Suzuki-Miyaura reaction of aryl halides with phenylboronic acid using a heterogeneous palladium catalyst based on activated carbons(AC) was systematically investigated in this work. Two different reaction modes(batch ...Suzuki-Miyaura reaction of aryl halides with phenylboronic acid using a heterogeneous palladium catalyst based on activated carbons(AC) was systematically investigated in this work. Two different reaction modes(batch procedure and continuous-flow procedure) were used to study the variations of reaction processing. The heterogeneous catalysts presented excellent reactivity and recyclability for iodobenzene and bromobenzene substrates in batch mode, which can be attributed to stabilization of Pd nanoparticles by the thiol and amino groups on the AC supports. However, significant dehalogenation in the reaction mixture and Pd leaching from the heterogeneous catalysts were observed in continuous-flow mode.This unique phenomenon in continuous-flow mode resulted in a dramatic decline in reaction selectivity and durability of heterogeneous catalysts comparing with that of batch mode. In addition, the heterogeneous Pd catalysts with thiol-and amino-modified AC supports exhibited different reactivity and durability in batch and continuous-flow mode owing to the difference of interaction between Pd species and AC supports.展开更多
Ten kinds of activated carbon from different raw materials were used as supports to prepare ruthenium catalysts. N_2 physisorption and CO chemisorption were carried out to investigate the pore size distribution and th...Ten kinds of activated carbon from different raw materials were used as supports to prepare ruthenium catalysts. N_2 physisorption and CO chemisorption were carried out to investigate the pore size distribution and the ruthenium dispersion of the catalysts. It was found that the Ru dispersion of the catalyst was closely related to not only the texture of carbon support but also the purity of activated carbon. The activities of a series of the carbon-supported barium-promoted Ru catalysts for ammonia synthesis were measured at 425 ℃, 10 0 MPa and 10 000 h -1. The result shows that the same raw material activated carbon, with a high purity, high surface area, large pore volume and reasonable pore size distribution might disperse ruthenium and promoter sufficiently, which activated carbon as support, could be used to manufacture ruthenium catalyst with a high activity for ammonia synthesis. The different raw material activated carbon as the support would greatly influence the catalytic properties of the ruthenium catalyst for ammonia synthesis. For example, with coconut shell carbon(AC1) as the support, the ammonia concentration in the effluent was 13 17% over 4%Ru-BaO/AC1 catalyst, while with the desulfurized coal carbon(AC10) as the support, that in the effluent was only 1 37% over 4%Ru-BaO/AC10 catalyst.展开更多
A catalytic approach using a synthesized iron and manganese oxide-supported granular activated carbon(Fe-Mn GAC) under a dielectric barrier discharge(DBD) plasma was investigated to enhance the degradation of oxytetra...A catalytic approach using a synthesized iron and manganese oxide-supported granular activated carbon(Fe-Mn GAC) under a dielectric barrier discharge(DBD) plasma was investigated to enhance the degradation of oxytetracycline(OTC) in water. The prepared Fe-Mn GAC was characterized by x-ray diffraction and scanning electron microscopy, and the results showed that the bimetallic oxides had been successfully spread on the GAC surface. The experimental results showed that the DBD?+?Fe-Mn GAC exhibited better OTC removal efficiency than the sole DBD and DBD?+?virgin GAC systems. Increasing the fabricated catalyst and discharge voltage was favorable to the antibiotic elimination and energy yield in the hybrid process. The coupling process could be elucidated by the ozone decomposition after Fe-Mn GAC addition, and highly hydroxyl and superoxide radicals both play significant roles in the decontamination. The main intermediate products were identified by HPLC-MS to study the mechanism in the collaborative system.展开更多
The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was ch...The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM).The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy(FTIR),13C-nuclear magnetic resonance(NMR) and XRD,respectively.The catalyst showed excellent activity and reusability in promoting the fabrication of PK.It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/(gPd·h) at Pd content of 8.63wt%.The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.展开更多
