The paper briefly dealt with relieving toxic effects of La on high aquatic plant-Hydrocharis dubia B L. Backer growing in the solution containing different concentration of Ni. The results show that La can relieve the...The paper briefly dealt with relieving toxic effects of La on high aquatic plant-Hydrocharis dubia B L. Backer growing in the solution containing different concentration of Ni. The results show that La can relieve the reduction of chlorophyll content, the accumulation of MDA(malondiadehyde) and the elevation of relative membrane penetrability (RMP). After adding 10 mg . L-1 La to the solution, the activities of SOD and CAT in the leaves of Hydrocharis dubia B L. Backer increases compared with those of the single treatment of Ni, while the activity of POD decreases. It reveals that la enhances the abilities of scavenging the activated oxygen in the plant and alleviates the damage to the membranes. The soluble protein content with Ni and La compound treatment is higher than that of single Ni does, and proline content is contrary to the soluble protein content. So La improves the resistance of Hydrocharis dubia B. L. Backer to the stress of Ni. However, La can aggravate the damage to the cells under the extremely high concentration of Ni treatment.展开更多
A new process for electrolytic production of a perfluorinated compound, （CF3）3N, using lanthanum nickel oxide-coated Ni sheet anode in the （CH3）4NF· 4.0HF melt at room temperature, was developed. Thin films o...A new process for electrolytic production of a perfluorinated compound, （CF3）3N, using lanthanum nickel oxide-coated Ni sheet anode in the （CH3）4NF· 4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone（PVP）. The main components of the thin films were La2O3, LaNiO3, and La2NiO4 at 500, 750 and 1000℃, respectively. The anode performance in the （CH3）4NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO3-coated Ni sheet anode gives the best anode performance. The potential of LaNiO3-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm^-2 in the （CH3）4NF·4.0HF melt for 100 h. This is because LaNiO3 and NiF3 and/or Ni2F5, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of （CF3）3N （21.4%） was obtained at 20 mA·cm^-2 in （CH3）4NF·4.0HF melt using the LaNiO3-coated Ni sheet.展开更多
Lanthanum and nitrogen co-doped SrTiO_3 was prepared by a mechanochemical reaction using SrTiO_3, urea and La_2O_3 as the raw materials. The samples were characterized by X-ray diffraction, X-ray photoelectron spectro...Lanthanum and nitrogen co-doped SrTiO_3 was prepared by a mechanochemical reaction using SrTiO_3, urea and La_2O_3 as the raw materials. The samples were characterized by X-ray diffraction, X-ray photoelectron spectrometer, transmission electron microscopy, and nitrogen adsorption-desorption isotherm measurements. Lanthanum doping could increase the doping content of nitrogen in the sample. The sample prepared with 0.2 mol% La_2O_3, 22 mol% urea and 77.8 mol% SrTiO_3 by mechanochemical reaction, which has nearly the same nitrogen and lanthanum doping fractions, exhibited high photocatalytic activities. Under the irradiation of light with wavelength larger than 400, and 290 nm, the photocatalytic activity of nitrogen and lanthanum co-doped SrTiO_3 were 2.6 and 2 times greater than that of pure SrTiO_3.展开更多
In the current work, LaNiO3 perovskite was synthesized using the polymeric precursor method. The materials were thermally treated at 300°C for 2 hours, subsequently supported on alumina or zirconia and finally ca...In the current work, LaNiO3 perovskite was synthesized using the polymeric precursor method. The materials were thermally treated at 300°C for 2 hours, subsequently supported on alumina or zirconia and finally calcined at 800°C for 4 hours. The resulting samples were characterized by X-ray diffraction, thermogravimetry, BET surface area and thermo-programmed reduction. Steam reforming reactions were carried out at 750°C and 6 bar during 4 hours using a pilot reactor under a H2O:CH4 ratio of 2.5. The mass of catalysts was about 5.7 g. X-ray diffraction patterns confirmed the formation of the perovskite structure in all samples prepared. The results also showed that lanthanum nickelate was more efficient when supported on alumina than zirconia. Finally, it was observed that the methane conversion was approximately 94% and the selectivity to hydrogen was about 70%. In all cases low selectivity to CO and CO2 was verified.展开更多
