An iron-containing SBA-15(Fe-SBA-15) has been synthesized via one-pot hydrothermal method under weak acidic conditions. A series of characterizations show nanocomposite materials of iron particles supported over mes...An iron-containing SBA-15(Fe-SBA-15) has been synthesized via one-pot hydrothermal method under weak acidic conditions. A series of characterizations show nanocomposite materials of iron particles supported over mesostructured materials. The catalytic activity of these iron-containing SBA-15 materials has been tested for the heterogeneous Fenton degradation of phenolic aqueous solutions. The catalytic performance has beta monitored in terms of phenol conversion, whereas the catalytic stability was evaluated by catalyst recycle. The influence of concentration of hydrogen peroxide, catalyst loading, catalyst prepared with different Fe/Si molar ratios in the gel and pH values of the solution on phenol conversion has been studied. Achieving a good catalytic performance accompanied with a noteworthy stability, Fe-SBA-15 materials prepared by this method are shown as the successful catalyst for degradation of phenolic aqueous solutions by Fenton process.展开更多
CO_(2)hydrogenation has been considered to be a highly promising route for the production of high-value olefins(HVOs)while also mitigating CO_(2)emissions.However,it is challenging to achieve high selectivity and main...CO_(2)hydrogenation has been considered to be a highly promising route for the production of high-value olefins(HVOs)while also mitigating CO_(2)emissions.However,it is challenging to achieve high selectivity and maintain stable performance for HVOs(ethylene,propylene,and linear a-olefins)over a prolonged reaction time due to the difficulty in precise control of carbon coupling and rapid catalyst deactivation.Herein,we present a selective Ba and Na co-modified Fe catalyst enriched with Fe_(5)C_(2)and Fe_(3)C active sites that can boost HVO synthesis with up to 66.1%selectivity at an average CO_(2)conversion of 38%for over 500 h.Compared to traditional NaFe catalyst,the combined effect of Ba and Na additives in the NaBaFe-0.5 catalyst suppressed excess oxidation of FeCxsites by H_(2)O.The absence of Fe3O4phase in the spent NaBaFe-0.5 catalyst reflects the stabilization effect of the co-modifiers on the FeCxsites.This study provides a strategy to design Fe-based catalysts that can be scaled up for the stable synthesis of HVOs from CO_(2)hydrogenation.展开更多
Methane partial oxidation to methanol (MPOM) using dielectric barrier discharge over a Fe2O3-CuO/γ-Al2O3 catalyst was performed.The multicomponent catalyst was combined with plasma in two different configurations,i...Methane partial oxidation to methanol (MPOM) using dielectric barrier discharge over a Fe2O3-CuO/γ-Al2O3 catalyst was performed.The multicomponent catalyst was combined with plasma in two different configurations,i.e.,in-plasma catalysis (IPC) and post-plasma catalysis (PPC).It was found that the catalytic performance of the catalysts for MPOM was strongly dependent on the hybrid configuration.A better synergistic performance of plasma and catalysis was achieved in the IPC configuration,but the catalysts packed in the discharge zone showed lower stability than those connected to the discharge zone in sequence.Active species,such as ozone,atomic oxygen and methyl radicals,were produced from the plasma-catalysis process,and made a major contribution to methanol synthesis.These active species were identified by the means of in situ optical emission spectra,ozone measurement and FT-IR spectra.It was confirmed that the amount of active species in the IPC system was greater than that in the PPC system.The results of TG,XRD,and N2 adsorption-desorption revealed that carbon deposition on the spent catalyst surface was responsible for the catalyst deactivation in the IPC configuration.展开更多