Silica, alumina, and activated carbon supported iron-cobalt catalysts were prepared by incipient wetness impregnation. These catalysts have been characterized by BET, X-ray diffraction （XRD）, and temperature-program...Silica, alumina, and activated carbon supported iron-cobalt catalysts were prepared by incipient wetness impregnation. These catalysts have been characterized by BET, X-ray diffraction （XRD）, and temperature-programmed reduction （TPR）. Activity and selectivity of iron-cobalt supported on different carriers for CO hydrogenation were studied under the conditions of 1.5 MPa, 493 K, 630 h^-1, and H2/CO ratio of 1.6. The results indicate that the activity, C4 olefin/（C4 olefin＋C4 paraffin） ratio, and C5 olefin/（C5 olefin＋C5 paraffin） decrease in the order of Fe-Co/SiO2, Fe-Co/AC1, Fe-Co/Al2O3 and Fe- Co/AC2. The activity of Fe-Co/SiO2 reached a maximum. The results of TPR show that the Fe-Co/SiO2 catalyst is to some extent different. XRD patterns show that the Fe-Co/SiO2 catalyst differs significantly from the others; it has two diffraction peaks. The active spinel phase is correlated with the supports.展开更多
Atmospheric high frequency cold plasma jet was applied to modify Ni/SiO2 catalysts. The catalysts prepared by two different methods with plasma jet were compared with conventional catalysts. BET, XRD, H2-TPD and high-...Atmospheric high frequency cold plasma jet was applied to modify Ni/SiO2 catalysts. The catalysts prepared by two different methods with plasma jet were compared with conventional catalysts. BET, XRD, H2-TPD and high-resolution transmission electron microscopy （HRTEM） were used to characterize these catalysts. The results showed that the catalyst prepared with plasma jet had higher nickel dispersion, larger specific surface area and smaller nickel particle size, about 5 nanometres. Detailed analyses revealed that improved structure and characteristic of the plasma catalyst were benefited from the large amount of hydrogen atoms in the plasma jet, by which the catalyst reduction can be easily achieved in shorter period of time at lower temperature, thus avoiding sintering and conglomeration of the active particles and the support. The activity of catalysts was investigated in the methane reforming with CO2. It is shown that the conversions of CH4 and CO2, the yields of H2 and CO were all significantly increased for the plasma catalysts.展开更多
Mesoporous Co3 O4(meso-Co3 O4)-supported Pt(0.53 wt.%Pt/meso-Co304)was synthesized via the KIT-6-templating and polyvinyl alcohol(PVA)-assisted reduction routes.Mesoporous CoO(meso-CoO)was fabricated through in situ r...Mesoporous Co3 O4(meso-Co3 O4)-supported Pt(0.53 wt.%Pt/meso-Co304)was synthesized via the KIT-6-templating and polyvinyl alcohol(PVA)-assisted reduction routes.Mesoporous CoO(meso-CoO)was fabricated through in situ reduction of meso-Co304 with glycerol,and the 0.18-0.69 wt.%Pt/meso-CoO samples were generated by the PVA-assisted reduction method.Meso-Co3 O4 and meso-CoO were of cubic crystal structure and the Pt nanoparticles(NPs)with a uniform size of ca.2 nm were well distributed on the mesoCo3 O4 or meso-CoO surface.The 0.56 wt%Pt/meso-CoO(0.56 Pt/meso-CoO)sample performed the best in benzene combustion(T50%=156℃and T90%=186℃at a space velocity of 80,000 mL/(g h)).Introducing water vapor or C02 with a certain concentration led to partial deactivation of 0.56 Pt/meso-CoO and such a deactivation was reversible.We think that the superior catalytic activity of 0.56 Pt/meso-CoO was intimately related to its good oxygen activation and benzene adsorption ability.展开更多
Cylindrical coconut activated carbon（CCAC） support was graphitized at a high temperature（1900 ℃） in argon, then oxidized with an O2-N2-H2O mixture, and treated with nitric acid. Pretreatment of carbon support on ...Cylindrical coconut activated carbon（CCAC） support was graphitized at a high temperature（1900 ℃） in argon, then oxidized with an O2-N2-H2O mixture, and treated with nitric acid. Pretreatment of carbon support on its mechanical strength, physical structure, chemical composition and surface properties of cylindrical CCAC support was investigated by X-ray diffraction（XRD）, surface area analysis, scanning electron microscopy（SEM）, energy dis- persive spectroscopy（EDS）, thermogravimetric-differential thermogravimetric（TG-DTG） analysis and temperature programmed desorption-mass spectrometry（TPD-MS）, and the effect of CCAC support on the catalytic activities was also studied. The results show that the degree of graphitization, the purity（phosphorus, sulphur）, pore struc- ture（micropore, mesopore） and oxygen-containing functional groups（--COOH, --OH, --COOR） of carbon supports are obviously different, which have a great influence on the performance of Ru-based catalysts. After a series of pre- treatments, the surface physical and chemical properties of the commercial CCAC are modified and improved, and the activity of as-prepared Ru/AC catalyst is increased significantly.展开更多
