Yingxin Guo , Ming Gong , Xin Xu , Yuming Dong , Guangli Wang
The photocatalytic oxidation of biomass-derived structural units such as 5-hydroxymethylfurfural is a promising reaction for obtaining valuable chemicals and effectively storing solar radiation for long periods. In this work, we developed a Bi24O29Br10(WO4)2 solid solution photocatalyst for the selective oxidation of 5-hydroxymethylfurfural to produce 2,5-diformylfuran. The doping of WO42− allows for effective separation of photogenerated charges, thereby enhancing the utilization of both photogenerated holes and reactive oxygen species in the reaction. Under optimal conditions, the conversion rate of 5-hydroxymethylfurfural reached 98.9%, and the selectivity for 2,5-diformylfuran reached 92.5%, making it one of the best-performing photocatalytic systems in this field. This work provides a new strategy for the development of efficient bismuth-based photocatalysts for selective oxidation in organic reactions.
{"title":"Efficient photocatalytic selective oxidation of 5-hydroxymethylfurfural on Bi24O29Br10(WO4)2 solid solution via enhanced charge separation†","authors":"Yingxin Guo , Ming Gong , Xin Xu , Yuming Dong , Guangli Wang","doi":"10.1039/d4cy01420k","DOIUrl":"10.1039/d4cy01420k","url":null,"abstract":"<div><div>The photocatalytic oxidation of biomass-derived structural units such as 5-hydroxymethylfurfural is a promising reaction for obtaining valuable chemicals and effectively storing solar radiation for long periods. In this work, we developed a Bi<sub>24</sub>O<sub>29</sub>Br<sub>10</sub>(WO<sub>4</sub>)<sub>2</sub> solid solution photocatalyst for the selective oxidation of 5-hydroxymethylfurfural to produce 2,5-diformylfuran. The doping of WO<sub>4</sub><sup>2−</sup> allows for effective separation of photogenerated charges, thereby enhancing the utilization of both photogenerated holes and reactive oxygen species in the reaction. Under optimal conditions, the conversion rate of 5-hydroxymethylfurfural reached 98.9%, and the selectivity for 2,5-diformylfuran reached 92.5%, making it one of the best-performing photocatalytic systems in this field. This work provides a new strategy for the development of efficient bismuth-based photocatalysts for selective oxidation in organic reactions.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1061-1069"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430625","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}
Vera P. Santos , Ewa Tocha , Jin Yang , Mark McAdon , Carla Schmidt , Stuart Leadley , David Yancey , Stefan van Bloois , Joost Depicker , Swati Naik , Linh Bui , Saurabh Bhandari , Daniel Grohol , David G. Barton
Unexpected changes in catalyst performance can have a significant impact on manufacturing plant operations with respect to both economics and sustainability. The useful lifespan of a catalyst is influenced by various factors, including catalyst performance aging (activity and selectivity), or the mechanical damage of catalyst pellets leading to high reactor pressure drops. Deactivation of industrial catalysts often results from thermal (metal sintering, loss of active surface areas, and vaporization), chemical (poisons: inorganic and organic and fouling), and mechanical mechanisms (abrasion, fracture, and dusting). Conducting a proper root-cause analysis can be complex and typically requires multidimensional fundamental scientific approaches. This study illustrates the mechanical degradation of CuZnO catalyst pellets under industrial hydrogenation conditions, leading to an increased pressure drop and reduced catalyst lifetime. Post-mortem analysis at different length scales in combination with the development of accelerating aging tools played a substantial role in the identification of catalyst failure modes for these industrial catalysts. Careful interpretation of the microscopy results enabled the identification of characteristic fingerprints of the failure mechanism. The presence of organic chloride impurities in the feed in combination with a reducing atmosphere accelerated both the sintering of ZnO and deformation of the catalyst pills. This reduced the effective lifespan of the catalyst, as the decrease in particle void fractions led to an increased reactor pressure drop, eventually necessitating the reloading of the reactor with a fresh catalyst. Understanding these mechanisms at both micro and macro scales is crucial for improving the economics and sustainability of commercial operations.
