Pub Date : 2025-03-05DOI: 10.1016/j.jcat.2025.116056
Ting-Sheng Chen , Di Liu , Yun-Jie Li , Xing-Bao Wang , Chang-Hai Liang , Zhen-Yi Du , Wen-Ying Li
Controlling the oxygen-free product selectivity in catalytic hydrodeoxygenation is essential for producing high quality fuels from coal- and biomass-derived crude liquids. A series of boron-doped Ni/SiO2 catalysts were prepared for the efficient hydrodeoxygenation of dibenzofuran as a model compound. Boron doping significantly promoted the transformation of 2-cyclohexylcyclohexanol, which was accumulated as the main oxygen-containing intermediate compound on the pristine Ni/SiO2 catalyst, to the target products bicyclohexane and its isomer cyclopentylmethylcyclohexane. Characterization results show that boron doping increases Ni dispersion, modifies the electronic properties of Ni sites and in situ generates Brønsted acid sites by H2 spillover to boron oxides. The reduced Ni particle size improves the rates of dibenzofuran hydrogenation and 2-cyclohexylcyclohexanol dehydration. Electron-deficient Ni and boron oxides as the Lewis acid sites enhance the adsorption of 2-cyclohexylcyclohexanol. Furthermore, the in situ generated Brønsted acid sites favor the dehydration of 2-cyclohexylcyclohexanol, which gives the Ni-5B/SiO2 catalyst a better deoxygenation activity than the mechanical mixture of equal amounts of 5B/SiO2 and Ni/SiO2, as well as the one with a smaller Ni particle size of 3.8 nm.
{"title":"Promotional role of boron on Ni/SiO2 catalysts for dibenzofuran hydrodeoxygenation","authors":"Ting-Sheng Chen , Di Liu , Yun-Jie Li , Xing-Bao Wang , Chang-Hai Liang , Zhen-Yi Du , Wen-Ying Li","doi":"10.1016/j.jcat.2025.116056","DOIUrl":"10.1016/j.jcat.2025.116056","url":null,"abstract":"<div><div>Controlling the oxygen-free product selectivity in catalytic hydrodeoxygenation is essential for producing high quality fuels from coal- and biomass-derived crude liquids. A series of boron-doped Ni/SiO<sub>2</sub> catalysts were prepared for the efficient hydrodeoxygenation of dibenzofuran as a model compound. Boron doping significantly promoted the transformation of 2-cyclohexylcyclohexanol, which was accumulated as the main oxygen-containing intermediate compound on the pristine Ni/SiO<sub>2</sub> catalyst, to the target products bicyclohexane and its isomer cyclopentylmethylcyclohexane. Characterization results show that boron doping increases Ni dispersion, modifies the electronic properties of Ni sites and <em>in situ</em> generates Brønsted acid sites by H<sub>2</sub> spillover to boron oxides. The reduced Ni particle size improves the rates of dibenzofuran hydrogenation and 2-cyclohexylcyclohexanol dehydration. Electron-deficient Ni and boron oxides as the Lewis acid sites enhance the adsorption of 2-cyclohexylcyclohexanol. Furthermore, the <em>in situ</em> generated Brønsted acid sites favor the dehydration of 2-cyclohexylcyclohexanol, which gives the Ni-5B/SiO<sub>2</sub> catalyst a better deoxygenation activity than the mechanical mixture of equal amounts of 5B/SiO<sub>2</sub> and Ni/SiO<sub>2</sub>, as well as the one with a smaller Ni particle size of 3.8 nm.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"446 ","pages":"Article 116056"},"PeriodicalIF":6.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143560922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Herein, we report the efficient synthesis of E-enamines with 100% regioselectivity by the hydroamination of various terminal alkynes with secondary amines (piperidine and piperazine) mediated by easily accessible tungsten(0) complex, at smooth conditions. We have successfully broadened the hydroamination protocol to obtain various new E-divinylpiperazines with excellent regio- and stereoselectivities. The crystal structure of two of them was determined, which allowed receiving information, among others, on the conformation of the C–C double bond. Furthermore, the reaction allows facile access to enamines containing the isoindoline-1,3-dione fragment with high regioselectivity. Selected divinylpiperazines have also been investigated by photoluminescence excitation and emission examination. On the basis of the experimental results, the pathway of the catalytic hydroamination of alkyne with piperazine has been proposed.