A series of active carbon supported ruthenium based catalysts, promoted by alkali and alkaline earth nitrate, are prepared by impregnation method and with RuCl 3·3H 2O as precursor. Effects of support, promoter a...A series of active carbon supported ruthenium based catalysts, promoted by alkali and alkaline earth nitrate, are prepared by impregnation method and with RuCl 3·3H 2O as precursor. Effects of support, promoter and preparation conditions on catalytic activity are discussed. The catalytic activity is evaluated with a fixed bed micro reactor at lower pressure. The results show that the impregnation sequence affects the catalytic activity obviously. Ba Ru K/C is the preferred impregnation sequence. And effects of nature, producing area and pre treatment of the support on catalytic activity are also examined. Catalytic activity increases with the amount of Ru deposited on the support, it attains maximum when Ru loading is 8%. Optimal molar ratio of promoter to Ru is 10.展开更多
基金the support of the National Natural Science Foundation of China (20222809, 21978146)TsinghuaFoshan Innovation Special Fund (2021THFS0214)。
文摘Suzuki-Miyaura reaction of aryl halides with phenylboronic acid using a heterogeneous palladium catalyst based on activated carbons(AC) was systematically investigated in this work. Two different reaction modes(batch procedure and continuous-flow procedure) were used to study the variations of reaction processing. The heterogeneous catalysts presented excellent reactivity and recyclability for iodobenzene and bromobenzene substrates in batch mode, which can be attributed to stabilization of Pd nanoparticles by the thiol and amino groups on the AC supports. However, significant dehalogenation in the reaction mixture and Pd leaching from the heterogeneous catalysts were observed in continuous-flow mode.This unique phenomenon in continuous-flow mode resulted in a dramatic decline in reaction selectivity and durability of heterogeneous catalysts comparing with that of batch mode. In addition, the heterogeneous Pd catalysts with thiol-and amino-modified AC supports exhibited different reactivity and durability in batch and continuous-flow mode owing to the difference of interaction between Pd species and AC supports.
基金Supported by the Science &Technical Ministry of China( No.2 0 0 1BA3 2 2 C) ,the Science &Technical Department ofFujian Province( No.2 0 0 0 F0 0 2 ) and the Science &Technical Development Foundation of Fuzhou U niversity( No.XKJQD-0 10 2 )
文摘Ten kinds of activated carbon from different raw materials were used as supports to prepare ruthenium catalysts. N_2 physisorption and CO chemisorption were carried out to investigate the pore size distribution and the ruthenium dispersion of the catalysts. It was found that the Ru dispersion of the catalyst was closely related to not only the texture of carbon support but also the purity of activated carbon. The activities of a series of the carbon-supported barium-promoted Ru catalysts for ammonia synthesis were measured at 425 ℃, 10 0 MPa and 10 000 h -1. The result shows that the same raw material activated carbon, with a high purity, high surface area, large pore volume and reasonable pore size distribution might disperse ruthenium and promoter sufficiently, which activated carbon as support, could be used to manufacture ruthenium catalyst with a high activity for ammonia synthesis. The different raw material activated carbon as the support would greatly influence the catalytic properties of the ruthenium catalyst for ammonia synthesis. For example, with coconut shell carbon(AC1) as the support, the ammonia concentration in the effluent was 13 17% over 4%Ru-BaO/AC1 catalyst, while with the desulfurized coal carbon(AC10) as the support, that in the effluent was only 1 37% over 4%Ru-BaO/AC10 catalyst.
