Hyeon Park , Tao Zhou , Seonggeun Park , Taekyung Yu , Jongsik Kim
Halloysite can be deprotonated and dehydrated to transform into polymorphic Kaolinite, whose non-reducible Al3+/Al4+ (MII3+/4+) are positioned adjacent to reducible Pdδ+/Agδ+ (MIδ+; δ≤2) to facilitate •H confinement in PdXAg4-X alloys (X=1–3) functioning as MIδ+ reservoirs for expediting H2 release. This is conducive to provoke water-gas shift (WGS) preferentially via redox mechanism that has been controversial in terms of rate-determining step (RDS) and major activator. To this end, Kaolinite-supported PdXAg4-X alloys were synthesized to impart MII3+/4+-O2--MIδ+-O2--MII3+/4+ interfaces, where the redox mechanism can be accelerated using MIδ+ or proximal oxygen vacancy (OV) as the main activator. The amounts and electron (e-) affinity of MIδ+/OV species varied with dissimilar X values or their exposure to hydro-thermal aging (HT) environments, thereby linking with WGS kinetic parameters of the catalysts. The hierarchies of the energy barriers for the HT-unsubjected/subjected catalysts were con-current to their trends on e- affinity with OV species rather than those with MIδ+ counterparts. This demonstrated that the RDS is either CO2 desorption from MIδ+/OV or H2O homolysis on OV. Moreover, the ranks of the collision frequencies for the HT-unsubjected/subjected catalysts exactly matched their trends on OV quantities rather than those on MIδ+ quantities. This indicated that OV sites outweigh MIδ+ species to accelerate the redox mechanism as the prime activators. This study uncovers how to design or regulate the catalytic surfaces for prompting the WGS exclusively via the redox mechanism.
{"title":"Revisiting rate-determining stage and prime activator for selective water-gas shift acceleration via redox mechanism","authors":"So Hyeon Park , Tao Zhou , Seonggeun Park , Taekyung Yu , Jongsik Kim","doi":"10.1016/j.cattod.2025.115541","DOIUrl":"10.1016/j.cattod.2025.115541","url":null,"abstract":"<div><div>Halloysite can be deprotonated and dehydrated to transform into polymorphic Kaolinite, whose non-reducible Al<sup>3+</sup>/Al<sup>4+</sup> (M<sub>II</sub><sup>3+/4+</sup>) are positioned adjacent to reducible Pd<sup>δ+</sup>/Ag<sup>δ+</sup> (M<sub>I</sub><sup>δ+</sup>; δ≤2) to facilitate •H confinement in Pd<sub>X</sub>Ag<sub>4-X</sub> alloys (X=1–3) functioning as M<sub>I</sub><sup>δ+</sup> reservoirs for expediting H<sub>2</sub> release. This is conducive to provoke water-gas shift (WGS) preferentially via redox mechanism that has been controversial in terms of rate-determining step (RDS) and major activator. To this end, Kaolinite-supported Pd<sub>X</sub>Ag<sub>4-X</sub> alloys were synthesized to impart M<sub>II</sub><sup>3+/4+</sup>-O<sup>2-</sup>-M<sub>I</sub><sup>δ+</sup>-O<sup>2-</sup>-M<sub>II</sub><sup>3+/4+</sup> interfaces, where the redox mechanism can be accelerated using M<sub>I</sub><sup>δ+</sup> or proximal oxygen vacancy (O<sub>V</sub>) as the main activator. The amounts and electron (e<sup>-</sup>) affinity of M<sub>I</sub><sup>δ+</sup>/O<sub>V</sub> species varied with dissimilar X values or their exposure to hydro-thermal aging (HT) environments, thereby linking with WGS kinetic parameters of the catalysts. The hierarchies of the energy barriers for the HT-unsubjected/subjected catalysts were con-current to their trends on e<sup>-</sup> affinity with O<sub>V</sub> species rather than those with M<sub>I</sub><sup>δ+</sup> counterparts. This demonstrated that the RDS is either CO<sub>2</sub> desorption from M<sub>I</sub><sup>δ+</sup>/O<sub>V</sub> or H<sub>2</sub>O homolysis on O<sub>V</sub>. Moreover, the ranks of the collision frequencies for the HT-unsubjected/subjected catalysts exactly matched their trends on O<sub>V</sub> quantities rather than those on M<sub>I</sub><sup>δ+</sup> quantities. This indicated that O<sub>V</sub> sites outweigh M<sub>I</sub><sup>δ+</sup> species to accelerate the redox mechanism as the prime activators. This study uncovers how to design or regulate the catalytic surfaces for prompting the WGS exclusively via the redox mechanism.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115541"},"PeriodicalIF":5.