{"title":"Hydroamination of terminal alkynes mediated by W(0) complex: A convenient tool for new enamines synthesis","authors":"Izabela Czeluśniak , Paulina Pąchalska , Joanna Trojan-Piegza , Mariusz Majchrzak , Miłosz Siczek , Teresa Szymańska-Buzar","doi":"10.1016/j.jcat.2025.116057","DOIUrl":"10.1016/j.jcat.2025.116057","url":null,"abstract":"<div><div>Herein, we report the efficient synthesis of <em>E</em>-enamines with 100% regioselectivity by the hydroamination of various terminal alkynes with secondary amines (piperidine and piperazine) mediated by easily accessible tungsten(0) complex, at smooth conditions. We have successfully broadened the hydroamination protocol to obtain various new <em>E</em>-divinylpiperazines with excellent regio- and stereoselectivities. The crystal structure of two of them was determined, which allowed receiving information, among others, on the conformation of the C–C double bond. Furthermore, the reaction allows facile access to enamines containing the isoindoline-1,3-dione fragment with high regioselectivity. Selected divinylpiperazines have also been investigated by photoluminescence excitation and emission examination. On the basis of the experimental results, the pathway of the catalytic hydroamination of alkyne with piperazine has been proposed.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"446 ","pages":"Article 116057"},"PeriodicalIF":6.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-04DOI: 10.1016/j.jcat.2025.116055
Yuan Wei , Chao Liu , Tian-Tian Wang , Hong-Yu Wang , Yu-Miao Yang , Gao-Feng Shi , Guo-Ying Wang
The rapid recombination rate of photogenerated charges presents considerable challenges for the rational design of high-performance, stable photocatalysts. In this study, we integrated the characteristics of oxygen doping and heterojunctions into oxygen-doped g-C3N4/BiOCl/Bi24O31Cl10 (OCN/BiOCl/Bi24O31Cl10) using a straightforward impregnation-calcination method. Oxygen doping disrupts the symmetric atomic arrangement in pure-phase samples, optimizing the electronic configuration of active sites at the reaction interface and enhancing the coupling between anions and cations. The introduction of BiOCl, which offers an excellent coordination environment, in conjunction with Bi24O31Cl10, creates a dual-S heterojunction. This structure establishes dual reaction interfaces that facilitate efficient dual electron ’transport channels,’ promoting the rapid transfer of charge carriers among OCN, BiOCl, and Bi24O31Cl10. Experimental results demonstrate that the OCN/BiOCl/Bi24O31Cl10 heterojunction material achieves a degradation efficiency of 96.1 % for 10 mg·L−1 levofloxacin under visible light. Notably, in situ measurements obtained through Kelvin probe force microscopy (KPFM) and density functional theory (DFT) calculations jointly reveal a unique chemical environment and electronic structure arising from the formation of an internal electric field among OCN, BiOCl, and Bi24O31Cl10, thereby providing enhanced pathways for the migration of photogenerated charge carriers. Furthermore, the heterostructure significantly reduces the transport distance of photogenically induced charges and decreases internal transport resistance, thereby improving the separation efficiency of photogenerated electron-hole pairs. This mechanism is crucial for the markedly enhanced photocatalytic degradation performance of OCN, BiOCl, and Bi24O31Cl10 materials. In summary, this work explores the synergistic effects among multiple modifications, providing insights for the precise design of efficient and stable photocatalytic degradation systems.
