Pub Date : 2025-04-04DOI: 10.1016/j.mcat.2025.115083
Biqin Wang, Xiaohan Yang, Yahong Li
Twelve cationic cyclometalated iridium(III) complexes with the general formula [Ir(C^N)2(N^N)]PF6 (Ir1-Ir12), where C^N are cyclometalated ligands, including 2-(2,4-difluorophenyl)pyridine (dfppy), 2-(4-(trifluoromethyl)phenyl) pyridine (CF3ppy), and 1-(4-(trifluoromethyl)phenyl)isoquinoline (CF3piq) and where N^N represents 3-(pyridin-2-yl)imidazo[1,5-a]pyridine-based ancillary ligands, were successfully synthesized and structurally characterized via NMR and X-ray diffraction. The targets of this work were to investigate the effects of changes in the C^N and N^N ligands of the iridium(III) complexes on their photophysical, electrochemical, and catalytic properties. DFT and TD-DFT calculations were also utilized to support the photophysical and electrochemical property studies. The intense green to orange-red emissions of Ir1-Ir12 arose from the 3ILCT/3LLCT/3MLCT transition in the spectral range between 498 and 603 nm, with excited-state lifetimes between 4.61 and 7.45 μs. These complexes were used as photocatalysts for the [4 + 2] cycloaddition of maleimides and N,N-dimethylanilines. Complex Ir7 showed excellent catalytic activity, affording products in moderate to high yields (42 %-92 %) from a wide range of substrates under mild conditions.
{"title":"Synthesis, properties and photocatalytic activities of iridium(Ⅲ) complexes based on the derivatives of imidazo[1,5-a]pyridine with electron-withdrawing groups","authors":"Biqin Wang, Xiaohan Yang, Yahong Li","doi":"10.1016/j.mcat.2025.115083","DOIUrl":"10.1016/j.mcat.2025.115083","url":null,"abstract":"<div><div>Twelve cationic cyclometalated iridium(III) complexes with the general formula [Ir(C^N)<sub>2</sub>(N^N)]PF<sub>6</sub> (<strong>Ir1</strong>-<strong>Ir12</strong>), where C^N are cyclometalated ligands, including 2-(2,4-difluorophenyl)pyridine (dfppy), 2-(4-(trifluoromethyl)phenyl) pyridine (CF<sub>3</sub>ppy), and 1-(4-(trifluoromethyl)phenyl)isoquinoline (CF<sub>3</sub>piq) and where N^N represents 3-(pyridin-2-yl)imidazo[1,5-a]pyridine-based ancillary ligands, were successfully synthesized and structurally characterized via NMR and X-ray diffraction. The targets of this work were to investigate the effects of changes in the C^N and N^N ligands of the iridium(III) complexes on their photophysical, electrochemical, and catalytic properties. DFT and TD-DFT calculations were also utilized to support the photophysical and electrochemical property studies. The intense green to orange-red emissions of <strong>Ir1</strong>-<strong>Ir12</strong> arose from the <sup>3</sup>ILCT/<sup>3</sup>LLCT/<sup>3</sup>MLCT transition in the spectral range between 498 and 603 nm, with excited-state lifetimes between 4.61 and 7.45 <em>μ</em>s. These complexes were used as photocatalysts for the [4 + 2] cycloaddition of maleimides and <em>N,N</em>-dimethylanilines. Complex <strong>Ir7</strong> showed excellent catalytic activity, affording products in moderate to high yields (42 %-92 %) from a wide range of substrates under mild conditions.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115083"},"PeriodicalIF":3.9,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767595","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 : 2025-04-04DOI: 10.1016/j.mcat.2025.115095
Zeyu Yang , Qianqian Qi , Mingyu Fan , Yafei Wang , Li Tong
The Co3O4 catalysts with different precursors (Na2CO3, CH4N2O) were synthesized and evaluated for its o-xylene catalytic oxidation performance. A series of techniques including BET, XRD, TEM, XPS, H2-TPR were employed to characterize the physical and chemical properties of catalysts under various preparation conditions. The results indicated that physisorption played an important role in the o-xylene removal and higher calcination temperature destructed the specific surface areas of the Co3O4 samples. The enhanced catalytic performance of Co3O4N catalyst was mainly attributed to be abundance in active Co3+ and lattice oxygen species, while that of Co3O4C catalyst was ascribed to the formation of superoxide anion, especially the lower calcination temperature facilitated the generation of active species. In addition, the reaction mechanisms toward o-xylene oxidation over Co3O4 catalysts obtained by different preparation methods were explored in