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new 6-fluoro-2-hydroxypyridinate (fhp)-bridged dirhodium(II) complex containing a 1,10-phenanthroline (phen) ligand, [Rh2(μ-fhp)3(η1-fhp)(phen)] (1), was prepared and characterized using nuclear magnetic resonance spectroscopy, electrospray ionization mass spectroscopy, elemental analysis, and synchrotron single crystal X-ray diffraction (SCXRD) analyses. In DMF, 1 was found to catalyze electrochemical proton reduction to evolve hydrogen in the presence of trifluoroacetic acid (Htfa) as a proton source. The turnover frequency and overpotential for hydrogen evolution catalyzed by 1 were 13263 s−1 and 457 mV, respectively. Interestingly, the intermediate species for the hydrogen evolution reaction, [Rh2(μ-fhp)3(phen)(η1-tfa)] (1-IM), could be crystallized from DMF solution of 1 in the presence of Htfa and was also characterized by synchrotron SCXRD. The reaction mechanism for the hydrogen evolution was thoroughly investigated based on the theoretically predicted redox potentials, pKa values, free energies, and binding energies. The findings are as follows: (i) the formation of the one-electron reduced species [1-IM]− serves as an initial trigger for hydrogen evolution; (ii) 1-IM transforms into a protonated species, which immediately undergoes one-electron reduction; (iii) initial protonation occurs at the axial position of the Rh2 core, followed by a second one-electron reduction, possibly through a concerted proton-electron transfer (CPET); and (iv) the final reaction intermediate was identified as [2Hax-Rh2(μ-fhp)3(phen)(η1-tfa)] ([2Hax-1-IM]), in which two protons are bound in a side-on fashion at the axial position of the Rh2 core, their coordination being assisted by the tfa ligand. These results indicated that 1-IM promotes the electrochemical hydrogen evolution via an ECEC mechanism (E: electron transfer, C: chemical reaction).
{"title":"Electrochemical hydrogen evolution and its reaction mechanism of hydroxypyridinate-bridged dirhodium(II) phenanthroline complex","authors":"Natsumi Yano, Kozo Sato, Makoto Handa, Yusuke Kataoka","doi":"10.1016/j.cattod.2025.115542","DOIUrl":"10.1016/j.cattod.2025.115542","url":null,"abstract":"<div><div>A new 6-fluoro-2-hydroxypyridinate (fhp)-bridged dirhodium(II) complex containing a 1,10-phenanthroline (phen) ligand, [Rh<sub>2</sub>(μ-fhp)<sub>3</sub>(η<sup>1</sup>-fhp)(phen)] (<strong>1</strong>), was prepared and characterized using nuclear magnetic resonance spectroscopy, electrospray ionization mass spectroscopy, elemental analysis, and synchrotron single crystal X-ray diffraction (SCXRD) analyses. In DMF, <strong>1</strong> was found to catalyze electrochemical proton reduction to evolve hydrogen in the presence of trifluoroacetic acid (Htfa) as a proton source. The turnover frequency and overpotential for hydrogen evolution catalyzed by <strong>1</strong> were 13263 s<sup>−1</sup> and 457 mV, respectively. Interestingly, the intermediate species for the hydrogen evolution reaction, [Rh<sub>2</sub>(μ-fhp)<sub>3</sub>(phen)(η<sup>1</sup>-tfa)] (<strong>1-IM</strong>), could be crystallized from DMF solution of <strong>1</strong> in the presence of Htfa and was also characterized by synchrotron SCXRD. The reaction mechanism for the hydrogen evolution was thoroughly investigated based on the theoretically predicted redox potentials, p<em>K</em>a values, free energies, and binding energies. The findings are as follows: (i) the formation of the one-electron reduced species <strong>[1-IM]</strong><sup><strong>−</strong></sup> serves as an initial trigger for hydrogen evolution; (ii) <strong>1-IM</strong> transforms into a protonated species, which immediately undergoes one-electron reduction; (iii) initial protonation occurs at the axial position of the Rh<sub>2</sub> core, followed by a second one-electron reduction, possibly through a concerted proton-electron transfer (CPET); and (iv) the final reaction intermediate was identified as [2H<sub>ax</sub>-Rh<sub>2</sub>(μ-fhp)<sub>3</sub>(phen)(η<sup>1</sup>-tfa)] (<strong>[2H</strong><sub><strong>ax</strong></sub><strong>-1-IM]</strong>), in which two protons are bound in a side-on fashion at the axial position of the Rh<sub>2</sub> core, their coordination being assisted by the tfa ligand. These results indicated that <strong>1-IM</strong> promotes the electrochemical hydrogen evolution via an ECEC mechanism (E: electron transfer, C: chemical reaction).</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115542"},"PeriodicalIF":5.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145009889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-02DOI: 10.1016/j.cattod.2025.115543