Porous Pt thin films were prepared on carbon papers by a single-step ultra-high dc magnetron sputtering method to obtain ideal electrodes for proton exchange membrane fuel cells.The platinum loading of the electrocata...Porous Pt thin films were prepared on carbon papers by a single-step ultra-high dc magnetron sputtering method to obtain ideal electrodes for proton exchange membrane fuel cells.The platinum loading of the electrocatalyst layer is controlled at about 0.1 mg·cm^(-2).Structural characteristics and catalytic activities of the films were analyzed by scanning electron microscopy,atomic force microscopy,X-ray diffraction,cyclic voltammetry,and stress durability testing methods.The effect of treatment conditions of a substrate on the structural and performance characteristics of the catalytic films was shown as well.Films produced on acid-treated carbon papers at the argon pressure of 0.01 mbar possessed a homogeneous,highly developed surface along with a porous structure.Compared to Pt/TCPW(Toray carbon papers soaked in ultrapure water)electrodes,the film obtained on the acid-treated substrate had a larger electrochemical surface area(163.33 m^(2)·g^(-1))and exhibited better catalytic stability and durability due to a porous structure as a result of Pt particle accumulation.展开更多
The catalytic activity of polycobaltprotoporphyrin(PCoPP)was compared with adsorbed cobaltprotoporphyrin monolayer.The results have shown that PCoPP film shows higher catalytic activity and stability than monolayer on...The catalytic activity of polycobaltprotoporphyrin(PCoPP)was compared with adsorbed cobaltprotoporphyrin monolayer.The results have shown that PCoPP film shows higher catalytic activity and stability than monolayer on glass carbon electrode in both alkaline and acid solution. Catalytic activity of PCoPP goes through a maximum with increase of film thickness.A model was proposed to explain such dependence.The effect of film thickness and solution pH on the stability of PCoPP film was studied.展开更多
Silicoaluminophosphates (SAPOs) with different pore structures were synthesized through the implementation of polyethylene glycol (PEG) as a mesopores impregnation agent. Using PEGs with different molecular weigh...Silicoaluminophosphates (SAPOs) with different pore structures were synthesized through the implementation of polyethylene glycol (PEG) as a mesopores impregnation agent. Using PEGs with different molecular weights (MWs) and concentrations in the synthesis precursor, several samples were synthesized and characterized. Applying a PEG capping agent to the precursors led to the formation of tuned mesopores within the microporous matrix of the SAPO. The effects of the PEG molecular weight and PEG/Al molar ratio were investigated to maximize the efficiency of the catalyst in the methanol-to-olefin (MTO) process. Using PEG with a MW of 6000 resulted in the formation of both Zeolite Rho and chabazite structural frameworks (i.e., DNL-6 and SAPO-34). Pure SAPO-34 samples were successfully prepared using PEG with a MW of 4000. Our results showed that the PEG concentrations affect the porosity and acidity of the synthesized materials. Furthermore, the SAPO-34 sample synthesized with PEG (MW of 4000) and a PEG/Al molar ratio of 0.0125 showed a superior catalytic stability in the MTO reaction owing to the tuned bi-modal porosity and tailored acidity pattern. Finally, through reactivation experiments, it was found that the catalyst is stable even after several regeneration cycles.展开更多
HZSM-5, Al_2O_3, TiO_2 and SiO_2 supported CeO_2-ZrO_2-CrO_x catalysts were prepared by deposition-precipitation method and tested for deep catalytic oxidation of 1,2-dichloroethane(DCE), as one of the common chlori...HZSM-5, Al_2O_3, TiO_2 and SiO_2 supported CeO_2-ZrO_2-CrO_x catalysts were prepared by deposition-precipitation method and tested for deep catalytic oxidation of 1,2-dichloroethane(DCE), as one of the common chlorinated organic pollutants. All the catalysts were characterized by means of N_2 adsorption-desorption, X-ray photoelectron spectroscopy(XPS), ammonia-temperatureprogrammed desorption(NH_3-TPD) and hydrogen temperature-programmed reduction(H2-TPR). The characterization results revealed that there was strongly synergistic effect between the oxidizability of CZCr species and the acidity of supports, which obviously promoted the catalytic activity for DCE degradation. 20% CZCr/HZSM-5 showed the highest activity and good durability during the long-term continuous test. The catalytic activity decreased in the order: 20%CZCr/HZSM-5〉CZCr〉20%CZCr/TiO_2〉20%CZCr/Al_2O_3〉20%CZCr/SiO_2.展开更多
