K. Sale, B. Simmons, Paul D. Adams, S. Singer, T. Northen, K. Deng, Le Thanh Mai Pham
Lignin is the most abundant renewable source of aromatics on earth, and conversion of it to chemicals and fuels is needed to build an economically viable renewable biofuels industry. Biological routes to converting lignin to fuels and chemicals involve depolymerizing lignin using lignin-degrading enzymes that catalyze the breaking of ether and carbon-carbon bonds in the phenolic and non-phenolic subunits of lignin. Laccases are a crucial class of lignin-degrading enzymes and are copper-containing enzymes capable of oxidizing electron-rich organic substrates such as lignin using molecular oxygen as an electron acceptor. The genome of Cerrena unicolor was recently added to the JGI MycoCosm database and has eight laccases. Two of these laccases, designated Lc1 and Lc2, predicted to have the highest likelihood for successful expression in soluble, active form were selected for characterization. Lc1 and Lc2, which share 65% sequence identity, were heterologously expressed in Komagataella pastoris (formerly Pichia pastoris), allowing characterization and comparison of their purified forms. Lc1 and Lc2 had half-lives of 16 min and 185 min at 60°C, respectively, and, based on molecular dynamics simulations, the longer half-life of Lc2 was due to an increased number and persistence of salt bridges compared to Lc1. Using model lignin-like dimers and a nanostructure-initiator mass spectrometry assay to quantify catalysis of specific bond-breaking events, both Lc1 and Lc2 had their highest activity at pH 3 and in combination with syringaldehyde as a mediator, with Lc1 having a higher catalytic efficiency of β-O-4' ether and C-C bond breaking. This comparative study demonstrates the diversity, including thermostability differences, of laccases from the same fungus, and improves our understanding of laccase catalyzed breaking of bonds commonly found in lignin, which will facilitate the developing this important class of enzymes for applications in the conversion of lignin to valuable bioproducts.
{"title":"Heterologous Expression, Characterization, and Comparison of Laccases from the White Rot Causing Basidiomycete Cerrena Unicolor","authors":"K. Sale, B. Simmons, Paul D. Adams, S. Singer, T. Northen, K. Deng, Le Thanh Mai Pham","doi":"10.21926/cr.2203028","DOIUrl":"https://doi.org/10.21926/cr.2203028","url":null,"abstract":"Lignin is the most abundant renewable source of aromatics on earth, and conversion of it to chemicals and fuels is needed to build an economically viable renewable biofuels industry. Biological routes to converting lignin to fuels and chemicals involve depolymerizing lignin using lignin-degrading enzymes that catalyze the breaking of ether and carbon-carbon bonds in the phenolic and non-phenolic subunits of lignin. Laccases are a crucial class of lignin-degrading enzymes and are copper-containing enzymes capable of oxidizing electron-rich organic substrates such as lignin using molecular oxygen as an electron acceptor. The genome of Cerrena unicolor was recently added to the JGI MycoCosm database and has eight laccases. Two of these laccases, designated Lc1 and Lc2, predicted to have the highest likelihood for successful expression in soluble, active form were selected for characterization. Lc1 and Lc2, which share 65% sequence identity, were heterologously expressed in Komagataella pastoris (formerly Pichia pastoris), allowing characterization and comparison of their purified forms. Lc1 and Lc2 had half-lives of 16 min and 185 min at 60°C, respectively, and, based on molecular dynamics simulations, the longer half-life of Lc2 was due to an increased number and persistence of salt bridges compared to Lc1. Using model lignin-like dimers and a nanostructure-initiator mass spectrometry assay to quantify catalysis of specific bond-breaking events, both Lc1 and Lc2 had their highest activity at pH 3 and in combination with syringaldehyde as a mediator, with Lc1 having a higher catalytic efficiency of β-O-4' ether and C-C bond breaking. This comparative study demonstrates the diversity, including thermostability differences, of laccases from the same fungus, and improves our understanding of laccase catalyzed breaking of bonds commonly found in lignin, which will facilitate the developing this important class of enzymes for applications in the conversion of lignin to valuable bioproducts.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123405930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gabriel Santos Viana, Jorge Alef Estevam Lau Bonfim, G. Silva, José Faustino Souza de Carvalho Filho, M. Tokumoto, F. Rangel, R. S. D. Cruz
Technological development made in the field of biomass application allows synthesizing several high-value products, such as furfuraldehyde. Furfural, produced through sequential hydrolysis and dehydration reactions from biomass, is considered a platform molecule and a precursor of several other chemicals and biofuels that are generated following reactions such as hydrogenation, hydrodeoxygenation, and decarboxylation. This review aims to reveal the environmental-friendly mechanisms followed for producing furfural derivatives and the design of catalysts and supports. Redox and acid-base properties of the molecules have been discussed. The stability, the details of the surface area, and the applications of the molecules to reduce the bottlenecks faced in the industrial production of bioproducts have been explored.