{"title":"The sandwich-shaped double S-scheme heterojuction OCN/BiOCl/Bi24O31Cl10 efficiently degrades levofloxacin and its charge transfer mechanism","authors":"Yuan Wei , Chao Liu , Tian-Tian Wang , Hong-Yu Wang , Yu-Miao Yang , Gao-Feng Shi , Guo-Ying Wang","doi":"10.1016/j.jcat.2025.116055","DOIUrl":"10.1016/j.jcat.2025.116055","url":null,"abstract":"<div><div>The rapid recombination rate of photogenerated charges presents considerable challenges for the rational design of high-performance, stable photocatalysts. In this study, we integrated the characteristics of oxygen doping and heterojunctions into oxygen-doped g-C<sub>3</sub>N<sub>4</sub>/BiOCl/Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub> (OCN/BiOCl/Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub>) using a straightforward impregnation-calcination method. Oxygen doping disrupts the symmetric atomic arrangement in pure-phase samples, optimizing the electronic configuration of active sites at the reaction interface and enhancing the coupling between anions and cations. The introduction of BiOCl, which offers an excellent coordination environment, in conjunction with Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub>, creates a dual-S heterojunction. This structure establishes dual reaction interfaces that facilitate efficient dual electron ’transport channels,’ promoting the rapid transfer of charge carriers among OCN, BiOCl, and Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub>. Experimental results demonstrate that the OCN/BiOCl/Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub> heterojunction material achieves a degradation efficiency of 96.1 % for 10 mg·L<sup>−1</sup> levofloxacin under visible light. Notably, in situ measurements obtained through Kelvin probe force microscopy (KPFM) and density functional theory (DFT) calculations jointly reveal a unique chemical environment and electronic structure arising from the formation of an internal electric field among OCN, BiOCl, and Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub>, thereby providing enhanced pathways for the migration of photogenerated charge carriers. Furthermore, the heterostructure significantly reduces the transport distance of photogenically induced charges and decreases internal transport resistance, thereby improving the separation efficiency of photogenerated electron-hole pairs. This mechanism is crucial for the markedly enhanced photocatalytic degradation performance of OCN, BiOCl, and Bi<sub>24</sub>O<sub>31</sub>Cl<sub>10</sub> materials. In summary, this work explores the synergistic effects among multiple modifications, providing insights for the precise design of efficient and stable photocatalytic degradation systems.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"446 ","pages":"Article 116055"},"PeriodicalIF":6.5,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-04DOI: 10.1016/j.jcat.2025.116051
Xiaolan Li , Jie Liu , Ruixin Song , Xuzhong Luo , Haiqing Luo
Rhodium(III)-catalyzed β-C(sp2)−H olefination and desilylative vinylation of acyclic enamides have been successfully achieved using vinylsilanes as coupling reagents. The reaction demonstrates effectiveness with a wide range of substrates, exhibiting high tolerance towards various functional groups. This protocol offers a practical approach for the synthesis of two kinds of dienamides, which were obtained in moderate to good yields with high stereoselectivity in both instances. Mechanistically, the β-C(sp2)−H activation was involved in this approach.
{"title":"Rhodium(III)-catalyzed selective C−H olefination and desilylative vinylation of acyclic enamides with vinylsilanes","authors":"Xiaolan Li , Jie Liu , Ruixin Song , Xuzhong Luo , Haiqing Luo","doi":"10.1016/j.jcat.2025.116051","DOIUrl":"10.1016/j.jcat.2025.116051","url":null,"abstract":"<div><div>Rhodium(III)-catalyzed β-C(sp<sup>2</sup>)−H olefination and desilylative vinylation of acyclic enamides have been successfully achieved using vinylsilanes as coupling reagents. The reaction demonstrates effectiveness with a wide range of substrates, exhibiting high tolerance towards various functional groups. This protocol offers a practical approach for the synthesis of two kinds of dienamides, which were obtained in moderate to good yields with high stereoselectivity in both instances. Mechanistically, the β-C(sp<sup>2</sup>)−H activation was involved in this approach.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"446 ","pages":"Article 116051"},"PeriodicalIF":6.5,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143547042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-03DOI: 10.1016/j.jcat.2025.116054
Zahra Almisbaa , Philippe Sautet
The feedstock of the ammonia decomposition reaction often contains water impurities. Water-induced Co oxidation leads to catalyst deactivation. DFT-based microkinetic simulations of ammonia decomposition and water dissociation reactions are used to understand oxygen poisoning on promoted and unpromoted Co surfaces. Simulations show that catalyst oxidation only occurs at low NH3 conversion and, at higher conversion, the produced H2 reduces the catalyst. Hence, in a typical flow reactor, catalyst oxidation is likely to occur only at the reactor inlet. However, the oxidized zone can slowly propagate along the reactor and impact the catalyst stability. The adsorption of oxygen was stronger on BaO-promoted Co in comparison to pristine Co. However, Co-BaO is more sensitive to H2 pressure and needs a lower ammonia conversion to prevent oxygen poisoning on the surface. This indicates that the BaO promoter plays a role in making the catalyst more resistant to O-induced poisoning during the ammonia decomposition reaction.