Clinton Manianglung , Daniel Owusu Asante , Young Soo Ko
This study investigates the influence of synthesis parameters on the morphology and catalytic activity of MgCl2-supported Ziegler–Natta (ZN) catalysts for ethylene polymerization. ZN catalysts were prepared under varied conditions, including reactor design modifications, solvent types and volumes, and TiCl4 feeding protocols. The notable differences in morphology, particle size, and Ti site density of the catalysts directly influenced their activity in slurry-phase polymerization experiments. Reactor design, particularly the inclusion of internal baffles, had the greatest impact, yielding more uniform morphology and higher activity. Dimensionless analysis confirmed that the triple-baffled flat-bottom reactor achieved turbulent flow (Re ≈ 2.2 × 10⁴) with minimal vortex formation (Fr ≈ 0.14) and a higher power number (Np) than other designs, indicating superior mixing. These parameters offer a basis for estimating energy requirements and scaling up. Solvent volume also emerged as a critical factor in mitigating agglomeration and improving active site distribution. Overall, reactor design, supported by computational fluid dynamics (CFD) and quantitative mixing analysis, together with optimized synthesis conditions, offers a practical route to enhance ZN catalyst performance for industrial applications.
{"title":"Effect of reactor design and synthesis parameters on the morphology and catalytic performance of MgCl2-supported Ziegler–Natta catalysts for ethylene polymerization","authors":"Clinton Manianglung , Daniel Owusu Asante , Young Soo Ko","doi":"10.1016/j.cattod.2025.115543","DOIUrl":"10.1016/j.cattod.2025.115543","url":null,"abstract":"<div><div>This study investigates the influence of synthesis parameters on the morphology and catalytic activity of MgCl<sub>2</sub>-supported Ziegler–Natta (ZN) catalysts for ethylene polymerization. ZN catalysts were prepared under varied conditions, including reactor design modifications, solvent types and volumes, and TiCl<sub>4</sub> feeding protocols. The notable differences in morphology, particle size, and Ti site density of the catalysts directly influenced their activity in slurry-phase polymerization experiments. Reactor design, particularly the inclusion of internal baffles, had the greatest impact, yielding more uniform morphology and higher activity. Dimensionless analysis confirmed that the triple-baffled flat-bottom reactor achieved turbulent flow (<em>Re</em> ≈ 2.2 × 10⁴) with minimal vortex formation (<em>Fr</em> ≈ 0.14) and a higher power number (<em>N<sub>p</sub></em>) than other designs, indicating superior mixing. These parameters offer a basis for estimating energy requirements and scaling up. Solvent volume also emerged as a critical factor in mitigating agglomeration and improving active site distribution. Overall, reactor design, supported by computational fluid dynamics (CFD) and quantitative mixing analysis, together with optimized synthesis conditions, offers a practical route to enhance ZN catalyst performance for industrial applications.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115543"},"PeriodicalIF":5.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145009890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.cattod.2025.115539
József S. Pap, Andrzej Kotarba, Małgorzata Witko, David Kubička
While target reactions in catalysis remain consistent, the approach to designing and developing new catalysts continually evolves. This evolution is driven by advancements in materials science and investigative methods, leading to a deeper understanding of structure-reactivity relationships. This interdisciplinary synergy is fundamental to catalyst design and the creation of novel catalytic materials.