{"title":"Design of Heterogeneous Catalysts for the Conversion of Furfural to C5 Derivatives: A Brief Review","authors":"Gabriel Santos Viana, Jorge Alef Estevam Lau Bonfim, G. Silva, José Faustino Souza de Carvalho Filho, M. Tokumoto, F. Rangel, R. S. D. Cruz","doi":"10.21926/cr.2203026","DOIUrl":"https://doi.org/10.21926/cr.2203026","url":null,"abstract":"Technological development made in the field of biomass application allows synthesizing several high-value products, such as furfuraldehyde. Furfural, produced through sequential hydrolysis and dehydration reactions from biomass, is considered a platform molecule and a precursor of several other chemicals and biofuels that are generated following reactions such as hydrogenation, hydrodeoxygenation, and decarboxylation. This review aims to reveal the environmental-friendly mechanisms followed for producing furfural derivatives and the design of catalysts and supports. Redox and acid-base properties of the molecules have been discussed. The stability, the details of the surface area, and the applications of the molecules to reduce the bottlenecks faced in the industrial production of bioproducts have been explored.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115119265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Ayanda, Cecilia C. Oforkansi, O. H. Aremu, Oluwakemi E. Ogunjemiluyi, Ololade L. Olowoyeye, C. Akintayo
In this study, we investigated the degradation of amido black dye in an aqueous solution using ultra-violet (UV) light catalyzed by iron oxide nanoparticles (nano-Fe). The nano-Fe was synthesized by sodium borohydride reduction of ferric chloride solution and was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence spectrophotometry (XRF). The SEM of the nano-Fe showed regular spherical particles, the XRD examination showed a weak and broad peak at Fe (1 1 0), and the XRF study showed that the element with the highest composition was Fe2O3 (60.80%). The degradation experiments showed that the UV light catalyzed by nano-Fe could effectively degrade amido black dye. The nano-Fe/UV system could degrade 5 mg/L of amido black dye up to 93.2% at 254 nm after being irradiated for 60 min. The nano-Fe/UV system could be described by the Langmuir–Hinshelwood kinetic model, and the rate constants (kapp) were 0.0183–0.0323 min−1. Thus, UV light combined with nano-Fe can be applied for the efficient remediation of dye wastewater.