基金supported by National Natural Science Foundation of China (No. 51608468)High School Science and Technology Research Project of Hebei Province (No. QN2018258)+1 种基金China Postdoctoral Science Foundation (Nos. 2015M580216 and 2016M601285)Hebei Province Preferred Postdoctoral Science Foundation (No. B2016003019)
文摘A catalytic approach using a synthesized iron and manganese oxide-supported granular activated carbon(Fe-Mn GAC) under a dielectric barrier discharge(DBD) plasma was investigated to enhance the degradation of oxytetracycline(OTC) in water. The prepared Fe-Mn GAC was characterized by x-ray diffraction and scanning electron microscopy, and the results showed that the bimetallic oxides had been successfully spread on the GAC surface. The experimental results showed that the DBD?+?Fe-Mn GAC exhibited better OTC removal efficiency than the sole DBD and DBD?+?virgin GAC systems. Increasing the fabricated catalyst and discharge voltage was favorable to the antibiotic elimination and energy yield in the hybrid process. The coupling process could be elucidated by the ozone decomposition after Fe-Mn GAC addition, and highly hydroxyl and superoxide radicals both play significant roles in the decontamination. The main intermediate products were identified by HPLC-MS to study the mechanism in the collaborative system.
基金Supported by the National Natural Science Foundation of China(No.20476080)Tianjin Natural Science Foundation(No.07JCYBJC00600)
文摘The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM).The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy(FTIR),13C-nuclear magnetic resonance(NMR) and XRD,respectively.The catalyst showed excellent activity and reusability in promoting the fabrication of PK.It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/(gPd·h) at Pd content of 8.63wt%.The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.
文摘Silica, alumina, and activated carbon supported iron-cobalt catalysts were prepared by incipient wetness impregnation. These catalysts have been characterized by BET, X-ray diffraction （XRD）, and temperature-programmed reduction （TPR）. Activity and selectivity of iron-cobalt supported on different carriers for CO hydrogenation were studied under the conditions of 1.5 MPa, 493 K, 630 h^-1, and H2/CO ratio of 1.6. The results indicate that the activity, C4 olefin/（C4 olefin＋C4 paraffin） ratio, and C5 olefin/（C5 olefin＋C5 paraffin） decrease in the order of Fe-Co/SiO2, Fe-Co/AC1, Fe-Co/Al2O3 and Fe- Co/AC2. The activity of Fe-Co/SiO2 reached a maximum. The results of TPR show that the Fe-Co/SiO2 catalyst is to some extent different. XRD patterns show that the Fe-Co/SiO2 catalyst differs significantly from the others; it has two diffraction peaks. The active spinel phase is correlated with the supports.
基金National Natural Science Foundation of China(No.10475060)the Ministry of Sciences and Technologies of China(2005CB221406)
文摘Atmospheric high frequency cold plasma jet was applied to modify Ni/SiO2 catalysts. The catalysts prepared by two different methods with plasma jet were compared with conventional catalysts. BET, XRD, H2-TPD and high-resolution transmission electron microscopy （HRTEM） were used to characterize these catalysts. The results showed that the catalyst prepared with plasma jet had higher nickel dispersion, larger specific surface area and smaller nickel particle size, about 5 nanometres. Detailed analyses revealed that improved structure and characteristic of the plasma catalyst were benefited from the large amount of hydrogen atoms in the plasma jet, by which the catalyst reduction can be easily achieved in shorter period of time at lower temperature, thus avoiding sintering and conglomeration of the active particles and the support. The activity of catalysts was investigated in the methane reforming with CO2. It is shown that the conversions of CH4 and CO2, the yields of H2 and CO were all significantly increased for the plasma catalysts.