Herein, lanthanum was incorporated via hydrothermal synthesis into a MCM-41 framework structure with La/Si molar ratios from 0.01 to 0.1. Samples of NiO supported on LaMCM-41 were prepared using the impregnation metho...Herein, lanthanum was incorporated via hydrothermal synthesis into a MCM-41 framework structure with La/Si molar ratios from 0.01 to 0.1. Samples of NiO supported on LaMCM-41 were prepared using the impregnation method. The catalyst performance was evaluated using a fixed bed CO methanation reactor. A Ni/LaMCM-41 catalyst with La/Si = 0.1 shows the best catalytic performance with a CO conversion of almost 100% and a CH4 selectivity of 89.5% at 250 ℃ under a pressure of 1.5 MPa and at an airspeed of 36,000 mL/(g·h). Compared with Ni-La/MCM-41(La/Si = 0.1) and Ni/MCM-41 prepared via the impregnation method, Ni/LaMCM-41(La/Si = 0.1) shows a higher CO conversion and CH4 selectivity.In a 100 h stability test, the Ni/LaMCM-41(La/Si = 0.1) catalyst shows excellent stability; furthermore, the CO conversion is always greater than 98.0%, which is significantly better than the results for Ni/MCM-41.We experimentally demonstrate that elemental La enters the framework of MCM-41. The Ni/LaMCM-41 catalyst performs well because the La reduces the average particle size of the NiO particles and enhances the interaction between NiO and MCM-41; moreover, the introduction of La significantly inhibits the sintering of the catalyst and the formation of carbon deposits.展开更多
A new class of rhodium complexes with high catalytic activity as well as excellent stability, which was used as catalyst for carbonylation of methanol to acetic acid, is reported. It contains free donor (namely un-coo...A new class of rhodium complexes with high catalytic activity as well as excellent stability, which was used as catalyst for carbonylation of methanol to acetic acid, is reported. It contains free donor (namely un-coordinated donor) atoms which enable to improve its stability by intramolecular substitution reaction. Its synthesis, characteristic and catalytic reaction were discussed here.展开更多
基金the National Natural Science Foundation of China(2040101550574082)
文摘An iron-containing SBA-15(Fe-SBA-15) has been synthesized via one-pot hydrothermal method under weak acidic conditions. A series of characterizations show nanocomposite materials of iron particles supported over mesostructured materials. The catalytic activity of these iron-containing SBA-15 materials has been tested for the heterogeneous Fenton degradation of phenolic aqueous solutions. The catalytic performance has beta monitored in terms of phenol conversion, whereas the catalytic stability was evaluated by catalyst recycle. The influence of concentration of hydrogen peroxide, catalyst loading, catalyst prepared with different Fe/Si molar ratios in the gel and pH values of the solution on phenol conversion has been studied. Achieving a good catalytic performance accompanied with a noteworthy stability, Fe-SBA-15 materials prepared by this method are shown as the successful catalyst for degradation of phenolic aqueous solutions by Fenton process.
基金supported by the National Natural Science Foundation of China(21802138,21773234 and 22078315)the‘‘Transformational Technologies for Clean Energy and Demonstration’’,Strategic Priority Research Program of the Chinese Academy of Sciences(XDA 21090203)+3 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2020189)the Natural Science Foundation of Liaoning Province(2022-MS-027)the Youth Science and Technology Star Project Support Program of Dalian City(2021RQ123),DICP(Grant:DICP I202138)the University of Chinese Academy of Sciences(UCAS)for UCAS Scholarship。
文摘CO_(2)hydrogenation has been considered to be a highly promising route for the production of high-value olefins(HVOs)while also mitigating CO_(2)emissions.However,it is challenging to achieve high selectivity and maintain stable performance for HVOs(ethylene,propylene,and linear a-olefins)over a prolonged reaction time due to the difficulty in precise control of carbon coupling and rapid catalyst deactivation.Herein,we present a selective Ba and Na co-modified Fe catalyst enriched with Fe_(5)C_(2)and Fe_(3)C active sites that can boost HVO synthesis with up to 66.1%selectivity at an average CO_(2)conversion of 38%for over 500 h.Compared to traditional NaFe catalyst,the combined effect of Ba and Na additives in the NaBaFe-0.5 catalyst suppressed excess oxidation of FeCxsites by H_(2)O.The absence of Fe3O4phase in the spent NaBaFe-0.5 catalyst reflects the stabilization effect of the co-modifiers on the FeCxsites.This study provides a strategy to design Fe-based catalysts that can be scaled up for the stable synthesis of HVOs from CO_(2)hydrogenation.