{"title":"Degradation of Amido Black Dye Using Ultra-Violet Light Catalyzed by Iron Oxide Nanoparticles: Kinetics and Mechanism of Degradation","authors":"O. Ayanda, Cecilia C. Oforkansi, O. H. Aremu, Oluwakemi E. Ogunjemiluyi, Ololade L. Olowoyeye, C. Akintayo","doi":"10.21926/cr.2203022","DOIUrl":"https://doi.org/10.21926/cr.2203022","url":null,"abstract":"In this study, we investigated the degradation of amido black dye in an aqueous solution using ultra-violet (UV) light catalyzed by iron oxide nanoparticles (nano-Fe). The nano-Fe was synthesized by sodium borohydride reduction of ferric chloride solution and was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence spectrophotometry (XRF). The SEM of the nano-Fe showed regular spherical particles, the XRD examination showed a weak and broad peak at Fe (1 1 0), and the XRF study showed that the element with the highest composition was Fe2O3 (60.80%). The degradation experiments showed that the UV light catalyzed by nano-Fe could effectively degrade amido black dye. The nano-Fe/UV system could degrade 5 mg/L of amido black dye up to 93.2% at 254 nm after being irradiated for 60 min. The nano-Fe/UV system could be described by the Langmuir–Hinshelwood kinetic model, and the rate constants (kapp) were 0.0183–0.0323 min−1. Thus, UV light combined with nano-Fe can be applied for the efficient remediation of dye wastewater.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115398118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Silva, Laís Nerys, Carlos Silva, E. Borba, T. Leite, T. Silva, A. Sena
Macambira plant (Bromelia laciniosa Mart. Ex Shult. & Schult. f.) is a species belonging to the family Bromeliaceae, which is distributed widely in the hinterlands of northeastern Brazil, from Bahia to Piauí states. The plants of this species contain an enzyme complex named bromelain, which has great potential for therapeutic applications. In the present study, bromelain derived from Bromelia laciniosa leaves was assessed for its thermodynamic properties and in vitro cytotoxic and healing activities. Bromelain was extracted from the leaves and partitioned using ethanol. The partially purified bromelain was then characterized to determine the optimum pH and temperature and the kinetic and thermodynamic parameters. The partially purified bromelain derived from macambira leaves exhibited its highest activity at 47°C and pH 7, when the Km and Vmax values of 2.26 µM and 2.083 U/mL, respectively. The half-life of this bromelain at 47°C was 5.78 h. At 47°C, the Gibbs's free energy, enthalpy, and entropy values reached 89, 53.54, and –0.11 kJ/mol K, respectively. In the SDS-PAGE analysis, bromelain appeared as the main protein band, with an estimated molecular mass of 33 kDa. The in vitro cytotoxic activity and wound healing effects were determined using the MTT assay and Scratch assay, respectively. These assays were performed on the non-neoplastic cell lines L-929 and PBMC and the human tumor cell lines MCF-7, HCT-116, and NCI-H292. Bromelain exhibited a positive healing activity with a change rate similar to that observed for the control. In addition, bromelain exhibited cytotoxic activity against NCI-H292 tumor cells and chemopreventive potential. These results indicate that bromelain derived from macambira leaves may be utilized as a potential ingredient in pharmaceutical formulations, for various healing and chemopreventive purposes and as an alternative to the bromelain extracted from pineapple. In addition, the biochemical characteristics of this bromelain could find application in the food industry. Future studies should, therefore, focus on deciphering the action mechanisms underlying the activities of bromelain observed in the present study to further confirm and enhance its application potential for therapeutic purposes.
{"title":"Biochemical Characteristics and Healing Activity of Bromelia laciniosa Leaf Protease","authors":"D. Silva, Laís Nerys, Carlos Silva, E. Borba, T. Leite, T. Silva, A. Sena","doi":"10.21926/cr.2203024","DOIUrl":"https://doi.org/10.21926/cr.2203024","url":null,"abstract":"Macambira plant (Bromelia laciniosa Mart. Ex Shult. & Schult. f.) is a species belonging to the family Bromeliaceae, which is distributed widely in the hinterlands of northeastern Brazil, from Bahia to Piauí states. The plants of this species contain an enzyme complex named bromelain, which has great potential for therapeutic applications. In the present study, bromelain derived from Bromelia laciniosa leaves was assessed for its thermodynamic properties and in vitro cytotoxic and healing activities. Bromelain was extracted from the leaves and partitioned using ethanol. The partially purified bromelain was then characterized to determine the optimum pH and temperature and the kinetic and thermodynamic parameters. The partially purified bromelain derived from macambira leaves exhibited its highest activity at 47°C and pH 7, when the Km and Vmax values of 2.26 µM and 2.083 U/mL, respectively. The half-life of this bromelain at 47°C was 5.78 h. At 47°C, the Gibbs's free energy, enthalpy, and entropy values reached 89, 53.54, and –0.11 kJ/mol K, respectively. In the SDS-PAGE analysis, bromelain appeared as the main protein band, with an estimated molecular mass of 33 kDa. The in vitro cytotoxic activity and wound healing effects were determined using the MTT assay and Scratch