A silica-supported cobalt catalyst was prepared by hydrogen dielectric-barrier dis- charge （H2-DBD） plasma. Compared to thermal hydrogen reduction, H2-DBD plasma treatment can not only fully decompose the cobalt pre...A silica-supported cobalt catalyst was prepared by hydrogen dielectric-barrier dis- charge （H2-DBD） plasma. Compared to thermal hydrogen reduction, H2-DBD plasma treatment can not only fully decompose the cobalt precursor but also partially reduce the cobalt oxides at lower temperature and with less time. The effect of the discharge atmosphere on the property of the plasma-prepared catalyst and the Fischer-Tropsch synthesis activity was studied. The re- sults indicate that H2-DBD plasma treatment is a promising alternative for preparing Co/SiO2 catalysts from the viewpoint of energy savings and efficiency.展开更多
A new pulsed chemical vapor deposition（PCVD） process has been developed to fabricate iron（Fe） and iron carbide(Fe1-xCx) thin films at low temperature range from 150 ℃ to 230 ℃.The process employs bis（1,4-di-ter...A new pulsed chemical vapor deposition（PCVD） process has been developed to fabricate iron（Fe） and iron carbide(Fe1-xCx) thin films at low temperature range from 150 ℃ to 230 ℃.The process employs bis（1,4-di-tert-butyl-1,3-diazabutadienyl）iron（Ⅱ） as iron source and hydrogen gas or hydrogen plasma as the coreactant.The films deposited with hydrogen gas are demonstrated polycrystalline with body-centered cubic Fe.However,for the films deposited with hydrogen plasma,the amorphous phase of iron carbide is obtained.The influence of the deposition temperature on iron and iron carbide characteristics have been investigated.展开更多
Hydrogen dielectric-barrier discharge (H<sub>2</sub>-DBD) plasma was successfully used to prepare carbon nanotubes (CNTs)-supported cobalt (Co) catalyst. The H<sub>2</sub>-DBD plasma treatment ...Hydrogen dielectric-barrier discharge (H<sub>2</sub>-DBD) plasma was successfully used to prepare carbon nanotubes (CNTs)-supported cobalt (Co) catalyst. The H<sub>2</sub>-DBD plasma treatment simultaneously decomposed and reduced the cobalt precursor at a lower temperature and in a shorter time than the conventional method (calcination and hydrogen reduction). It is considered that the H<sub>2</sub>-DBD plasma method can remarkably decrease the amount of energy input compared to traditional methods used to prepare the Co-based catalyst in Fischer-Tropsch synthesis (FTS). Results showed that the Co catalyst prepared by H<sub>2</sub>-DBD plasma had an equivalent catalytic performance for FTS as that prepared using the conventional method in calcination and hydrogen reduction, thereby determining that H<sub>2</sub>-DBD plasma was an effective alternative treatment for preparing the Co/CNTs catalyst for FTS. This technology will provide a new strategy for preparing catalysts in other catalysis processes.展开更多
Methane was decomposed to hydrogen and carbon nanotubes (CNTs) by microwave plasma, using Fe/Si catalyst activated by biased (—150 V) hydrogen plasma for various treatment times. Upon exposure to biased hydrogen plas...Methane was decomposed to hydrogen and carbon nanotubes (CNTs) by microwave plasma, using Fe/Si catalyst activated by biased (—150 V) hydrogen plasma for various treatment times. Upon exposure to biased hydrogen plasma, the catalyst surface becomes lumpy within 1 min, coheres between 5 and 10 min and forms particles after 20 min. The methane conversion increased up to 93% over the treatment time of 5 min. The hydrogen yield showed as similar tendency as the methane conversion and kept 83% at treatment time of 5 min. The treatment time up to 1 min increased the amount of deposited carbon, and after treatment time of 5 min it dropped;then again after treatment time of 20 min, it increased to reach a maximum value of 22 gc/gcat. Deposited carbon was found to be consisted of carbon nanotubes. It grew vertically on the catalyst surface and reached a maximum length of 30.7 nm after treatment time of 10 min. Multiple types of CNTs were present, and the CNT diameters decreased with increasing plasma treatment time.展开更多