detail. The o-xylene molecule preferentially adsorbed onto the Co3+ ion sites, and was further oxidized by the lattice oxygen or superoxide anion with the product being o-methyl benzyl alcohol. Soon the benzyl alcohol was transformed into the o-methyl benzaldehyde, and afterward to form benzoic acid. Later, the benzoic acid was converted into small-molecule carboxylate for Co3O4N catalyst, whereas for Co3O4C catalysts, the benzoic acid was further turned into maleic acid subsequently into acetone. Finally, both the small-molecule carboxylate and acetone species were oxidized to CO2 and H2O. This finding offers some valuable insights for designing efficient o-xylene oxidation catalysts and mitigating industrial air pollution.
{"title":"Effects of the preparation methods of Co3O4 catalysts on catalytic oxidization performance toward o-xylene","authors":"Zeyu Yang , Qianqian Qi , Mingyu Fan , Yafei Wang , Li Tong","doi":"10.1016/j.mcat.2025.115095","DOIUrl":"10.1016/j.mcat.2025.115095","url":null,"abstract":"<div><div>The Co<sub>3</sub>O<sub>4</sub> catalysts with different precursors (Na<sub>2</sub>CO<sub>3</sub>, CH<sub>4</sub>N<sub>2</sub>O) were synthesized and evaluated for its o-xylene catalytic oxidation performance. A series of techniques including BET, XRD, TEM, XPS, H<sub>2</sub>-TPR were employed to characterize the physical and chemical properties of catalysts under various preparation conditions. The results indicated that physisorption played an important role in the o-xylene removal and higher calcination temperature destructed the specific surface areas of the Co<sub>3</sub>O<sub>4</sub> samples. The enhanced catalytic performance of Co<sub>3</sub>O<sub>4</sub><sub><img></sub>N catalyst was mainly attributed to be abundance in active Co<sup>3+</sup> and lattice oxygen species, while that of Co<sub>3</sub>O<sub>4</sub><sub><img></sub>C catalyst was ascribed to the formation of superoxide anion, especially the lower calcination temperature facilitated the generation of active species. In addition, the reaction mechanisms toward o-xylene oxidation over Co<sub>3</sub>O<sub>4</sub> catalysts obtained by different preparation methods were explored in detail. The o-xylene molecule preferentially adsorbed onto the Co<sup>3+</sup> ion sites, and was further oxidized by the lattice oxygen or superoxide anion with the product being o-methyl benzyl alcohol. Soon the benzyl alcohol was transformed into the o-methyl benzaldehyde, and afterward to form benzoic acid. Later, the benzoic acid was converted into small-molecule carboxylate for Co<sub>3</sub>O<sub>4</sub><sub><img></sub>N catalyst, whereas for Co<sub>3</sub>O<sub>4</sub><sub><img></sub>C catalysts, the benzoic acid was further turned into maleic acid subsequently into acetone. Finally, both the small-molecule carboxylate and acetone species were oxidized to CO<sub>2</sub> and H<sub>2</sub>O. This finding offers some valuable insights for designing efficient o-xylene oxidation catalysts and mitigating industrial air pollution.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115095"},"PeriodicalIF":3.9,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767598","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 : 2025-04-04DOI: 10.1016/j.mcat.2025.115090
Chunnian Xia , Xinyi Wu , Bingyang Wang , Han Zhang , Kailin Chen , Nuoqi Jin , Qiangsheng Sun , Wei Sun
In this study, a series of Mg(II) complexes supported by aminopyridine-N4 (MEP, DAP, TPA) and TMC (14-TMC) ligands were synthesized and characterized using various spectroscopic techniques. These Mg(II) complexes were investigated the catalytic activity for the cycloaddition of carbon dioxide with epoxides to obtain cyclic carbonates under cocatalyst- and solvent-free conditions, providing moderate to excellent yields depending on the specific N4 ligands used. The study involved analyzing the spectroscopic characterizations and experimental results to discuss the possible ligand topological structures of Mg-N4 complexes and their impact on catalytic performance. Moreover, the addition of (triphenylphosphoranylidene)ammonium chloride (PPNCl) as a cocatalyst significantly enhanced the turnover frequency (TOF) to 2100 h-1 for the Mg-1 [MEP-Mg(II), 0.01 mol % catalyst loading]. Also, the Mg-1 catalyst demonstrates excellent stability under the reaction conditions, allowing for multiple reuses.