assay, respectively. These assays were performed on the non-neoplastic cell lines L-929 and PBMC and the human tumor cell lines MCF-7, HCT-116, and NCI-H292. Bromelain exhibited a positive healing activity with a change rate similar to that observed for the control. In addition, bromelain exhibited cytotoxic activity against NCI-H292 tumor cells and chemopreventive potential. These results indicate that bromelain derived from macambira leaves may be utilized as a potential ingredient in pharmaceutical formulations, for various healing and chemopreventive purposes and as an alternative to the bromelain extracted from pineapple. In addition, the biochemical characteristics of this bromelain could find application in the food industry. Future studies should, therefore, focus on deciphering the action mechanisms underlying the activities of bromelain observed in the present study to further confirm and enhance its application potential for therapeutic purposes.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130872052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. F. M. Rocha, L. Ferreira, Maria Marques, R. Bitzer, M. Nascimento
We synthesized and spectroscopically characterized a new heterotrimetallic {Ti2Ni} ethylene (co)polymerization precatalyst containing one (α-diimine)NiBr2 and two (phenoxy-imine)TiCl4 scaffolds. Its calculated structure was investigated at the DFT B3LYP/LACVP** level. Our calculations showed that the titanium(IV) centers were in a slightly distorted trigonal bipyramidal environment, and the average Ti···Ni distance was 8.76 Å. The precatalyst was used for synthesizing polyethylene and ethylene copolymers. The results of GPC analyses showed that the obtained polyethylenes had the desired bimodal molecular weight distributions. The FTIR spectra revealed that polydispersity decreased as the vinyl end-group content increased. These results suggested that high mechanical resistance can increase the mechanical energy needed for processing the material. All 13C NMR signals were assigned to short-chain branches with specific spatial arrangements along the polymer backbone. The chain walking mechanism of branch formation controls the spacing and conformational arrangements between these short chains.
{"title":"Homogeneous {Ti2Ni} Heterotrinuclear Catalyst for Ethylene Polymerization and Copolymerization","authors":"L. F. M. Rocha, L. Ferreira, Maria Marques, R. Bitzer, M. Nascimento","doi":"10.21926/cr.2203020","DOIUrl":"https://doi.org/10.21926/cr.2203020","url":null,"abstract":"We synthesized and spectroscopically characterized a new heterotrimetallic {Ti2Ni} ethylene (co)polymerization precatalyst containing one (α-diimine)NiBr2 and two (phenoxy-imine)TiCl4 scaffolds. Its calculated structure was investigated at the DFT B3LYP/LACVP** level. Our calculations showed that the titanium(IV) centers were in a slightly distorted trigonal bipyramidal environment, and the average Ti···Ni distance was 8.76 Å. The precatalyst was used for synthesizing polyethylene and ethylene copolymers. The results of GPC analyses showed that the obtained polyethylenes had the desired bimodal molecular weight distributions. The FTIR spectra revealed that polydispersity decreased as the vinyl end-group content increased. These results suggested that high mechanical resistance can increase the mechanical energy needed for processing the material. All 13C NMR signals were assigned to short-chain branches with specific spatial arrangements along the polymer backbone. The chain walking mechanism of branch formation controls the spacing and conformational arrangements between these short chains.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127071854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiarui Fang, Ziheng Li, Xiruo Bai, Yichu Zhang, Jiahui Liu, Dan Wang, Ye Yao
TiO2 (001) crystal plane exhibits molecular adsorption and photocatalytic activity. The loading capacity of reactive oxygen species present on crystal planes helps in the significant improvement of catalytic activity. The methods of synthesis and conditions of existence significantly affect the molecular adsorption properties of crystal planes, which in turn affects the ability of the system to load reactive oxygen species. Herein, we report the simulation of the molecular adsorption behavior on the TiO2 (001) using the density functional theory technique. The results show that the crystal plane doped with Co2+ produces an oxygen defect and chemisorbs O2 molecules present in the vicinity. Under conditions of adequate O2 concentration, the second O2 molecule is chemisorbed. This significantly improves the ability of the crystal plane to store oxygen. However, the undoped planes adsorb H2O molecules and undergo hydroxylation under the synthesis and processing conditions. The ability to adsorb O2 molecules is poor. The doping of Co2+ increases the electrical conductivity of the crystal plane and the electrical sensitivity of adsorbed O2 molecules, which is beneficial to the further improvement of the catalytic activity of the system. Fourier transform infrared spectroscopy (FTIR), and electrochemical impedance spectroscopy (EIS) techniques were used to confirm these results. The results indicate that the adsorption capacity of O2 present on the TiO2 (001) crystal plane can be changed by Co2+ doping to improve the catalytic activity of the crystal plane.