{"title":"Effect of water impurities on promoted and unpromoted cobalt-catalysts during the ammonia decomposition reaction","authors":"Zahra Almisbaa , Philippe Sautet","doi":"10.1016/j.jcat.2025.116054","DOIUrl":"10.1016/j.jcat.2025.116054","url":null,"abstract":"<div><div>The feedstock of the ammonia decomposition reaction often contains water impurities. Water-induced Co oxidation leads to catalyst deactivation. DFT-based microkinetic simulations of ammonia decomposition and water dissociation reactions are used to understand oxygen poisoning on promoted and unpromoted Co surfaces. Simulations show that catalyst oxidation only occurs at low NH<sub>3</sub> conversion and, at higher conversion, the produced H<sub>2</sub> reduces the catalyst. Hence, in a typical flow reactor, catalyst oxidation is likely to occur only at the reactor inlet. However, the oxidized zone can slowly propagate along the reactor and impact the catalyst stability. The adsorption of oxygen was stronger on BaO-promoted Co in comparison to pristine Co. However, Co-BaO is more sensitive to H<sub>2</sub> pressure and needs a lower ammonia conversion to prevent oxygen poisoning on the surface. This indicates that the BaO promoter plays a role in making the catalyst more resistant to O-induced poisoning during the ammonia decomposition reaction.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"446 ","pages":"Article 116054"},"PeriodicalIF":6.5,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-02DOI: 10.1016/j.jcat.2025.116053
Jia Li , Yang Li , Yingshan Zeng , Yang Liu , Zhengguo Song , Zhi Liu
CO2 photo reduction provides a feasible technique to solve climate issues and promote carbon neutrality. However, the efficiency of CO2 photo reduction is severely depressed by the rapid recombination of photo generated carriers within photo catalysts, restricting the participation of electrons in the reduction process. In this study, we successfully construct a two-dimensional (2D) multilayer internal electric field (IEF) heterostructure by engineering the interface between NiAl-LDH and ZnV2O6 (ZNA). Driven by the IEF, the separation of photo generated electron-hole pairs is significantly enhanced, leading to the increased utilization efficiency of carriers for active sites. The best-performing sample of ZNA-2 achieves a highest CO yield of 695.8 μmol g−1, approximately 30.5-fold higher than that of pristine ZnV2O6. Photo electrochemical measurement and density functional theory (DFT) calculation results reveal that the 2D-2D stacked structure generates multiple interlayer built-in electric fields, which are crucial for enhancing carrier separation and suppressing recombination. Adsorption energy and intermediate COOH* analysis reveal that ZNA-2 significantly lowers the adsorption energy of CO2, promoting its stable adsorption and subsequent conversion. Moreover, the unique 2D multilayer IEF heterostructure greatly facilitates the formation of key intermediate COOH* and the desorption of CO during CO2 photo reduction, leading to high CO activity and selectivity. The present work discloses the unprecedented potential of 2D multilayer IEF heterostructures for efficient CO2 photo reduction, marking a significant advancement over conventional 2D counterparts.