{"title":"Unravelling the deactivation of CuZnO-based catalysts at the industrial scale: a micro to macro scale perspective†","authors":"Vera P. Santos , Ewa Tocha , Jin Yang , Mark McAdon , Carla Schmidt , Stuart Leadley , David Yancey , Stefan van Bloois , Joost Depicker , Swati Naik , Linh Bui , Saurabh Bhandari , Daniel Grohol , David G. Barton","doi":"10.1039/d4cy01323a","DOIUrl":"10.1039/d4cy01323a","url":null,"abstract":"<div><div>Unexpected changes in catalyst performance can have a significant impact on manufacturing plant operations with respect to both economics and sustainability. The useful lifespan of a catalyst is influenced by various factors, including catalyst performance aging (activity and selectivity), or the mechanical damage of catalyst pellets leading to high reactor pressure drops. Deactivation of industrial catalysts often results from thermal (metal sintering, loss of active surface areas, and vaporization), chemical (poisons: inorganic and organic and fouling), and mechanical mechanisms (abrasion, fracture, and dusting). Conducting a proper root-cause analysis can be complex and typically requires multidimensional fundamental scientific approaches. This study illustrates the mechanical degradation of CuZnO catalyst pellets under industrial hydrogenation conditions, leading to an increased pressure drop and reduced catalyst lifetime. Post-mortem analysis at different length scales in combination with the development of accelerating aging tools played a substantial role in the identification of catalyst failure modes for these industrial catalysts. Careful interpretation of the microscopy results enabled the identification of characteristic fingerprints of the failure mechanism. The presence of organic chloride impurities in the feed in combination with a reducing atmosphere accelerated both the sintering of ZnO and deformation of the catalyst pills. This reduced the effective lifespan of the catalyst, as the decrease in particle void fractions led to an increased reactor pressure drop, eventually necessitating the reloading of the reactor with a fresh catalyst. Understanding these mechanisms at both micro and macro scales is crucial for improving the economics and sustainability of commercial operations.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1055-1060"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430627","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}
Paulla B. F. Sousa , Elise M. Albuquerque , Marco A. Fraga , Heloise O. Pastore
While framework-Al (AlTd) sites on [Al]-RUB-18 materials with Brønsted acidity were active in ethanol dehydration, the acidity of partial framework-Al sites (AlOh or aluminol sites) remains unknown. 31P-MAS-NMR of adsorbed trimethylphosphine oxide (TMPO) was used together with catalytic reactions, in the presence and absence of water, to elucidate the acidity features of aluminol sites on lamellar RUB-18. Herein, spectroscopic analysis indicates that the 31P signals arise from TMPO adsorbed on the lamella surface of RUB-18 (δ31P = 40–49 ppm), silanol/aluminol sites (δ31P = 49–56 ppm), and Brønsted acid sites (60–75 ppm). The crystallinity degree of the structure, Si/Al and AlTd/AlOh molar ratios, and TMPO loadings, under wet and dry conditions, all lead to changes in 31P resonances. Two resonance signals at 64 ppm and 69 ppm were attributed to partial and complete framework-Al sites, respectively. A clear correlation between the adsorption capacity of the active sites and peak intensities in the BAS region proves the influence of water in the adsorption process. This study brings additional evidence that the (SiO4)4Al and (SiO4)3Al–(OH)(H2O)2 species played a crucial role in biomass-derivative conversion reactions. The simultaneous activity of Brønsted/Lewis acid sites was revealed, with the possibility of the (SiO4)3Al–(OH)(H2O)2 sites acting as LAS. The present study clarifies the acidity features of aluminol sites on lamellar [Al]-RUB-18 and brings attention to the evaluation of solid catalysts under aqueous-phase conditions.