基金supported by the National Natural Science Foundation of China(No. 20836008 and U0633003)the Zhejiang Provincial Natural Science Foundation of China(No. Y5080192)+3 种基金the Project of Science and Technology Department of Zhejiang Province of China(2007C13061)MOST Project of China(No. 2007AA06Z339,No. 2008BAC32B06 and No. 2007AA06A409)the Open Project Program of Key Laboratory of Non-point Sources Pollution Controlthe Ministry of Agriculture of the People’s Republic of China and Science Foundation of Chinese University
文摘Methane partial oxidation to methanol (MPOM) using dielectric barrier discharge over a Fe2O3-CuO/γ-Al2O3 catalyst was performed.The multicomponent catalyst was combined with plasma in two different configurations,i.e.,in-plasma catalysis (IPC) and post-plasma catalysis (PPC).It was found that the catalytic performance of the catalysts for MPOM was strongly dependent on the hybrid configuration.A better synergistic performance of plasma and catalysis was achieved in the IPC configuration,but the catalysts packed in the discharge zone showed lower stability than those connected to the discharge zone in sequence.Active species,such as ozone,atomic oxygen and methyl radicals,were produced from the plasma-catalysis process,and made a major contribution to methanol synthesis.These active species were identified by the means of in situ optical emission spectra,ozone measurement and FT-IR spectra.It was confirmed that the amount of active species in the IPC system was greater than that in the PPC system.The results of TG,XRD,and N2 adsorption-desorption revealed that carbon deposition on the spent catalyst surface was responsible for the catalyst deactivation in the IPC configuration.
基金Funded by the Doctoral Fund of Southwest University of Science and Technology(Nos.19zx7131 and 18zx7132)the Applied Fundamental Research Projects of Science and Technology Department of Sichuan Province(No.2020YJ0333)+1 种基金the Science and Technology on Plasma Physics Laboratory:6142A04180405Science and Technology on Plasma Physics Laboratory:ZY2018-07。
文摘Porous Pt thin films were prepared on carbon papers by a single-step ultra-high dc magnetron sputtering method to obtain ideal electrodes for proton exchange membrane fuel cells.The platinum loading of the electrocatalyst layer is controlled at about 0.1 mg·cm^(-2).Structural characteristics and catalytic activities of the films were analyzed by scanning electron microscopy,atomic force microscopy,X-ray diffraction,cyclic voltammetry,and stress durability testing methods.The effect of treatment conditions of a substrate on the structural and performance characteristics of the catalytic films was shown as well.Films produced on acid-treated carbon papers at the argon pressure of 0.01 mbar possessed a homogeneous,highly developed surface along with a porous structure.Compared to Pt/TCPW(Toray carbon papers soaked in ultrapure water)electrodes,the film obtained on the acid-treated substrate had a larger electrochemical surface area(163.33 m^(2)·g^(-1))and exhibited better catalytic stability and durability due to a porous structure as a result of Pt particle accumulation.
文摘The catalytic activity of polycobaltprotoporphyrin(PCoPP)was compared with adsorbed cobaltprotoporphyrin monolayer.The results have shown that PCoPP film shows higher catalytic activity and stability than monolayer on glass carbon electrode in both alkaline and acid solution. Catalytic activity of PCoPP goes through a maximum with increase of film thickness.A model was proposed to explain such dependence.The effect of film thickness and solution pH on the stability of PCoPP film was studied.