{"title":"Efficient fixation of CO2 with epoxides catalyzed by Mg(II)-N4 complexes","authors":"Chunnian Xia , Xinyi Wu , Bingyang Wang , Han Zhang , Kailin Chen , Nuoqi Jin , Qiangsheng Sun , Wei Sun","doi":"10.1016/j.mcat.2025.115090","DOIUrl":"10.1016/j.mcat.2025.115090","url":null,"abstract":"<div><div>In this study, a series of Mg(II) complexes supported by aminopyridine-N4 (MEP, DAP, TPA) and TMC (14-TMC) ligands were synthesized and characterized using various spectroscopic techniques. These Mg(II) complexes were investigated the catalytic activity for the cycloaddition of carbon dioxide with epoxides to obtain cyclic carbonates under cocatalyst- and solvent-free conditions, providing moderate to excellent yields depending on the specific N4 ligands used. The study involved analyzing the spectroscopic characterizations and experimental results to discuss the possible ligand topological structures of Mg-N4 complexes and their impact on catalytic performance. Moreover, the addition of (triphenylphosphoranylidene)ammonium chloride (PPNCl) as a cocatalyst significantly enhanced the turnover frequency (TOF) to 2100 h<sup>-1</sup> for the <strong>Mg-1</strong> [MEP-Mg(II), 0.01 mol % catalyst loading]. Also, the <strong>Mg-1</strong> catalyst demonstrates excellent stability under the reaction conditions, allowing for multiple reuses.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115090"},"PeriodicalIF":3.9,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767594","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 : 2025-04-03DOI: 10.1016/j.mcat.2025.115088
Jianhua Liu, Gelan Wang, Chen Chen, Xiangrong Zhou, Peihe Li
The photocatalytic reductive coupling of carbon-carbon bonds via pinacol coupling represents a significant transformation in organic synthesis chemistry. Several elegant studies have reported the use of metal or organic photocatalysts in this process, but these often lead to trace metal residues or involve intricate operational procedures. Herein, we report a photoinduced pinacol coupling of carbon-carbon bonds from ketones, achieved under photocatalyst-free conditions using triethoxysilane or Hantzsch ester as the reductant. In the model reaction employing benzophenone as substrate and triethoxysilane as the reductant, the corresponding pinacol product was obtained in 96 % yield under 370 nm LED light irradiation. Similarly, when Hantzsch ester served as the reductant, the pinacol product was obtained in 95 % yield under 423 nm LED light irradiation. The substrate scope demonstrated that six substrates yielded the corresponding products with yields ranging from 40 % to 96 %. Notably, when acetophenone, a substrate with minimal steric hindrance, was used under the established conditions, only 1-phenylethanol was produced. This work introduces two practical methods for the synthesis of carbon-carbon coupling intermediates through pinacol coupling of benzophenone-derived substrates, positioning these methodologies as promising candidates for various applications.