{"title":"Engineering two-dimensional multilayer heterostructure of internal electric field to enhance CO2 photoreduction","authors":"Jia Li , Yang Li , Yingshan Zeng , Yang Liu , Zhengguo Song , Zhi Liu","doi":"10.1016/j.jcat.2025.116053","DOIUrl":"10.1016/j.jcat.2025.116053","url":null,"abstract":"<div><div>CO<sub>2</sub> photo reduction provides a feasible technique to solve climate issues and promote carbon neutrality. However, the efficiency of CO<sub>2</sub> photo reduction is severely depressed by the rapid recombination of photo generated carriers within photo catalysts, restricting the participation of electrons in the reduction process. In this study, we successfully construct a two-dimensional (2D) multilayer internal electric field (IEF) heterostructure by engineering the interface between NiAl-LDH and ZnV<sub>2</sub>O<sub>6</sub> (ZNA). Driven by the IEF, the separation of photo generated electron-hole pairs is significantly enhanced, leading to the increased utilization efficiency of carriers for active sites. The best-performing sample of ZNA-2 achieves a highest CO yield of 695.8 μmol g<sup>−1</sup>, approximately 30.5-fold higher than that of pristine ZnV<sub>2</sub>O<sub>6</sub>. Photo electrochemical measurement and density functional theory (DFT) calculation results reveal that the 2D-2D stacked structure generates multiple interlayer built-in electric fields, which are crucial for enhancing carrier separation and suppressing recombination. Adsorption energy and intermediate COOH* analysis reveal that ZNA-2 significantly lowers the adsorption energy of CO<sub>2</sub>, promoting its stable adsorption and subsequent conversion. Moreover, the unique 2D multilayer IEF heterostructure greatly facilitates the formation of key intermediate COOH* and the desorption of CO during CO<sub>2</sub> photo reduction, leading to high CO activity and selectivity. The present work discloses the unprecedented potential of 2D multilayer IEF heterostructures for efficient CO<sub>2</sub> photo reduction, marking a significant advancement over conventional 2D counterparts.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"445 ","pages":"Article 116053"},"PeriodicalIF":6.5,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-28DOI: 10.1016/j.jcat.2025.116050
Wangjun Guo , Jianqun Liu , Hongli Liu , Yadong Liu , Zhisheng Wu , Minchang Wang , Yi Niu
In recent years, transition-metal-catalyzed CN bond formation from nitroarenes and aryl Grignard reagents has emerged as a promising and highly efficient method. Despite this, dinitro aromatic compounds have received limited attention in this context. Herein, we disclose a novel approach for synthesizing diarylamines via Ni-catalyzed cross-coupling of Grignard reagents with both mono- and di-nitro aromatic compounds. This method demonstrates remarkable tolerance towards a wide range of functional groups, including COOEt, F, Cl, CN, CF3, OCF3, SCH3, and pyridyl groups, allowing for the synthesis of various aminated arenes in moderate to good yields. This CN bond formation method offers a general and step-economical pathway to diaryl and polyaryl amines, paving the way for new synthetic possibilities.