{"title":"Partial framework-Al in lamellar H-[Al]-RUB-18: acidity by probe TMPO adsorption and catalytic study in the presence and absence of water†","authors":"Paulla B. F. Sousa , Elise M. Albuquerque , Marco A. Fraga , Heloise O. Pastore","doi":"10.1039/d4cy01288g","DOIUrl":"10.1039/d4cy01288g","url":null,"abstract":"<div><div>While framework-Al (Al<sub>Td</sub>) sites on [Al]-RUB-18 materials with Brønsted acidity were active in ethanol dehydration, the acidity of partial framework-Al sites (Al<sub>Oh</sub> or aluminol sites) remains unknown. <sup>31</sup>P-MAS-NMR of adsorbed trimethylphosphine oxide (TMPO) was used together with catalytic reactions, in the presence and absence of water, to elucidate the acidity features of aluminol sites on lamellar RUB-18. Herein, spectroscopic analysis indicates that the <sup>31</sup>P signals arise from TMPO adsorbed on the lamella surface of RUB-18 (<em>δ</em><sub><sup>31</sup>P</sub> = 40–49 ppm), silanol/aluminol sites (<em>δ</em><sub><sup>31</sup>P</sub> = 49–56 ppm), and Brønsted acid sites (60–75 ppm). The crystallinity degree of the structure, Si/Al and Al<sub>Td</sub>/Al<sub>Oh</sub> molar ratios, and TMPO loadings, under wet and dry conditions, all lead to changes in <sup>31</sup>P resonances. Two resonance signals at 64 ppm and 69 ppm were attributed to partial and complete framework-Al sites, respectively. A clear correlation between the adsorption capacity of the active sites and peak intensities in the BAS region proves the influence of water in the adsorption process. This study brings additional evidence that the (SiO<sub>4</sub>)<sub>4</sub>Al and (SiO<sub>4</sub>)<sub>3</sub>Al–(OH)(H<sub>2</sub>O)<sub>2</sub> species played a crucial role in biomass-derivative conversion reactions. The simultaneous activity of Brønsted/Lewis acid sites was revealed, with the possibility of the (SiO<sub>4</sub>)<sub>3</sub>Al–(OH)(H<sub>2</sub>O)<sub>2</sub> sites acting as LAS. The present study clarifies the acidity features of aluminol sites on lamellar [Al]-RUB-18 and brings attention to the evaluation of solid catalysts under aqueous-phase conditions.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1157-1173"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430647","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}
Chisom S. Egedeuzu , Peter G. Taylor , Lu Shin Wong
Silyl ethers are an important group of compounds containing Si–O bonds with a variety of applications, but their formation currently relies on reagents that are undesirable from a sustainability perspective. This study is a further investigation of the biocatalytic silylation of alcohols using silanols or silyl ethers as the silyl donor, with the recombinant enzyme silicatein-α as the catalyst. It was found that the model enzyme-catalysed reactions gave better conversion of phenol to its corresponding phenoxy silane compared to the aliphatic n-octanol. The enzyme was selective for phenols and did not catalyse disiloxane formation. In addition, it was observed that the optimum temperature for the enzymatic conversion was 75 °C. The enzyme also showed superior catalysis compared to conventional small molecule base catalysts such as imidazole and triethylamine.
{"title":"Investigating silicatein selectivity and specificity in silicon–oxygen bond condensation and metathesis†","authors":"Chisom S. Egedeuzu , Peter G. Taylor , Lu Shin Wong","doi":"10.1039/d4cy00985a","DOIUrl":"10.1039/d4cy00985a","url":null,"abstract":"<div><div>Silyl ethers are an important group of compounds containing Si–O bonds with a variety of applications, but their formation currently relies on reagents that are undesirable from a sustainability perspective. This study is a further investigation of the biocatalytic silylation of alcohols using silanols or silyl ethers as the silyl donor, with the recombinant enzyme silicatein-α as the catalyst. It was found that the model enzyme-catalysed reactions gave better conversion of phenol to its corresponding phenoxy silane compared to the aliphatic <em>n</em>-octanol. The enzyme was selective for phenols and did not catalyse disiloxane formation. In addition, it was observed that the optimum temperature for the enzymatic conversion was 75 °C. The enzyme also showed superior catalysis compared to conventional small molecule base catalysts such as imidazole and triethylamine.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1009-1015"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/cy/d4cy00985a?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430622","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 selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) is becoming increasingly attractive for the industrial production of polyglycolic acid (PGA) biodegradable plastics. However, it is still necessary to develop highly selective/active and affordable DMO hydrogenation catalysts for the large-scale production of MG and PGA. In this report, silica-supported Ni–Co alloy catalysts were meticulously investigated for the selective hydrogenation of dimethyl oxalate to methyl glycolate. Compared with monometallic Ni or Co, the supported Ni–Co alloy catalysts with an appropriate doping of Co in Ni resulted in the significant promotion of dimethyl oxalate conversion and methyl glycolate selectivity at mild temperature (180 °C). Optimized dimethyl oxalate conversion and selectivity for methyl glycolate were 87% and 86%, respectively, on the 15Ni–10Co/SiO2 catalyst. The promotion of dimethyl oxalate conversion was attributed to the large capacity and strong strength of hydrogen adsorption, as proven via H2-TPD, and the active sites with uniform strength for CO adsorption and dimethyl oxalate (or key oxygenated intermediates) adsorption, as proven via in situ CO-DRIFTS. These phenomena were enhanced by the effective interaction between Ni and Co. Furthermore, it was found that the strength of acid sites has an influence on product selectivity control for ethanol and methyl formate; particularly, the synergy between the acid sites and metal sites may facilitate deep hydrogenation of dimethyl oxalate to form unexpected methyl formate. This study not only shows the catalytic behavior of dimethyl oxalate hydrogenation on non-precious Ni–Co alloy catalysts but also provides new insights into designing Ni-based catalysts for the selective hydrogenation of oxygenates with multiple ester groups.