La,Ce co-doped ZnO nanorods(ZnLC)were synthesized through a one-step solvothermal route.The photocatalysts were characterized by X-ray diffraction,Raman spectroscopy,field-emission scanning electron microscopy,energy ...La,Ce co-doped ZnO nanorods(ZnLC)were synthesized through a one-step solvothermal route.The photocatalysts were characterized by X-ray diffraction,Raman spectroscopy,field-emission scanning electron microscopy,energy dispersive X-ray,transmission electron microscopy,UV-vis diffuse reflectance spectroscopy and photo luminescence spectroscopy.The La and Ce doping enhanced the visible light absorption ability of ZnLC and a red shift was detected for ZnLC.Under simulated solar light irradiation,the ZnO doped with 3 at%La and 1 at%Ce(ZnLC1)degrades methylene blue(MB)more effectively than those of pure ZnO,La-doped ZnO(ZnL)and commercially available ZnO.The improved photocatalytic performance of ZnLC1 can be attributed to the high charge separation efficiency as demonstrated by the photoluminescence spectra.Additionally,the photocatalytic experiments reveal that several parameters have their own impact on the MB degradation.Using a variety of radical scavengers,it is discovered that superoxide anion radical plays a crucial role in the degradation of MB.The ZnLC1 is also reused several times without noticeable decrease of photoactivity,indicating that it has a substantial potential for environmental remediation applications.展开更多
La modified Ni/T-Al2O3 catalysts prepared by co-precipitation method using NaOH-Na2CO3 as a precipitator show high activity and selectivity for the partial oxidation of methane （POM）. Meanwhile, the addition of La i...La modified Ni/T-Al2O3 catalysts prepared by co-precipitation method using NaOH-Na2CO3 as a precipitator show high activity and selectivity for the partial oxidation of methane （POM）. Meanwhile, the addition of La is beneficial for the formation of an active component and stability of support. We investigated some factors including calcining temperature, nickel content, and space velocity, which turned out to have a strong influence on catalytic activity and selectivity. By XRD and TPR, it is concluded that Ni^0 reduced from amorphous NiAl2O4 is the major active component for POM.展开更多
A series of perovskite-type complex oxides LaNi1-xRuxO3 were prepared and studied by means of XRD. The effects of some factors on th complex oxides were discussed. Each kind of those perovskite-type complex oxides was...A series of perovskite-type complex oxides LaNi1-xRuxO3 were prepared and studied by means of XRD. The effects of some factors on th complex oxides were discussed. Each kind of those perovskite-type complex oxides was used to prepare cathode by composite-electroplating technique. The cathodes were electrochemically charactrized. The results show that these novel cathode exhibit high activities and excellent stabilities during long-term continuous electrolysis with some current interruptions.展开更多
Nanocrystalline nickel ferrites with substitution of Fe3+ by rare-earth La3+, according to the formula NiLaxFe2-xO4 (with x=0, 0.05, 0.1 and 0.15), were prepared by polyacrylamide gel method. Influences of the amount ...Nanocrystalline nickel ferrites with substitution of Fe3+ by rare-earth La3+, according to the formula NiLaxFe2-xO4 (with x=0, 0.05, 0.1 and 0.15), were prepared by polyacrylamide gel method. Influences of the amount of La3+ substitution on the structure and electromagnetic properties of NiLaxFe2-xO4 compounds were systematically investigated by DSC-TG, XRD, TEM and wave-guide method. XRD results indicated that the pure spinel-type crystal structure of the NiLaxFe2-xO4 (x=0 and 0.05) was obtained at 500 ℃. TEM results showed that the average particle sizes of NiFe2O4 and NiLa0.1Fe1.9O4 particles were about 10 and 15 nm, respectively. The complex permittivity and complex permeability was measured in the frequency range of 8.2～12.4 GHz. The results revealed that the nanocrystalline NiLaxFe2-xO4 had both dielectric loss and magnetic loss in the frequency range of 8.2～12.4 GHz. The tgδε and tgδm of NiLaxFe2-xO4 (with x=0 and 0.05) decreased with the increase of La3+ ions content, and some strong resonance peaks of the tgδε and tgδm of NiLaxFe2-xO4 (with x=0.1 and 0.15) appeared because of the secondary phases (LaFeO3) and more lattice defects.展开更多
A series of lanthanum containing Ni-base catalysts were prepared by citric acid complex method.Carbon nanotubes (CNT) were synthesized bY catalytic decomposing CH4 over these catalysts and characterized by XRD, TEM an...A series of lanthanum containing Ni-base catalysts were prepared by citric acid complex method.Carbon nanotubes (CNT) were synthesized bY catalytic decomposing CH4 over these catalysts and characterized by XRD, TEM and TGA.It is found that the addition of lanthanum can not increase the yield of carbon nanotube, but can make the diameter of carbon nanotube thinner and even.The more the lanthanum addsr, the thinner the diameter of CNTs becomes.With the CNTs prepared on Ni-Mg catalyst, the CNTs prepared on Ni-La-Mg catalyst has better crystallinity and thermal stability.展开更多