This study aimed to discuss the removal of hydrogen sulfide （H2S） with non-thermal plasma produced by a multilayer tubular dielectric barrier discharge reactor,which is useful in the field of plasma environmental ap...This study aimed to discuss the removal of hydrogen sulfide （H2S） with non-thermal plasma produced by a multilayer tubular dielectric barrier discharge reactor,which is useful in the field of plasma environmental applications.We explored the influence of various factors upon H2S removal efficiency （ηH2S） and energy yield （Ey）,such as specific energy density （SED）,initial concentration,gas flow velocity and the reactor configuration.The study showed that we can achieve ηH2S of 91% and the best Ey of 3100 mg kWh-1 when we set the SED,gas flow velocity,initial H2S concentration and layers of quartz tubes at 33.2 J 1-1,8.0 m s-1,30 mg m-3 and five layers,correspondingly.The average rate constant for the decomposition of hydrogen sulfide was 0.206 g m-3 s-1.In addition,we also presented the optimized working conditions,byproduct analysis and decomposition mechanism.展开更多
High current hydrogen molecular ion beam is obtained with a specially designed stainless steel liner permanent magnet2.45-GHz electron–cyclotron resonance（ECR） ion source（PMECR II） at Peking University（PKU）. To...High current hydrogen molecular ion beam is obtained with a specially designed stainless steel liner permanent magnet2.45-GHz electron–cyclotron resonance（ECR） ion source（PMECR II） at Peking University（PKU）. To further understand the physics of the hydrogen generation process inside a plasma chamber, theoretical and experimental investigations on the liner material of the plasma chamber in different running conditions are carried out. Several kinds of materials, stainless steel（SS）, tantalum（Ta）, quartz, and aluminum（Al） are selected in our study. Experimental results show that stainless steel and tantalum are much better than others in H~＋_2 generation. During the experiment, an increasing trend in H~＋_2 fraction is observed with stainless steel liner after O_2 discharge inside the ion source. Surface analyses show that the roughness change on the surface after O_2 discharge may be responsible for this phenomenon. After these studies, the pure current of H~＋_2 ions can reach 42.3 mA with a fraction of 52.9%. More details are presented in this paper.展开更多
A novel glow discharge plasma solid-state reduction route was developed to synthesize molybdophosphoric heteropoly blues(MB). The glow discharge plasma played a role of activating hydrogen mole-cules and generated a l...A novel glow discharge plasma solid-state reduction route was developed to synthesize molybdophosphoric heteropoly blues(MB). The glow discharge plasma played a role of activating hydrogen mole-cules and generated a lot of active species which rapidly induced molybdophosphoric heteropoly acid(PMo12) to form four-electron MB within several minutes. Analyses of the heteropoly blues via UV-Vis, FTIR, XRD and Py-IR confirmed that the materials retained not only the similar Keggin structures of their oxidized parents, but also exhibited more surface acidity due to protonation.展开更多
基金supported by National Natural Science Foundation of China(No.21076151)
文摘A silica-supported cobalt catalyst was prepared by hydrogen dielectric-barrier dis- charge （H2-DBD） plasma. Compared to thermal hydrogen reduction, H2-DBD plasma treatment can not only fully decompose the cobalt precursor but also partially reduce the cobalt oxides at lower temperature and with less time. The effect of the discharge atmosphere on the property of the plasma-prepared catalyst and the Fischer-Tropsch synthesis activity was studied. The re- sults indicate that H2-DBD plasma treatment is a promising alternative for preparing Co/SiO2 catalysts from the viewpoint of energy savings and efficiency.
基金financially supported by National Natural Science Foundation of China(No.11775028)Collaborative Innovation Center of Green Printing&Publishing Technology(No.15208)Beijing Institute of Graphic Communication Project(Nos.Ea201801 04190119001-020 and 12000400001)
文摘A new pulsed chemical vapor deposition（PCVD） process has been developed to fabricate iron（Fe） and iron carbide(Fe1-xCx) thin films at low temperature range from 150 ℃ to 230 ℃.The process employs bis（1,4-di-tert-butyl-1,3-diazabutadienyl）iron（Ⅱ） as iron source and hydrogen gas or hydrogen plasma as the coreactant.The films deposited with hydrogen gas are demonstrated polycrystalline with body-centered cubic Fe.However,for the films deposited with hydrogen plasma,the amorphous phase of iron carbide is obtained.The influence of the deposition temperature on iron and iron carbide characteristics have been investigated.