{"title":"Guest editorial: Trends in catalyst design and novel catalytic materials","authors":"József S. Pap, Andrzej Kotarba, Małgorzata Witko, David Kubička","doi":"10.1016/j.cattod.2025.115539","DOIUrl":"10.1016/j.cattod.2025.115539","url":null,"abstract":"<div><div>While target reactions in catalysis remain consistent, the approach to designing and developing new catalysts continually evolves. This evolution is driven by advancements in materials science and investigative methods, leading to a deeper understanding of structure-reactivity relationships. This interdisciplinary synergy is fundamental to catalyst design and the creation of novel catalytic materials.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115539"},"PeriodicalIF":5.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of the hydroxyapatite (HA) contained in animal bone residues for the synthesis of active catalysts is an innovative solution to manage large quantities of bone waste (BW). In this study, two methods of preparing HA - containing catalysts were explored: i) conventional route using bone char (BC) from BW calcined at 500–900 °C, and ii) microwaves route using aqueous phase extraction from BW by a microwave (MW) -assisted process at 95 °C. BC mainly consisted of B-type HA, in which carbonate groups replace phosphate in the structure; however, its low surface area limited its catalytic performance. Modification with silica, MW treatment and surfactant charge had a critical effect on the formation of the porous structure, and consequently, on increasing the surface area of the composite catalysts. Cationic surfactants promoted silica network formation and resulted in improved porous structures due to their weaker interaction with the positively charged BC. The obtained HA-containing catalysts were demonstrated to be effective platforms for immobilising metallic species. Incorporating Ti and Zn by direct synthesis generated highly dispersed active sites, as confirmed by physicochemical characterization. Notably, an increase in sea buckthorn pyrolysis temperature (from 250 °C to 600 °C) was observed after just 5 min of MW irradiation using catalysts produced via the MW-assisted method, indicating enhanced heat transfer within the reactor. Meanwhile, catalysts produced via the conventional method significantly impacted the composition of the pyrolysis gas phase by promoting the formation of CO2 and hydrocarbons ≥C2, such as C2H2, C2H6, C3H8, C4H10, C5H12, and C6H14.
{"title":"Synthesis of hydroxyapatite – containing catalysts from bone waste – conventional route versus microwaves","authors":"Gabriela Petcu , Mariana Patrascu , Virginia-Cora Gheorghe , Gabriela Ionescu , Marilena Radoiu , Aneta Magdziarz , Cosmin Mărculescu","doi":"10.1016/j.cattod.2025.115538","DOIUrl":"10.1016/j.cattod.2025.115538","url":null,"abstract":"<div><div>The use of the hydroxyapatite (HA) contained in animal bone residues for the synthesis of active catalysts is an innovative solution to manage large quantities of bone waste (BW). In this study, two methods of preparing HA - containing catalysts were explored: i) conventional route using bone char (BC) from BW calcined at 500–900 °C, and ii) microwaves route using aqueous phase extraction from BW by a microwave (MW) -assisted process at 95 °C. BC mainly consisted of B-type HA, in which carbonate groups replace phosphate in the structure; however, its low surface area limited its catalytic performance. Modification with silica, MW treatment and surfactant charge had a critical effect on the formation of the porous structure, and consequently, on increasing the surface area of the composite catalysts. Cationic surfactants promoted silica network formation and resulted in improved porous structures due to their weaker interaction with the positively charged BC. The obtained HA-containing catalysts were demonstrated to be effective platforms for immobilising metallic species. Incorporating Ti and Zn by direct synthesis generated highly dispersed active sites, as confirmed by physicochemical characterization. Notably, an increase in sea buckthorn pyrolysis temperature (from 250 °C to 600 °C) was observed after just 5 min of MW irradiation using catalysts produced via the MW-assisted method, indicating enhanced heat transfer within the reactor. Meanwhile, catalysts produced via the conventional method significantly impacted the composition of the pyrolysis gas phase by promoting the formation of CO<sub>2</sub> and hydrocarbons ≥C<sub>2</sub>, such as C<sub>2</sub>H<sub>2</sub>, C<sub>2</sub>H<sub>6</sub>, C<sub>3</sub>H<sub>8</sub>, C<sub>4</sub>H<sub>10</sub>, C<sub>5</sub>H<sub>12</sub>, and C<sub>6</sub>H<sub>14</sub>.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115538"},"PeriodicalIF":5.3,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-29DOI: 10.1016/j.cattod.2025.115537