{"title":"An examination of dimethyl oxalate hydrogenation to methyl glycolate on silica-supported Ni–Co alloy catalysts†","authors":"Donghui Xiao , Shilong Xie , Xin Gao , Riguang Zhang , Chun-Ran Chang","doi":"10.1039/d4cy01278j","DOIUrl":"10.1039/d4cy01278j","url":null,"abstract":"<div><div>The selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) is becoming increasingly attractive for the industrial production of polyglycolic acid (PGA) biodegradable plastics. However, it is still necessary to develop highly selective/active and affordable DMO hydrogenation catalysts for the large-scale production of MG and PGA. In this report, silica-supported Ni–Co alloy catalysts were meticulously investigated for the selective hydrogenation of dimethyl oxalate to methyl glycolate. Compared with monometallic Ni or Co, the supported Ni–Co alloy catalysts with an appropriate doping of Co in Ni resulted in the significant promotion of dimethyl oxalate conversion and methyl glycolate selectivity at mild temperature (180 °C). Optimized dimethyl oxalate conversion and selectivity for methyl glycolate were 87% and 86%, respectively, on the 15Ni–10Co/SiO<sub>2</sub> catalyst. The promotion of dimethyl oxalate conversion was attributed to the large capacity and strong strength of hydrogen adsorption, as proven <em>via</em> H<sub>2</sub>-TPD, and the active sites with uniform strength for CO adsorption and dimethyl oxalate (or key oxygenated intermediates) adsorption, as proven <em>via in situ</em> CO-DRIFTS. These phenomena were enhanced by the effective interaction between Ni and Co. Furthermore, it was found that the strength of acid sites has an influence on product selectivity control for ethanol and methyl formate; particularly, the synergy between the acid sites and metal sites may facilitate deep hydrogenation of dimethyl oxalate to form unexpected methyl formate. This study not only shows the catalytic behavior of dimethyl oxalate hydrogenation on non-precious Ni–Co alloy catalysts but also provides new insights into designing Ni-based catalysts for the selective hydrogenation of oxygenates with multiple ester groups.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1041-1054"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430626","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}
Xiyue Lu , Hui Wang , Wei Liu , Mooeez ur Rehman , Lu Wang , Yan Xu , Shengnian Wang , Yujun Zhao
Effective non-noble metal catalysts are critical for upgrading lignin-derived compounds into valuable products by hydrodeoxygenation (HDO). In this study, new Ni0–NiNbOx/SiO2 catalysts were synthesized by combining sol–gel and impregnation methods. The HDO performance of these catalysts was then evaluated in the production of cycloalkanes from lignin-derived phenolic compounds. These Ni0–NiNbOx/SiO2 catalysts present a considerably larger specific surface area than their Ni/SiO2 counterparts. They work as bifunctional catalysts in the HDO process, where Ni0 species act as active sites for hydrogenation while NiNbOx provides the Lewis acid sites necessary for deoxygenation. In this way, a significant improvement in the cyclohexane yield from 18% to 94.4% in guaiacol HDO was achieved on these Ni0–NiNbOx/SiO2 catalysts. The best catalyst 10Ni/20Nb@SiO2 exhibits complete conversion of guaiacol and almost 100% selectivity of cycloalkanes at 250 °C. The apparent activation energy for the 10Ni/20Nb@SiO2 catalyst was identified to be 54.2 kJ mol−1, notably lower than that for other reported Ni-based catalysts. These findings highlight the superior performance of Ni0–NiNbOx/SiO2 catalysts in the HDO of lignin-derived phenolic compounds, underscoring their great potential in producing cycloalkanes from renewable resources. Our efforts help pave the way for the catalytic transformation of lignin into valuable biofuels to advance the global mission toward a sustainable supply of fuels.