{"title":"Photoinduced pinacol coupling of carbon-carbon bonds via triethoxysilane or Hantzsch Ester","authors":"Jianhua Liu, Gelan Wang, Chen Chen, Xiangrong Zhou, Peihe Li","doi":"10.1016/j.mcat.2025.115088","DOIUrl":"10.1016/j.mcat.2025.115088","url":null,"abstract":"<div><div>The photocatalytic reductive coupling of carbon-carbon bonds via pinacol coupling represents a significant transformation in organic synthesis chemistry. Several elegant studies have reported the use of metal or organic photocatalysts in this process, but these often lead to trace metal residues or involve intricate operational procedures. Herein, we report a photoinduced pinacol coupling of carbon-carbon bonds from ketones, achieved under photocatalyst-free conditions using triethoxysilane or Hantzsch ester as the reductant. In the model reaction employing benzophenone as substrate and triethoxysilane as the reductant, the corresponding pinacol product was obtained in 96 % yield under 370 nm LED light irradiation. Similarly, when Hantzsch ester served as the reductant, the pinacol product was obtained in 95 % yield under 423 nm LED light irradiation. The substrate scope demonstrated that six substrates yielded the corresponding products with yields ranging from 40 % to 96 %. Notably, when acetophenone, a substrate with minimal steric hindrance, was used under the established conditions, only 1-phenylethanol was produced. This work introduces two practical methods for the synthesis of carbon-carbon coupling intermediates through pinacol coupling of benzophenone-derived substrates, positioning these methodologies as promising candidates for various applications.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115088"},"PeriodicalIF":3.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760052","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 : 2025-04-03DOI: 10.1016/j.mcat.2025.115092
Songquan Tang , Wenzhi Li , Jingting Jin , Xin Zhang , Zilong Shen , Yunfan Gui
Catalytic combustion of lean methane is an effective measure to alleviate the greenhouse effect, which posing extensive demands for catalysts with appreciable reactivity and thermal stability. Herein, the reactivity and thermal stability of Pd/ZSM-5 catalysts prepared by ammonia evaporation and impregnation were tested. Experimental results indicated that the catalyst prepared by the ammonia evaporation method exhibited higher catalytic activity than that prepared by the impregnation method with similar Pd loadings. Especially, when the palladium loading is 0.1 %, the methane conversion of Pd/ZSM-5 prepared by AE method maintained at 80 % for 12 h at 550 °C while the methane conversion of Pd/ZSM-5 prepared by IM method decreased from 70 % to 20 % within 12 h at 550 °C. Through characterization, it was found that the elevated reactivity originated from the high dispersion of palladium due to the boosted interaction between palladium species and ZSM-5 support. These findings on the preparation of Pd catalysts via ammonia evaporation offer a practical reference for catalyst preparation environment adjustment, active species anchoring, and support-metal interactions, thus providing a promising blueprint for the design of future methane catalytic combustion materials.
{"title":"Lean methane catalytic combustion using Pd/ZSM-5 catalysts prepared by ammonia evaporation method","authors":"Songquan Tang , Wenzhi Li , Jingting Jin , Xin Zhang , Zilong Shen , Yunfan Gui","doi":"10.1016/j.mcat.2025.115092","DOIUrl":"10.1016/j.mcat.2025.115092","url":null,"abstract":"<div><div>Catalytic combustion of lean methane is an effective measure to alleviate the greenhouse effect, which posing extensive demands for catalysts with appreciable reactivity and thermal stability. Herein, the reactivity and thermal stability of Pd/ZSM-5 catalysts prepared by ammonia evaporation and impregnation were tested. Experimental results indicated that the catalyst prepared by the ammonia evaporation method exhibited higher catalytic activity than that prepared by the impregnation method with similar Pd loadings. Especially, when the palladium loading is 0.1 %, the methane conversion of Pd/ZSM-5 prepared by AE method maintained at 80 % for 12 h at 550 °C while the methane conversion of Pd/ZSM-5 prepared by IM method decreased from 70 % to 20 % within 12 h at 550 °C. Through characterization, it was found that the elevated reactivity originated from the high dispersion of palladium due to the boosted interaction between palladium species and ZSM-5 support. These findings on the preparation of Pd catalysts <em>via</em> ammonia evaporation offer a practical reference for catalyst preparation environment adjustment, active species anchoring, and support-metal interactions, thus providing a promising blueprint for the design of future methane catalytic combustion materials.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115092"},"PeriodicalIF":3.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760050","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 : 2025-04-03DOI: 10.1016/j.mcat.2025.115084