{"title":"Nickel-catalyzed CN bond formation of diarylamine between nitroarenes and aryl Grignard reagents","authors":"Wangjun Guo , Jianqun Liu , Hongli Liu , Yadong Liu , Zhisheng Wu , Minchang Wang , Yi Niu","doi":"10.1016/j.jcat.2025.116050","DOIUrl":"10.1016/j.jcat.2025.116050","url":null,"abstract":"<div><div>In recent years, transition-metal-catalyzed C<img>N bond formation from nitroarenes and aryl Grignard reagents has emerged as a promising and highly efficient method. Despite this, dinitro aromatic compounds have received limited attention in this context. Herein, we disclose a novel approach for synthesizing diarylamines <em>via</em> Ni-catalyzed cross-coupling of Grignard reagents with both mono- and di-nitro aromatic compounds. This method demonstrates remarkable tolerance towards a wide range of functional groups, including COOEt, F, Cl, CN, CF<sub>3</sub>, OCF<sub>3</sub>, SCH<sub>3</sub>, and pyridyl groups, allowing for the synthesis of various aminated arenes in moderate to good yields. This C<img>N bond formation method offers a general and step-economical pathway to diaryl and polyaryl amines, paving the way for new synthetic possibilities.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"445 ","pages":"Article 116050"},"PeriodicalIF":6.5,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-28DOI: 10.1016/j.jcat.2025.116052
Hong Yong Sohn , Bahador Abolpour
The shape of a catalyst pellet affects the overall rate of reaction when the reaction is influenced by mass and heat transfer processes. While traditional modeling approaches often assume simple, basic pellet shapes (such as spheres or cylinders), this work focused on the numerical modeling of catalyst pellets with non-basic geometries, which are commonly used in industry. Using numerical techniques, the effectiveness factors of catalyst pellets with various non-basic shapes as functions of the Thiele modulus were investigated. Results indicate that the effectiveness factors of catalyst pellets of non-basic shapes, such as a hollow cylinder, cone, parallelepiped and finite cylinder with hemispherical caps, may be given by a single relationship with a generalized Thiele modulus λp, much as for the cases of basic shapes of a sphere, a long cylinder and a flat slab. This definition of the generalized modulus further provides unified numerical criteria for negligible effects of pore diffusion as λp ≤ 0.3 where within ∼10 % error (or λp ≤ 0.1 if an accuracy within ∼1 % is required) and for reaching large λp asymptotic condition as λp ≥ 3 where within ∼10 % error (or λp ≥ 10 if an accuracy within ∼1 % is required). Finally, for any shape of the catalyst pellets, the effectiveness factor can be expressed by the following single equation:
{"title":"Effectiveness factor for catalyst pellets of non-basic shapes","authors":"Hong Yong Sohn , Bahador Abolpour","doi":"10.1016/j.jcat.2025.116052","DOIUrl":"10.1016/j.jcat.2025.116052","url":null,"abstract":"<div><div>The shape of a catalyst pellet affects the overall rate of reaction when the reaction is influenced by mass and heat transfer processes. While traditional modeling approaches often assume simple, basic pellet shapes (such as spheres or cylinders), this work focused on the numerical modeling of catalyst pellets with non-basic geometries, which are commonly used in industry. Using numerical techniques, the effectiveness factors of catalyst pellets with various non-basic shapes as functions of the Thiele modulus were investigated. Results indicate that the effectiveness factors of catalyst pellets of non-basic shapes, such as a hollow cylinder, cone, parallelepiped and finite cylinder with hemispherical caps, may be given by a single relationship with a generalized Thiele modulus <em>λ<sub>p</sub></em>, much as for the cases of basic shapes of a sphere, a long cylinder and a flat slab. This definition of the generalized modulus further provides unified numerical criteria for negligible effects of pore diffusion as <em>λ<sub>p</sub></em> ≤ 0.3 where <span><math><mrow><mi>E</mi><mo>≈</mo><mn>1</mn></mrow></math></span> within ∼10 % error (or <em>λ<sub>p</sub></em> ≤ 0.1 if an accuracy within ∼1 % is required) and for reaching large <em>λ<sub>p</sub></em> asymptotic condition as <em>λ<sub>p</sub></em> ≥ 3 where <span><math><mrow><mi>E</mi><mo>≈</mo><mfrac><mn>1</mn><msub><mi>λ</mi><mi>p</mi></msub></mfrac></mrow></math></span> within ∼10 % error (or <em>λ<sub>p</sub></em> ≥ 10 if an accuracy within ∼1 % is required). Finally, for any shape of the catalyst pellets, the effectiveness factor can be expressed by the following single equation:</div><div><span><math><mrow><mi>E</mi><mo>=</mo><mfrac><mn>1</mn><msqrt><mrow><mn>1</mn><mo>+</mo><msubsup><mi>λ</mi><mrow><mi>p</mi></mrow><mn>2</mn></msubsup></mrow></msqrt></mfrac></mrow></math></span></div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"445 ","pages":"Article 116052"},"PeriodicalIF":6.5,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-27DOI: 10.1016/j.jcat.2025.116030
Shiyue Li , Robert Pestman , A. Iulian Dugulan , Zhuowu Men , Peng Wang , Emiel J.M. Hensen
The removal of carbon deposits from carburized Fe-based Fischer–Tropsch catalysts is a critical aspect of their performance. In this study, a method is presented to remove carbon deposits from freshly prepared χ-Fe5C2. The method involves successive passivation and reduction steps, which do not affect the bulk structure of the χ-Fe5C2 catalyst. The passivation step transforms the carbonaceous deposits from a graphitic structure to a disordered oxygen-functionalized structure, facilitating its removal by a reduction step in hydrogen. This results in a higher initial activity of the catalyst and substantially shortens the induction period observed without such pretreatment. The findings underscore the possibility of improving catalytic performance of Fe-carbides by changing the structure and reactivity of carbonaceous deposits.