{"title":"The promoting effect of Nb on Ni/SiO2 in the hydrodeoxygenation of lignin derivatives to cycloalkanes†","authors":"Xiyue Lu , Hui Wang , Wei Liu , Mooeez ur Rehman , Lu Wang , Yan Xu , Shengnian Wang , Yujun Zhao","doi":"10.1039/d4cy01226g","DOIUrl":"10.1039/d4cy01226g","url":null,"abstract":"<div><div>Effective non-noble metal catalysts are critical for upgrading lignin-derived compounds into valuable products by hydrodeoxygenation (HDO). In this study, new Ni<sup>0</sup>–NiNbO<sub><em>x</em></sub>/SiO<sub>2</sub> catalysts were synthesized by combining sol–gel and impregnation methods. The HDO performance of these catalysts was then evaluated in the production of cycloalkanes from lignin-derived phenolic compounds. These Ni<sup>0</sup>–NiNbO<sub><em>x</em></sub>/SiO<sub>2</sub> catalysts present a considerably larger specific surface area than their Ni/SiO<sub>2</sub> counterparts. They work as bifunctional catalysts in the HDO process, where Ni<sup>0</sup> species act as active sites for hydrogenation while NiNbO<sub><em>x</em></sub> provides the Lewis acid sites necessary for deoxygenation. In this way, a significant improvement in the cyclohexane yield from 18% to 94.4% in guaiacol HDO was achieved on these Ni<sup>0</sup>–NiNbO<sub><em>x</em></sub>/SiO<sub>2</sub> catalysts. The best catalyst 10Ni/20Nb@SiO<sub>2</sub> exhibits complete conversion of guaiacol and almost 100% selectivity of cycloalkanes at 250 °C. The apparent activation energy for the 10Ni/20Nb@SiO<sub>2</sub> catalyst was identified to be 54.2 kJ mol<sup>−1</sup>, notably lower than that for other reported Ni-based catalysts. These findings highlight the superior performance of Ni<sup>0</sup>–NiNbO<sub><em>x</em></sub>/SiO<sub>2</sub> catalysts in the HDO of lignin-derived phenolic compounds, underscoring their great potential in producing cycloalkanes from renewable resources. Our efforts help pave the way for the catalytic transformation of lignin into valuable biofuels to advance the global mission toward a sustainable supply of fuels.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1134-1148"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430645","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}
Amol Agarwal , Yiqi Liu , Miyuki Hanazawa , Jiaqi Li , Takayuki Nakamuro , Eiichi Nakamura , Yosi Kratish , Tobin J. Marks
This study investigates the application of a novel third-row metal, tungsten, to carbon-supported single-site metal-oxo heterogeneous catalysis. Tungsten is a green and earth-abundant metal, but an unexplored candidate in this role. The carbon (AC = activated carbon)-supported tungsten dioxo complex, AC/WO2 was prepared via grafting of (DME)WO2Cl2 (DME = 1,2-dimethoxyethane) onto high-surface-area activated carbon. AC/WO2 was fully characterized by ICP-OES, XPS, EXAFS, XANES, SMART-EM, and DFT. W 4d7/2 XPS and W LIII-Edge XANES assign the oxidation state as W(vi), while EXAFS reveals two WO double and two W–O single bonds at distances of 1.73 and 1.92 Å, respectively. These data align well with DFT computational results, supporting the structure as Carbon(–μ-O–)2M(O)2. SMART-EM verifies that single W(vi) catalytic sites are bonded in an out-of-plane manner. The catalytic performance of air- and water-stable AC/WO2 is compared to that of AC/MoO2. AC/WO2 is more active and selective than the molybdenum analog in mediating alcohol dehydration of various substrates, and is recyclable. Notably, AC/WO2 is an effective and recyclable catalyst for primary aliphatic alcohol dehydration and forms no dehydrogenation side products in contrast to AC/MoO2. However, AC/WO2 is less effective in epoxidation and PET depolymerization. Overall, this work demonstrates the potential of carbon-supported third row metals for future studies.