Qiang Guo , Yixiao Wu , Yongjun Liu , Shiqi Tao , Xiaoshuang Wang , Wei Huang
Directly convert CH4 and CO2 into acetic acid is a 100 % atomic efficiency reaction, but remains a great challenge under mild conditions. Herein, we report that acetic acid is generated as the sole liquid product by direct CH4 and CO2 coupling over Pd/LDH catalyst by two stepwise technique at 200 °C and atmospheric pressure. The formation of acetic acid is closely related to the surface Pd0 content, as well as the number of medium-strong acid and medium-strong base on the catalyst surface. The results of in-situ DRIFTS experiments show that acetic acid is mainly formed by the coupling of CH3* and CO2* (CH3*+CO2*→CH3COO*+*), or via CHx* and COOH* coupling (CHx*+COOH*→CHxCOOH*+*) to form acetate which then followed by hydrogenation reaction. In which CH3* is originated from CH4 dehydrogenation step, and COOH* may be formed by the reduction of CO2 on metallic Pd sites. This study provides a feasible approach for the construction of high selectivity catalytic materials for the direct co-conversion of CH4 and CO2 into acetic acid at low temperature.
{"title":"Direct coupling of CH4 and CO2 to acetic acid over Pd/LDH catalyst by stepwise technique","authors":"Qiang Guo , Yixiao Wu , Yongjun Liu , Shiqi Tao , Xiaoshuang Wang , Wei Huang","doi":"10.1016/j.mcat.2025.115084","DOIUrl":"10.1016/j.mcat.2025.115084","url":null,"abstract":"<div><div>Directly convert CH<sub>4</sub> and CO<sub>2</sub> into acetic acid is a 100 % atomic efficiency reaction, but remains a great challenge under mild conditions. Herein, we report that acetic acid is generated as the sole liquid product by direct CH<sub>4</sub> and CO<sub>2</sub> coupling over Pd/LDH catalyst by two stepwise technique at 200 °C and atmospheric pressure. The formation of acetic acid is closely related to the surface Pd<sup>0</sup> content, as well as the number of medium-strong acid and medium-strong base on the catalyst surface. The results of <em>in-situ</em> DRIFTS experiments show that acetic acid is mainly formed by the coupling of CH<sub>3</sub>* and CO<sub>2</sub>* (CH<sub>3</sub>*+CO<sub>2</sub>*→CH<sub>3</sub>COO*+*), or via CH<em><sub>x</sub></em>* and COOH* coupling (CH<em><sub>x</sub></em>*+COOH*→CH<em><sub>x</sub></em>COOH*+*) to form acetate which then followed by hydrogenation reaction. In which CH<sub>3</sub>* is originated from CH<sub>4</sub> dehydrogenation step, and COOH* may be formed by the reduction of CO<sub>2</sub> on metallic Pd sites. This study provides a feasible approach for the construction of high selectivity catalytic materials for the direct co-conversion of CH<sub>4</sub> and CO<sub>2</sub> into acetic acid at low temperature.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115084"},"PeriodicalIF":3.9,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760053","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 : 2025-04-02DOI: 10.1016/j.mcat.2025.115076
Dejiang Zheng, Lu Li, Shitao Yu
Economical and sulphur-free Ni catalysts are attractive alternatives to hydrodeoxygenation (HDO) of fats and oils for the production of diesel-range paraffins, but are prone to decarbonylation/decarboxylation (DCOx) reactions. Metal oxide decorated nickel catalysts exhibit remarkably high catalytic activity, which can modify the nickel catalyzed deoxygenation reaction pathway. Herein, a series of NiMo@SAPO-11 catalysts with different Ni/Mo mass ratio were prepared using an in-situ synthesis under mild conditions (100 °C, 12 h). The as-synthesized bimetallic NiMo nanocatalyst with a Ni/Mo mass ratio of 3:1 showed an excellent catalytic HDO activity with 100 % conversion of triolein and 86.5 % selectivity of octadecane. Combined with experimental results and density functional calculations, it was demonstrated that oxygen vacancies derived from MoOx considerably favored the adsorption and activation of substrates. An efficient selective HDO process for fats and oils has been achieved by direct deoxygenation of hydroxyl/carbonyl functional groups.