{"title":"Co2+ Doping and Molecular Adsorption Behavior of Anatase TiO2 (001) Crystal Plane","authors":"Jiarui Fang, Ziheng Li, Xiruo Bai, Yichu Zhang, Jiahui Liu, Dan Wang, Ye Yao","doi":"10.21926/cr.2203018","DOIUrl":"https://doi.org/10.21926/cr.2203018","url":null,"abstract":"TiO2 (001) crystal plane exhibits molecular adsorption and photocatalytic activity. The loading capacity of reactive oxygen species present on crystal planes helps in the significant improvement of catalytic activity. The methods of synthesis and conditions of existence significantly affect the molecular adsorption properties of crystal planes, which in turn affects the ability of the system to load reactive oxygen species. Herein, we report the simulation of the molecular adsorption behavior on the TiO2 (001) using the density functional theory technique. The results show that the crystal plane doped with Co2+ produces an oxygen defect and chemisorbs O2 molecules present in the vicinity. Under conditions of adequate O2 concentration, the second O2 molecule is chemisorbed. This significantly improves the ability of the crystal plane to store oxygen. However, the undoped planes adsorb H2O molecules and undergo hydroxylation under the synthesis and processing conditions. The ability to adsorb O2 molecules is poor. The doping of Co2+ increases the electrical conductivity of the crystal plane and the electrical sensitivity of adsorbed O2 molecules, which is beneficial to the further improvement of the catalytic activity of the system. Fourier transform infrared spectroscopy (FTIR), and electrochemical impedance spectroscopy (EIS) techniques were used to confirm these results. The results indicate that the adsorption capacity of O2 present on the TiO2 (001) crystal plane can be changed by Co2+ doping to improve the catalytic activity of the crystal plane.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132224124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Menezes, G. M. Paula, L. A. Lima, M. Rodrigues, F. Fernandes
In this study, we investigated the oligomerization mechanism of the Fischer-Tropsch synthesis catalyzed by a cobalt-based catalyst supported by SBA-15. The Co/SBA-15 catalyst contained 20% w/w of cobalt. It was prepared by the wet impregnation method and characterized by X-ray diffraction (XRD), N2 adsorption-desorption, temperature-programmed reduction (TPR), and scanning electron microscopy coupled to X-ray energy dispersion spectroscopy (SEM-EDS). The FT synthesis was conducted in a slurry bed reactor operating at 240–270°C, 2.0–3.0 MPa, and 1:1–2:1 H2:CO ratio (mol:mol). An oligomerization model, based on alkyl and alkenyl mechanisms for hydrocarbon chain propagation, was used for product distribution. Impregnation with cobalt and calcination did not alter the structure of SBA-15. Cobalt oxides, including Co2O3 and Co3O4, were the active phases of the reaction. Adding cobalt to the support lowered the specific surface area and the pore volume of the support but did not change the structure of SBA-15. Fischer-Tropsch synthesis and C5+ hydrocarbon selectivity increased at a low H2:CO ratio (1.0) and low temperatures (240–255°C). The content of branched-chain paraffin and olefins increased with a decrease in the H2:CO ratio and temperature. The parameters of the model were estimated, and the assumption of a dual mechanism was satisfied.