{"title":"Tungsten-dioxo single-site heterogeneous catalyst on carbon: synthesis, structure, and catalysis†","authors":"Amol Agarwal , Yiqi Liu , Miyuki Hanazawa , Jiaqi Li , Takayuki Nakamuro , Eiichi Nakamura , Yosi Kratish , Tobin J. Marks","doi":"10.1039/d4cy01517g","DOIUrl":"10.1039/d4cy01517g","url":null,"abstract":"<div><div>This study investigates the application of a novel third-row metal, tungsten, to carbon-supported single-site metal-oxo heterogeneous catalysis. Tungsten is a green and earth-abundant metal, but an unexplored candidate in this role. The carbon (AC = activated carbon)-supported tungsten dioxo complex, AC/WO<sub>2</sub> was prepared <em>via</em> grafting of (DME)WO<sub>2</sub>Cl<sub>2</sub> (DME = 1,2-dimethoxyethane) onto high-surface-area activated carbon. AC/WO<sub>2</sub> was fully characterized by ICP-OES, XPS, EXAFS, XANES, SMART-EM, and DFT. W 4d<sub>7/2</sub> XPS and W L<sub>III</sub>-Edge XANES assign the oxidation state as W(<span>vi</span>), while EXAFS reveals two WO double and two W–O single bonds at distances of 1.73 and 1.92 Å, respectively. These data align well with DFT computational results, supporting the structure as Carbon(–μ-O–)<sub>2</sub>M(O)<sub>2</sub>. SMART-EM verifies that single W(<span>vi</span>) catalytic sites are bonded in an out-of-plane manner. The catalytic performance of air- and water-stable AC/WO<sub>2</sub> is compared to that of AC/MoO<sub>2</sub>. AC/WO<sub>2</sub> is more active and selective than the molybdenum analog in mediating alcohol dehydration of various substrates, and is recyclable. Notably, AC/WO<sub>2</sub> is an effective and recyclable catalyst for primary aliphatic alcohol dehydration and forms no dehydrogenation side products in contrast to AC/MoO<sub>2</sub>. However, AC/WO<sub>2</sub> is less effective in epoxidation and PET depolymerization. Overall, this work demonstrates the potential of carbon-supported third row metals for future studies.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1272-1279"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/cy/d4cy01517g?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430669","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}
Zhihui Li , Lanbo Liu , Wan Li , Xueqing Song , Zheng Wang , Longfei Li
Molecule activation theories are important in catalytic reactions, but sulfonyl activation remains unclear despite the fact that sulfonyl is a widely used leaving group in chemical synthesis. To unveil the nature of sulfonyl deactivation/activation by metal catalysts, the mechanisms of the competitive metal-catalyzed α-alkylation of sulfones and sulfonyl dissociation (Julia olefination) reactions are comprehensively investigated. A favorable metal-catalyzed mechanism is first proposed for the sulfonyl dissociation reaction. The sulfonyl dissociation and chemoselectivity are revealed to originate from hydride addition into the CC bond of the vinyl sulfone intermediate. Through natural localized molecular orbital analysis, a sulfonyl deactivation model with a πC(α)C(β) → σ*S–O hyperconjugation effect and a sulfonyl activation model with πC(α)C(β) → π*Ph conjugation effect are proposed. Guided by the sulfonyl activation model, switchable chemoselectivity strategies are provided to control these reactions.