{"title":"In-situ synthesis of NiMo@SAPO-11 under mild conditions for the hydrodeoxygenation of triolein","authors":"Dejiang Zheng, Lu Li, Shitao Yu","doi":"10.1016/j.mcat.2025.115076","DOIUrl":"10.1016/j.mcat.2025.115076","url":null,"abstract":"<div><div>Economical and sulphur-free Ni catalysts are attractive alternatives to hydrodeoxygenation (HDO) of fats and oils for the production of diesel-range paraffins, but are prone to decarbonylation/decarboxylation (DCO<sub>x</sub>) reactions. Metal oxide decorated nickel catalysts exhibit remarkably high catalytic activity, which can modify the nickel catalyzed deoxygenation reaction pathway. Herein, a series of NiMo@SAPO-11 catalysts with different Ni/Mo mass ratio were prepared using an <em>in-situ</em> synthesis under mild conditions (100 °C, 12 h). The as-synthesized bimetallic NiMo nanocatalyst with a Ni/Mo mass ratio of 3:1 showed an excellent catalytic HDO activity with 100 % conversion of triolein and 86.5 % selectivity of octadecane. Combined with experimental results and density functional calculations, it was demonstrated that oxygen vacancies derived from MoO<sub>x</sub> considerably favored the adsorption and activation of substrates. An efficient selective HDO process for fats and oils has been achieved by direct deoxygenation of hydroxyl/carbonyl functional groups.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115076"},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746395","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 : 2025-04-02DOI: 10.1016/j.mcat.2025.115081
Shaoshuai Zhu , Binhao Wang , Guochao Xu, Ye Ni
l-pipecolic acid (l-PA) is an essential chiral intermediate for local anesthetics and macrolide antibiotics. To achieve more stable and cost-effective biosynthesis of l-PA from l-lysine (l-Lys), a cascade enzymatic pathway with self-sufficient cofactor recycling was developed, incorporating lysine-6-dehydrogenase (LysDH) and pyrroline-5-carboxylate reductase (P5CR). To overcome bottlenecks in the pathway, Ec-P5CR from Enterococcus casseliflavus was identified as a promising biocatalyst for enhancing l-PA production. For further improvement of l-PA yield, protein engineering was performed on Ec-P5CR. The resulting variant K261W, combined with Rp-LysDH from Rhodobacter pomeroyi DSS-3, achieved significantly enhanced yield of 93 % at 100 mM l-Lys, as well as an impressive yield of 83 % at 500 mM l-Lys. MD simulations revealed that improved hydride transfer efficiency was mainly responsible for the enhanced performance of K261W, leading to shorter distances between catalytic residues and substrates. This work paves the way for efficient and sustainable l-PA synthesis, showcasing the potential of enzyme optimization in industrial applications.