{"title":"Removal of carbon deposits on χ-Fe5C2 Fischer–Tropsch catalysts","authors":"Shiyue Li , Robert Pestman , A. Iulian Dugulan , Zhuowu Men , Peng Wang , Emiel J.M. Hensen","doi":"10.1016/j.jcat.2025.116030","DOIUrl":"10.1016/j.jcat.2025.116030","url":null,"abstract":"<div><div>The removal of carbon deposits from carburized Fe-based Fischer–Tropsch catalysts is a critical aspect of their performance. In this study, a method is presented to remove carbon deposits from freshly prepared χ-Fe<sub>5</sub>C<sub>2</sub>. The method involves successive passivation and reduction steps, which do not affect the bulk structure of the χ-Fe<sub>5</sub>C<sub>2</sub> catalyst. The passivation step transforms the carbonaceous deposits from a graphitic structure to a disordered oxygen-functionalized structure, facilitating its removal by a reduction step in hydrogen. This results in a higher initial activity of the catalyst and substantially shortens the induction period observed without such pretreatment. The findings underscore the possibility of improving catalytic performance of Fe-carbides by changing the structure and reactivity of carbonaceous deposits.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"445 ","pages":"Article 116030"},"PeriodicalIF":6.5,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143507460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-27DOI: 10.1016/j.jcat.2025.116049
Qiang Li , Ying Chen , Jian Luo , Xiaobing Lu , Xiao Luo , Jingpeng Cai , Peipei Wang , Wuli Han , Yufan Lan
With the increasingly stringent environmental rules around the world, new drilling fluid additives having high efficiency, non-biotoxicity and low cost by green synthesis strategy will be the developing trends. Herein, under acting on the prefabricated MIL-Fe/NH2-D(5) photocatalyst, the photo-induced detoxification of toxic sulfonated phenolic resin (SMP-3) was successfully completed for the first time, which further photopolymerized with tea polyphenol (TP), acrylamide (AM) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) to prepare eco-friendly fluid loss agent LI-3. The homemade MIL-Fe/NH2-D(5) demonstrates dramatically increased light absorption in UV–VIS-NIR range with a significantly reduced band gap of 1.68 eV, and exhibits excellent efficiency of separating interface charges with rapid transfer dynamic. As expected, LI-3 filtrate reducer effectively controls the rheology of slurry, and possesses excellent loss-reducing properties even at high temperatures and high salinity conditions. Compared with base mud, the filtrate volumes of LI-3/BT-WBDFs containing 2.0 % LI-3 are reduced by 83.91 % and 83.42 % before and after aging at 180 °C, respectively. Finally, the possible mechanisms involved are explored. Particularly in both photo-induced detoxification and green synthesis periods, the photo thermal conversion based on localized surface plasmon resonance (LSPR) ensures mild conditions with energy saving.
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