{"title":"Nature of sulfonyl deactivation/activation by metal catalysts†","authors":"Zhihui Li , Lanbo Liu , Wan Li , Xueqing Song , Zheng Wang , Longfei Li","doi":"10.1039/d4cy01350f","DOIUrl":"10.1039/d4cy01350f","url":null,"abstract":"<div><div>Molecule activation theories are important in catalytic reactions, but sulfonyl activation remains unclear despite the fact that sulfonyl is a widely used leaving group in chemical synthesis. To unveil the nature of sulfonyl deactivation/activation by metal catalysts, the mechanisms of the competitive metal-catalyzed α-alkylation of sulfones and sulfonyl dissociation (Julia olefination) reactions are comprehensively investigated. A favorable metal-catalyzed mechanism is first proposed for the sulfonyl dissociation reaction. The sulfonyl dissociation and chemoselectivity are revealed to originate from hydride addition into the CC bond of the vinyl sulfone intermediate. Through natural localized molecular orbital analysis, a sulfonyl deactivation model with a π<sub>C(α)C(β)</sub> → σ*<sub>S–O</sub> hyperconjugation effect and a sulfonyl activation model with π<sub>C(α)C(β)</sub> → π*<sub>Ph</sub> conjugation effect are proposed. Guided by the sulfonyl activation model, switchable chemoselectivity strategies are provided to control these reactions.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1016-1027"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430623","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}
Daniel Dittmann , Alime Ileri , Dennis Strassheim , Michael Dyballa
The amount of BTEX aromatics obtained from the conversion of ethanol (ETA) is increased by combining ZSM-5 catalysts having optimum acidity with desilication and zinc ion exchange. Zinc leads to preferred dehydrogenation instead of hydrogen transfer. It decreases the share of paraffin products and increases BTEX contents (up to SBTEX = 50%) at the cost of lifetime. The latter can be increased via desilication. An ethylene feed increases lifetime and BTEX production as result of oxygenate absence. Combination of improvements resulted in a C2 conversion capacity of 206 g g−1 and a total yield of BTEX aromatics of 31.6 g g−1, which is about a factor of 2–3 times better than the respective values found for microporous, mesoporous, or microporous Zn-exchanged materials. In situ UV/vis spectra reveal that desilicated samples coke significantly slower than microporous samples, whereas Zn exchange supports the formation of coke. Thus, by a clever combination of suitable post-modifications, a significantly higher BTEX production from the primary source ethanol can be achieved.
{"title":"Higher BTEX aromatic yield from ethanol over desilicated H,Zn-[Al]ZSM-5 catalysts†","authors":"Daniel Dittmann , Alime Ileri , Dennis Strassheim , Michael Dyballa","doi":"10.1039/d4cy01062k","DOIUrl":"10.1039/d4cy01062k","url":null,"abstract":"<div><div>The amount of BTEX aromatics obtained from the conversion of ethanol (ETA) is increased by combining ZSM-5 catalysts having optimum acidity with desilication and zinc ion exchange. Zinc leads to preferred dehydrogenation instead of hydrogen transfer. It decreases the share of paraffin products and increases BTEX contents (up to <em>S</em><sub>BTEX</sub> = 50%) at the cost of lifetime. The latter can be increased <em>via</em> desilication. An ethylene feed increases lifetime and BTEX production as result of oxygenate absence. Combination of improvements resulted in a C<sub>2</sub> conversion capacity of 206 g g<sup>−1</sup> and a total yield of BTEX aromatics of 31.6 g g<sup>−1</sup>, which is about a factor of 2–3 times better than the respective values found for microporous, mesoporous, or microporous Zn-exchanged materials. <em>In situ</em> UV/vis spectra reveal that desilicated samples coke significantly slower than microporous samples, whereas Zn exchange supports the formation of coke. Thus, by a clever combination of suitable post-modifications, a significantly higher BTEX production from the primary source ethanol can be achieved.