基金supported by the National Natural Science Foundation of China(Nos.21677004,21876006,21607005,21622701,21477005,and U1507108)National Natural Science Foundation of China-Liaoning Provincial People’s Government Joint Fund(U1908204)Foundation on the Creative Research Team Construction Promotion Project of Beijing Municipal Institutions(IDHT20190503)
文摘Mesoporous Co3 O4(meso-Co3 O4)-supported Pt(0.53 wt.%Pt/meso-Co304)was synthesized via the KIT-6-templating and polyvinyl alcohol(PVA)-assisted reduction routes.Mesoporous CoO(meso-CoO)was fabricated through in situ reduction of meso-Co304 with glycerol,and the 0.18-0.69 wt.%Pt/meso-CoO samples were generated by the PVA-assisted reduction method.Meso-Co3 O4 and meso-CoO were of cubic crystal structure and the Pt nanoparticles(NPs)with a uniform size of ca.2 nm were well distributed on the mesoCo3 O4 or meso-CoO surface.The 0.56 wt%Pt/meso-CoO(0.56 Pt/meso-CoO)sample performed the best in benzene combustion(T50%=156℃and T90%=186℃at a space velocity of 80,000 mL/(g h)).Introducing water vapor or C02 with a certain concentration led to partial deactivation of 0.56 Pt/meso-CoO and such a deactivation was reversible.We think that the superior catalytic activity of 0.56 Pt/meso-CoO was intimately related to its good oxygen activation and benzene adsorption ability.
基金Supported by the Fundamental Research Funds for the Central Universities, China（No.2013QN81004） and the Zhejiang Postdoctoral Science Foundation, China（No.Bshl201017）.
文摘Cylindrical coconut activated carbon（CCAC） support was graphitized at a high temperature（1900 ℃） in argon, then oxidized with an O2-N2-H2O mixture, and treated with nitric acid. Pretreatment of carbon support on its mechanical strength, physical structure, chemical composition and surface properties of cylindrical CCAC support was investigated by X-ray diffraction（XRD）, surface area analysis, scanning electron microscopy（SEM）, energy dis- persive spectroscopy（EDS）, thermogravimetric-differential thermogravimetric（TG-DTG） analysis and temperature programmed desorption-mass spectrometry（TPD-MS）, and the effect of CCAC support on the catalytic activities was also studied. The results show that the degree of graphitization, the purity（phosphorus, sulphur）, pore struc- ture（micropore, mesopore） and oxygen-containing functional groups（--COOH, --OH, --COOR） of carbon supports are obviously different, which have a great influence on the performance of Ru-based catalysts. After a series of pre- treatments, the surface physical and chemical properties of the commercial CCAC are modified and improved, and the activity of as-prepared Ru/AC catalyst is increased significantly.
文摘A series of active carbon supported ruthenium based catalysts, promoted by alkali and alkaline earth nitrate, are prepared by impregnation method and with RuCl 3·3H 2O as precursor. Effects of support, promoter and preparation conditions on catalytic activity are discussed. The catalytic activity is evaluated with a fixed bed micro reactor at lower pressure. The results show that the impregnation sequence affects the catalytic activity obviously. Ba Ru K/C is the preferred impregnation sequence. And effects of nature, producing area and pre treatment of the support on catalytic activity are also examined. Catalytic activity increases with the amount of Ru deposited on the support, it attains maximum when Ru loading is 8%. Optimal molar ratio of promoter to Ru is 10.