基金Supported by the National Natural Science Foundation of China (No.21506154)the program for New Century Excellent Talents in University of Ministry of Education of China (NCET-06-0239)
文摘Hydrogen dielectric-barrier discharge (H<sub>2</sub>-DBD) plasma was successfully used to prepare carbon nanotubes (CNTs)-supported cobalt (Co) catalyst. The H<sub>2</sub>-DBD plasma treatment simultaneously decomposed and reduced the cobalt precursor at a lower temperature and in a shorter time than the conventional method (calcination and hydrogen reduction). It is considered that the H<sub>2</sub>-DBD plasma method can remarkably decrease the amount of energy input compared to traditional methods used to prepare the Co-based catalyst in Fischer-Tropsch synthesis (FTS). Results showed that the Co catalyst prepared by H<sub>2</sub>-DBD plasma had an equivalent catalytic performance for FTS as that prepared using the conventional method in calcination and hydrogen reduction, thereby determining that H<sub>2</sub>-DBD plasma was an effective alternative treatment for preparing the Co/CNTs catalyst for FTS. This technology will provide a new strategy for preparing catalysts in other catalysis processes.
文摘Methane was decomposed to hydrogen and carbon nanotubes (CNTs) by microwave plasma, using Fe/Si catalyst activated by biased (—150 V) hydrogen plasma for various treatment times. Upon exposure to biased hydrogen plasma, the catalyst surface becomes lumpy within 1 min, coheres between 5 and 10 min and forms particles after 20 min. The methane conversion increased up to 93% over the treatment time of 5 min. The hydrogen yield showed as similar tendency as the methane conversion and kept 83% at treatment time of 5 min. The treatment time up to 1 min increased the amount of deposited carbon, and after treatment time of 5 min it dropped;then again after treatment time of 20 min, it increased to reach a maximum value of 22 gc/gcat. Deposited carbon was found to be consisted of carbon nanotubes. It grew vertically on the catalyst surface and reached a maximum length of 30.7 nm after treatment time of 10 min. Multiple types of CNTs were present, and the CNT diameters decreased with increasing plasma treatment time.
基金Supported by programs of Research on the Technology and Equipment of Gaseous Pollutant Removal from the Emission of Household Garbage(15DZ12055904)Jointly Decomposition of Odorous Compounds by Dielectric Combined with Excimer Ultraviolet Emission(21577023)
文摘This study aimed to discuss the removal of hydrogen sulfide （H2S） with non-thermal plasma produced by a multilayer tubular dielectric barrier discharge reactor,which is useful in the field of plasma environmental applications.We explored the influence of various factors upon H2S removal efficiency （ηH2S） and energy yield （Ey）,such as specific energy density （SED）,initial concentration,gas flow velocity and the reactor configuration.The study showed that we can achieve ηH2S of 91% and the best Ey of 3100 mg kWh-1 when we set the SED,gas flow velocity,initial H2S concentration and layers of quartz tubes at 33.2 J 1-1,8.0 m s-1,30 mg m-3 and five layers,correspondingly.The average rate constant for the decomposition of hydrogen sulfide was 0.206 g m-3 s-1.In addition,we also presented the optimized working conditions,byproduct analysis and decomposition mechanism.
基金supported by the National Natural Science Foundation of China(Grant Nos.11175009 and 11575013)
文摘High current hydrogen molecular ion beam is obtained with a specially designed stainless steel liner permanent magnet2.45-GHz electron–cyclotron resonance（ECR） ion source（PMECR II） at Peking University（PKU）. To further understand the physics of the hydrogen generation process inside a plasma chamber, theoretical and experimental investigations on the liner material of the plasma chamber in different running conditions are carried out. Several kinds of materials, stainless steel（SS）, tantalum（Ta）, quartz, and aluminum（Al） are selected in our study. Experimental results show that stainless steel and tantalum are much better than others in H~＋_2 generation. During the experiment, an increasing trend in H~＋_2 fraction is observed with stainless steel liner after O_2 discharge inside the ion source. Surface analyses show that the roughness change on the surface after O_2 discharge may be responsible for this phenomenon. After these studies, the pure current of H~＋_2 ions can reach 42.3 mA with a fraction of 52.9%. More details are presented in this paper.
文摘A novel glow discharge plasma solid-state reduction route was developed to synthesize molybdophosphoric heteropoly blues(MB). The glow discharge plasma played a role of activating hydrogen mole-cules and generated a lot of active species which rapidly induced molybdophosphoric heteropoly acid(PMo12) to form four-electron MB within several minutes. Analyses of the heteropoly blues via UV-Vis, FTIR, XRD and Py-IR confirmed that the materials retained not only the similar Keggin structures of their oxidized parents, but also exhibited more surface acidity due to protonation.