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1028-1040"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/cy/d4cy01062k?page=search","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430624","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 selective hydrogenation of phenylacetylene plays an important role in purifying the styrene monomer. Non-noble Ni3Cu–Sn trimetallic catalysts have demonstrated high styrene selectivity at an acceptable reaction rate in phenylacetylene hydrogenation. However, the synergistic mechanism of Ni, Cu, and Sn in complex Ni–Cu–Sn alloys remains unclear, restricting the design and development of more efficient trimetallic catalysts. Herein, we explore the interactions among the three metals by employing relatively simple Ni3Cu(1−y)Sny pseudo-binary alloys, based on the similarity in crystal structure between Ni3CuSnx/SBA-15 and Ni3Cu(1−y)Sny/SBA-15 catalysts. Density functional theory calculations reveal that Ni and Cu atoms directly contribute to the adsorption of phenylacetylene, styrene and hydrogen at trimer sites, while Sn atoms modulate the electronic and geometric properties of Ni. As the degree of Cu substitution by Sn in cubic Ni3Cu(1−y)Sny planes increases, the Ni–Ni bond lengthens and Ni atoms become more electron-rich, thereby weakening styrene adsorption. Nevertheless, more Sn substitution induces a cubic-to-hexagonal crystal structure transformation, leading to an adverse effect. This trend is supported by experimental results: styrene selectivity on Ni3Cu(1−y)Sny/SBA-15 increases with y up to 0.5, but decreases with further Sn substitution due to the crystal structure transformation. The hydrogenation activity of the catalysts consistently deceases with increasing y, likely owing to a reduction in the concentration of Ni trimers, which serve as the primary adsorption sites for reactants. Therefore, the key to achieving high styrene selectivity is increasing the degree of Cu substitution by Sn in Ni3Cu–Sn catalysts until the cubic-to-hexagonal transformation occurs.
{"title":"Unraveling the synergistic mechanism of multimetals in Ni3Cu–Sn catalysts for selective hydrogenation of phenylacetylene†","authors":"Aohui Xiao , Kehang Ruan , Yuqi Zhou , Hongjie Cui , Zhiming Zhou","doi":"10.1039/d4cy01464b","DOIUrl":"10.1039/d4cy01464b","url":null,"abstract":"<div><div>The selective hydrogenation of phenylacetylene plays an important role in purifying the styrene monomer. Non-noble Ni<sub>3</sub>Cu–Sn trimetallic catalysts have demonstrated high styrene selectivity at an acceptable reaction rate in phenylacetylene hydrogenation. However, the synergistic mechanism of Ni, Cu, and Sn in complex Ni–Cu–Sn alloys remains unclear, restricting the design and development of more efficient trimetallic catalysts. Herein, we explore the interactions among the three metals by employing relatively simple Ni<sub>3</sub>Cu<sub>(1−<em>y</em>)</sub>Sn<sub><em>y</em></sub> pseudo-binary alloys, based on the similarity in crystal structure between Ni<sub>3</sub>CuSn<sub><em>x</em></sub>/SBA-15 and Ni<sub>3</sub>Cu<sub>(1−<em>y</em>)</sub>Sn<sub><em>y</em></sub>/SBA-15 catalysts. Density functional theory calculations reveal that Ni and Cu atoms directly contribute to the adsorption of phenylacetylene, styrene and hydrogen at trimer sites, while Sn atoms modulate the electronic and geometric properties of Ni. As the degree of Cu substitution by Sn in cubic Ni<sub>3</sub>Cu<sub>(1−<em>y</em>)</sub>Sn<sub><em>y</em></sub> planes increases, the Ni–Ni bond lengthens and Ni atoms become more electron-rich, thereby weakening styrene adsorption. Nevertheless, more Sn substitution induces a cubic-to-hexagonal crystal structure transformation, leading to an adverse effect. This trend is supported by experimental results: styrene selectivity on Ni<sub>3</sub>Cu<sub>(1−<em>y</em>)</sub>Sn<sub><em>y</em></sub>/SBA-15 increases with <em>y</em> up to 0.5, but decreases with further Sn substitution due to the crystal structure transformation. The hydrogenation activity of the catalysts consistently deceases with increasing <em>y</em>, likely owing to a reduction in the concentration of Ni trimers, which serve as the primary adsorption sites for reactants. Therefore, the key to achieving high styrene selectivity is increasing the degree of Cu substitution by Sn in Ni<sub>3</sub>Cu–Sn catalysts until the cubic-to-hexagonal transformation occurs.</div></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":"15 4","pages":"Pages 1203-1216"},"PeriodicalIF":4.4,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430650","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号