{"title":"Fischer-Tropsch Synthesis on Co/SBA-15 Catalyst: Characterization and Oligomerization Modeling","authors":"V. Menezes, G. M. Paula, L. A. Lima, M. Rodrigues, F. Fernandes","doi":"10.21926/cr.2203023","DOIUrl":"https://doi.org/10.21926/cr.2203023","url":null,"abstract":"In this study, we investigated the oligomerization mechanism of the Fischer-Tropsch synthesis catalyzed by a cobalt-based catalyst supported by SBA-15. The Co/SBA-15 catalyst contained 20% w/w of cobalt. It was prepared by the wet impregnation method and characterized by X-ray diffraction (XRD), N2 adsorption-desorption, temperature-programmed reduction (TPR), and scanning electron microscopy coupled to X-ray energy dispersion spectroscopy (SEM-EDS). The FT synthesis was conducted in a slurry bed reactor operating at 240–270°C, 2.0–3.0 MPa, and 1:1–2:1 H2:CO ratio (mol:mol). An oligomerization model, based on alkyl and alkenyl mechanisms for hydrocarbon chain propagation, was used for product distribution. Impregnation with cobalt and calcination did not alter the structure of SBA-15. Cobalt oxides, including Co2O3 and Co3O4, were the active phases of the reaction. Adding cobalt to the support lowered the specific surface area and the pore volume of the support but did not change the structure of SBA-15. Fischer-Tropsch synthesis and C5+ hydrocarbon selectivity increased at a low H2:CO ratio (1.0) and low temperatures (240–255°C). The content of branched-chain paraffin and olefins increased with a decrease in the H2:CO ratio and temperature. The parameters of the model were estimated, and the assumption of a dual mechanism was satisfied.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"195 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115651329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Huseynova, Gulbeniz Мuхtаrоvа, N. Aliyeva, Gular Gаsimоvа, Sanubar Rаshidоvа
This article provides an overview of zeolite-containing catalysts used in the alkylation of benzene and toluene with olefins, isobutane with butenes and butane-butene fractions, gasoline and oil fractions with olefins, propane-propylene, and butane-butylene fractions of catalytic cracking. Zeolites have various types of structures, including BEA, MFI, MWW, FAU, etc., which differ in pore size and the number and location of the channels. High-silica zeolites have a large pore volume, high acidity, good hydrothermal stability, and molecular sieve properties that provide high selectivity in alkylation processes.
{"title":"Zeolite-Containing Catalysts in Alkylation Processes","authors":"G. Huseynova, Gulbeniz Мuхtаrоvа, N. Aliyeva, Gular Gаsimоvа, Sanubar Rаshidоvа","doi":"10.21926/cr.2203019","DOIUrl":"https://doi.org/10.21926/cr.2203019","url":null,"abstract":"This article provides an overview of zeolite-containing catalysts used in the alkylation of benzene and toluene with olefins, isobutane with butenes and butane-butene fractions, gasoline and oil fractions with olefins, propane-propylene, and butane-butylene fractions of catalytic cracking. Zeolites have various types of structures, including BEA, MFI, MWW, FAU, etc., which differ in pore size and the number and location of the channels. High-silica zeolites have a large pore volume, high acidity, good hydrothermal stability, and molecular sieve properties that provide high selectivity in alkylation processes.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129626760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rational design of efficient electrocatalysts for oxygen reduction reaction (ORR) is the key to developing fuel cells and metal-air batteries. Carbon-supported iron-based materials, as the most promising electrocatalysts for ORR, have drawn much attention as they are cost-effective and exhibit high activity. In this work, a three-dimensional (3D) Fe3O4-decorated N-doped graphene aerogel (Fe3O4/NGA) catalyst was synthesized following a simple hydrothermal method which was followed by an annealing process. The complex formed between Fe2+ and phenanthroline was first used as the precursor of iron and nitrogen sources to synthesize Fe3O4 nanocrystals. Benefiting from the synergistic effect between the uniformly distributed Fe3O4 nanoparticles and the 3D porous N-doped graphene aerogel, Fe3O4/NGA exhibits good electrocatalytic activity with a half-wave potential of 0.81 V. It also exhibits excellent selectivity with low HO2- yield (<5%), and excellent long-time stability. The encouraging results demonstrate that the Fe3O4/NGA composite catalyst is a promising candidate that can be used for the fabrication of non-precious electrocatalyst for ORR.