文摘Silicoaluminophosphates (SAPOs) with different pore structures were synthesized through the implementation of polyethylene glycol (PEG) as a mesopores impregnation agent. Using PEGs with different molecular weights (MWs) and concentrations in the synthesis precursor, several samples were synthesized and characterized. Applying a PEG capping agent to the precursors led to the formation of tuned mesopores within the microporous matrix of the SAPO. The effects of the PEG molecular weight and PEG/Al molar ratio were investigated to maximize the efficiency of the catalyst in the methanol-to-olefin (MTO) process. Using PEG with a MW of 6000 resulted in the formation of both Zeolite Rho and chabazite structural frameworks (i.e., DNL-6 and SAPO-34). Pure SAPO-34 samples were successfully prepared using PEG with a MW of 4000. Our results showed that the PEG concentrations affect the porosity and acidity of the synthesized materials. Furthermore, the SAPO-34 sample synthesized with PEG (MW of 4000) and a PEG/Al molar ratio of 0.0125 showed a superior catalytic stability in the MTO reaction owing to the tuned bi-modal porosity and tailored acidity pattern. Finally, through reactivation experiments, it was found that the catalyst is stable even after several regeneration cycles.
基金Project supports from National Nature Science Foundation of China(21177110)
文摘HZSM-5, Al_2O_3, TiO_2 and SiO_2 supported CeO_2-ZrO_2-CrO_x catalysts were prepared by deposition-precipitation method and tested for deep catalytic oxidation of 1,2-dichloroethane(DCE), as one of the common chlorinated organic pollutants. All the catalysts were characterized by means of N_2 adsorption-desorption, X-ray photoelectron spectroscopy(XPS), ammonia-temperatureprogrammed desorption(NH_3-TPD) and hydrogen temperature-programmed reduction(H2-TPR). The characterization results revealed that there was strongly synergistic effect between the oxidizability of CZCr species and the acidity of supports, which obviously promoted the catalytic activity for DCE degradation. 20% CZCr/HZSM-5 showed the highest activity and good durability during the long-term continuous test. The catalytic activity decreased in the order: 20%CZCr/HZSM-5〉CZCr〉20%CZCr/TiO_2〉20%CZCr/Al_2O_3〉20%CZCr/SiO_2.
基金Project supported by the National Natural Science Foundation of China(U1203293)the Doctor Foundation of Bingtuan(2013BB010)the Foundation of Young Scientist in Shihezi University(2013ZRKXJQ03)
文摘Herein, lanthanum was incorporated via hydrothermal synthesis into a MCM-41 framework structure with La/Si molar ratios from 0.01 to 0.1. Samples of NiO supported on LaMCM-41 were prepared using the impregnation method. The catalyst performance was evaluated using a fixed bed CO methanation reactor. A Ni/LaMCM-41 catalyst with La/Si = 0.1 shows the best catalytic performance with a CO conversion of almost 100% and a CH4 selectivity of 89.5% at 250 ℃ under a pressure of 1.5 MPa and at an airspeed of 36,000 mL/(g·h). Compared with Ni-La/MCM-41(La/Si = 0.1) and Ni/MCM-41 prepared via the impregnation method, Ni/LaMCM-41(La/Si = 0.1) shows a higher CO conversion and CH4 selectivity.In a 100 h stability test, the Ni/LaMCM-41(La/Si = 0.1) catalyst shows excellent stability; furthermore, the CO conversion is always greater than 98.0%, which is significantly better than the results for Ni/MCM-41.We experimentally demonstrate that elemental La enters the framework of MCM-41. The Ni/LaMCM-41 catalyst performs well because the La reduces the average particle size of the NiO particles and enhances the interaction between NiO and MCM-41; moreover, the introduction of La significantly inhibits the sintering of the catalyst and the formation of carbon deposits.
基金Project (No. 29974035) supported by the National Natural Science Foundation of China
文摘A new class of rhodium complexes with high catalytic activity as well as excellent stability, which was used as catalyst for carbonylation of methanol to acetic acid, is reported. It contains free donor (namely un-coordinated donor) atoms which enable to improve its stability by intramolecular substitution reaction. Its synthesis, characteristic and catalytic reaction were discussed here.