Adéla Olšovská , Martin Kamlar , Subhajyoti Samanta , Jan Veselý , Jiří Čejka , Michal Mazur
The Tsuji–Trost allylic alkylation is mainly performed in homogeneous systems; however, developing efficient alternative, heterogeneous catalysts remains crucial for sustainable synthesis. This study introduces zeolite-supported palladium catalysts as viable heterogeneous catalysts in this reaction. The active catalysts, Pd@USY and Pd@deAl-USY, were synthesized via controlled impregnation and reduction to achieve ultrasmall Pd nanoparticles (2.2 nm and 2.5 nm in diameter, respectively). Pd@lay-MFI, serving as a reference material containing large nanoparticles (>20 nm), proved inactive in the reaction. Among the prepared materials, Pd@USY exhibited optimal performance in the model Tsuji–Trost reaction between diethyl malonate and allyl acetate, achieving complete conversion within 2 h under mild conditions (room temperature, dichloromethane, K₂CO₃), with activity directly correlated to nanoparticle size: inactive Pd@lay-MFI featured substantially bigger particles, while sub-3 nm particles in active catalysts enabled efficient substrate activation. The reaction scope demonstrated broad substrate compatibility, though nucleophilicity and α-substitution heavily influenced reactivity, and bulky substituents reduced conversion due to zeolite pore diffusion constraints and steric hindrance during nucleophilic attack. Catalyst reuse was feasible for at least two cycles before the catalyst became deactivated. The analysis of the deactivation mechanism is ongoing. Notably, the loss of activity was reversible, as regeneration successfully restored catalytic performance. The catalyst was stable against sintering, leaching, or poisoning. In conclusion, Pd@USY represents a promising heterogeneous alternative for Tsuji–Trost allylic alkylation, combining high activity, selectivity, and operational simplicity.
{"title":"Zeolite-supported palladium nanoparticles as universal heterogeneous Tsuji–Trost allylic alkylation catalysts","authors":"Adéla Olšovská , Martin Kamlar , Subhajyoti Samanta , Jan Veselý , Jiří Čejka , Michal Mazur","doi":"10.1016/j.cattod.2025.115537","DOIUrl":"10.1016/j.cattod.2025.115537","url":null,"abstract":"<div><div>The Tsuji–Trost allylic alkylation is mainly performed in homogeneous systems; however, developing efficient alternative, heterogeneous catalysts remains crucial for sustainable synthesis. This study introduces zeolite-supported palladium catalysts as viable heterogeneous catalysts in this reaction. The active catalysts, Pd@USY and Pd@deAl-USY, were synthesized <em>via</em> controlled impregnation and reduction to achieve ultrasmall Pd nanoparticles (2.2 nm and 2.5 nm in diameter, respectively). Pd@lay-MFI, serving as a reference material containing large nanoparticles (>20 nm), proved inactive in the reaction. Among the prepared materials, Pd@USY exhibited optimal performance in the model Tsuji–Trost reaction between diethyl malonate and allyl acetate, achieving complete conversion within 2 h under mild conditions (room temperature, dichloromethane, K₂CO₃), with activity directly correlated to nanoparticle size: inactive Pd@lay-MFI featured substantially bigger particles, while sub-3 nm particles in active catalysts enabled efficient substrate activation. The reaction scope demonstrated broad substrate compatibility, though nucleophilicity and α-substitution heavily influenced reactivity, and bulky substituents reduced conversion due to zeolite pore diffusion constraints and steric hindrance during nucleophilic attack. Catalyst reuse was feasible for at least two cycles before the catalyst became deactivated. The analysis of the deactivation mechanism is ongoing. Notably, the loss of activity was reversible, as regeneration successfully restored catalytic performance. The catalyst was stable against sintering, leaching, or poisoning. In conclusion, Pd@USY represents a promising heterogeneous alternative for Tsuji–Trost allylic alkylation, combining high activity, selectivity, and operational simplicity.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"462 ","pages":"Article 115537"},"PeriodicalIF":5.3,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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