{"title":"Mining and engineering of pyrroline-5-carboxylate reductase for biocatalytic production of l-pipecolic acid with self-sufficient cofactor recycling","authors":"Shaoshuai Zhu , Binhao Wang , Guochao Xu, Ye Ni","doi":"10.1016/j.mcat.2025.115081","DOIUrl":"10.1016/j.mcat.2025.115081","url":null,"abstract":"<div><div><span>l</span>-pipecolic acid (<span>l</span>-PA) is an essential chiral intermediate for local anesthetics and macrolide antibiotics. To achieve more stable and cost-effective biosynthesis of <span>l</span>-PA from <span>l</span>-lysine (<span>l</span>-Lys), a cascade enzymatic pathway with self-sufficient cofactor recycling was developed, incorporating lysine-6-dehydrogenase (LysDH) and pyrroline-5-carboxylate reductase (P5CR). To overcome bottlenecks in the pathway, Ec-P5CR from <em>Enterococcus casseliflavus</em> was identified as a promising biocatalyst for enhancing <span>l</span>-PA production. For further improvement of <span>l</span>-PA yield, protein engineering was performed on Ec-P5CR. The resulting variant K261W, combined with Rp-LysDH from <em>Rhodobacter pomeroyi</em> DSS-3, achieved significantly enhanced yield of 93 % at 100 mM <span>l</span>-Lys, as well as an impressive yield of 83 % at 500 mM <span>l</span>-Lys. MD simulations revealed that improved hydride transfer efficiency was mainly responsible for the enhanced performance of K261W, leading to shorter distances between catalytic residues and substrates. This work paves the way for efficient and sustainable <span>l</span>-PA synthesis, showcasing the potential of enzyme optimization in industrial applications.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115081"},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746394","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}
Direct oxidation of methane to methanol utilizing molecular oxygen is an important yet challenging process. In this research, we report supporting Au nanoparticles on the surface of H-beta, which acts as the catalyst for oxidation of methane using molecular oxygen as the oxidant without co-reductants. This catalytic process resulted in the high-yield production of methanol, acetic acid, and formic acid as the major products. Furthermore, mechanism study indicated that the surface hydroxyl species or oxygen species on Au nanoparticle might be crucial for generating the active species for the reaction.
{"title":"Methane selective oxidation by Au nanoparticles supported on BETA zeolites using O2 as the oxidant","authors":"Ruoyan Wang, Qianqian Zhu, Zhuoyuan Chen, Wei Wang, Yanshuo Li, Zhenxin Zhang","doi":"10.1016/j.mcat.2025.115091","DOIUrl":"10.1016/j.mcat.2025.115091","url":null,"abstract":"<div><div>Direct oxidation of methane to methanol utilizing molecular oxygen is an important yet challenging process. In this research, we report supporting Au nanoparticles on the surface of H-beta, which acts as the catalyst for oxidation of methane using molecular oxygen as the oxidant without co-reductants. This catalytic process resulted in the high-yield production of methanol, acetic acid, and formic acid as the major products. Furthermore, mechanism study indicated that the surface hydroxyl species or oxygen species on Au nanoparticle might be crucial for generating the active species for the reaction.</div></div>","PeriodicalId":393,"journal":{"name":"Molecular Catalysis","volume":"579 ","pages":"Article 115091"},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746939","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 : 2025-04-02DOI: 10.1016/j.mcat.2025.115089
Lu Ren , Bin Wang , Yueli Wen , Maohong Fan , Zhaoxiong Huang , Wenxuan Li , Wei Huang , Jing Li , Jianping Guo
Acid-base synergistic effect is crucial in adjusting the catalytic performance of CO2 hydrogenation to methanol, an efficient CO2 emission reduction and carbon recycle strategy. Two MOFs-derived catalysts (CZ-MIL, CA-ZIF) with opposite acid-base properties were tailored by using MIL-68 (Al) and ZIF-8 (Zn) as precursors, and the above two MOFs precursors were hybridized (C-ZAx) to control the acid-base property of the catalyst. C-ZA0.6 (molar ratio of MIL-68 (Al) to ZIF-8 (Zn)=0.6) exhibits a promising catalytic performance with CO2 conversion of 8.9 %, methanol selectivity of 61.85 %, and STY of 117.02 mg mL−1·h−1 at 4 MPa and 523 K. Combined with comprehensive analysis, it is found that methanol selectivity is closely related to weak acid sites arising from the residual skeleton of MIL-68. Acid-base synergy facilitates the hydrogenation of CO2 to methanol. The basic sites are responsible for adsorbing and activating CO2, and the acidic site helps to stabilize CO* and facilitate the further hydrogenation to methanol. This work provides a new idea and feasible method for enhancing the catalytic performance of CO2 hydrogenation to methanol.
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