{"title":"3D Fe3O4-decorated Nitrogen-doped Graphene Aerogel as a Highly Durable Electrocatalyst for Oxygen Reduction Reactions","authors":"Jia Yu, Haiyan Jing, Zongdeng Wu, Boyuan Liu, Wu Lei, Q. Hao","doi":"10.21926/cr.2202016","DOIUrl":"https://doi.org/10.21926/cr.2202016","url":null,"abstract":"The rational design of efficient electrocatalysts for oxygen reduction reaction (ORR) is the key to developing fuel cells and metal-air batteries. Carbon-supported iron-based materials, as the most promising electrocatalysts for ORR, have drawn much attention as they are cost-effective and exhibit high activity. In this work, a three-dimensional (3D) Fe3O4-decorated N-doped graphene aerogel (Fe3O4/NGA) catalyst was synthesized following a simple hydrothermal method which was followed by an annealing process. The complex formed between Fe2+ and phenanthroline was first used as the precursor of iron and nitrogen sources to synthesize Fe3O4 nanocrystals. Benefiting from the synergistic effect between the uniformly distributed Fe3O4 nanoparticles and the 3D porous N-doped graphene aerogel, Fe3O4/NGA exhibits good electrocatalytic activity with a half-wave potential of 0.81 V. It also exhibits excellent selectivity with low HO2- yield (<5%), and excellent long-time stability. The encouraging results demonstrate that the Fe3O4/NGA composite catalyst is a promising candidate that can be used for the fabrication of non-precious electrocatalyst for ORR.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121898292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solid base catalysts consisting of MgO modified with 10 mol% ZnO (ZnO/MgO) were prepared by depositing zinc(II) acetylacetonate (Zn(acac)2) in polar and nonpolar organic solvents on the surface of MgO and Mg(OH)2. The process was followed by thermal decomposition in air at 773 K over a period of 3 h. The activity of MgO modified with Zn(acac)2 for base-catalyzed retroaldol reaction (the decomposition of diacetone alcohol (4-hydroxy-4-methyl-2-pentanone) to acetone) at 299 K was higher than the activity of unmodified MgO prepared by thermal decomposition of Mg(OH)2. The activity of the catalysts prepared by depositing Zn(acac)2 on Mg(OH)2 was lower than that of unmodified MgO. Analysis of X-ray diffraction patterns revealed the presence of highly intense peaks, which were assigned to the ZnO units in the samples with high catalytic activity. ZnO was deposited in the form of large particles on the surface of MgO in the catalysts with high activity.
{"title":"Synthesis of a Solid Base Catalyst Formed from Zinc(II) Acetylacetonate and Consisting of MgO Modified with ZnO","authors":"H. Matsuhashi","doi":"10.21926/cr.2202015","DOIUrl":"https://doi.org/10.21926/cr.2202015","url":null,"abstract":"Solid base catalysts consisting of MgO modified with 10 mol% ZnO (ZnO/MgO) were prepared by depositing zinc(II) acetylacetonate (Zn(acac)2) in polar and nonpolar organic solvents on the surface of MgO and Mg(OH)2. The process was followed by thermal decomposition in air at 773 K over a period of 3 h. The activity of MgO modified with Zn(acac)2 for base-catalyzed retroaldol reaction (the decomposition of diacetone alcohol (4-hydroxy-4-methyl-2-pentanone) to acetone) at 299 K was higher than the activity of unmodified MgO prepared by thermal decomposition of Mg(OH)2. The activity of the catalysts prepared by depositing Zn(acac)2 on Mg(OH)2 was lower than that of unmodified MgO. Analysis of X-ray diffraction patterns revealed the presence of highly intense peaks, which were assigned to the ZnO units in the samples with high catalytic activity. ZnO was deposited in the form of large particles on the surface of MgO in the catalysts with high activity.","PeriodicalId":178524,"journal":{"name":"Catalysis Research","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131382513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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