Designing highly active and stable electrocata-lysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a challenge for energy con-version and storage technology.In this work,a S and N co-doped g...Designing highly active and stable electrocata-lysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a challenge for energy con-version and storage technology.In this work,a S and N co-doped graphene supported cobalt–nickel sulfide composite catalyst(rGO@SN-CoNi_(2)S_(4))was synthesized simply via a one-step hydrothermal method.The as-synthesized CoNi_(2)S_(4)particles grew in a mosaic manner inside GO lamellae and were encapsulated with graphene.As a bifunctional catalyst,the r GO@SN-CoNi_(2)S_(4)exhibits excellent electrocatalytic performance under alkaline con-ditions,which only required the overpotential of 142.6 mV(vs.RHE)and 310 m V(vs.RHE)to deliver a current density of 10 mA·cm^(-2) for HER and OER,respectively.The good hydrophilicity of the r GO@SN,the pure phase of bimetallic structure,and the chemical coupling/interaction between the CoNi_(2)S_(4)and the rGO@SN are attributable to be the possible reasons responsible for the higher HER and OER catalytic activities.Additionally,the rGO@SN-CoNi_(2)S_(4)also shows a great potential for serving as an excellent cathode and anode electrolyzer during the water splitting process.展开更多
文摘The paper briefly dealt with relieving toxic effects of La on high aquatic plant-Hydrocharis dubia B L. Backer growing in the solution containing different concentration of Ni. The results show that La can relieve the reduction of chlorophyll content, the accumulation of MDA(malondiadehyde) and the elevation of relative membrane penetrability (RMP). After adding 10 mg . L-1 La to the solution, the activities of SOD and CAT in the leaves of Hydrocharis dubia B L. Backer increases compared with those of the single treatment of Ni, while the activity of POD decreases. It reveals that la enhances the abilities of scavenging the activated oxygen in the plant and alleviates the damage to the membranes. The soluble protein content with Ni and La compound treatment is higher than that of single Ni does, and proline content is contrary to the soluble protein content. So La improves the resistance of Hydrocharis dubia B. L. Backer to the stress of Ni. However, La can aggravate the damage to the cells under the extremely high concentration of Ni treatment.
文摘A new process for electrolytic production of a perfluorinated compound, （CF3）3N, using lanthanum nickel oxide-coated Ni sheet anode in the （CH3）4NF· 4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone（PVP）. The main components of the thin films were La2O3, LaNiO3, and La2NiO4 at 500, 750 and 1000℃, respectively. The anode performance in the （CH3）4NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO3-coated Ni sheet anode gives the best anode performance. The potential of LaNiO3-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm^-2 in the （CH3）4NF·4.0HF melt for 100 h. This is because LaNiO3 and NiF3 and/or Ni2F5, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of （CF3）3N （21.4%） was obtained at 20 mA·cm^-2 in （CH3）4NF·4.0HF melt using the LaNiO3-coated Ni sheet.
文摘Lanthanum and nitrogen co-doped SrTiO_3 was prepared by a mechanochemical reaction using SrTiO_3, urea and La_2O_3 as the raw materials. The samples were characterized by X-ray diffraction, X-ray photoelectron spectrometer, transmission electron microscopy, and nitrogen adsorption-desorption isotherm measurements. Lanthanum doping could increase the doping content of nitrogen in the sample. The sample prepared with 0.2 mol% La_2O_3, 22 mol% urea and 77.8 mol% SrTiO_3 by mechanochemical reaction, which has nearly the same nitrogen and lanthanum doping fractions, exhibited high photocatalytic activities. Under the irradiation of light with wavelength larger than 400, and 290 nm, the photocatalytic activity of nitrogen and lanthanum co-doped SrTiO_3 were 2.6 and 2 times greater than that of pure SrTiO_3.
基金The authors wish to acknowledge RECAT-Petrobras,Rede de Hidrogenio-MCTANP for their financial support and scholarship grants.
文摘In the current work, LaNiO3 perovskite was synthesized using the polymeric precursor method. The materials were thermally treated at 300°C for 2 hours, subsequently supported on alumina or zirconia and finally calcined at 800°C for 4 hours. The resulting samples were characterized by X-ray diffraction, thermogravimetry, BET surface area and thermo-programmed reduction. Steam reforming reactions were carried out at 750°C and 6 bar during 4 hours using a pilot reactor under a H2O:CH4 ratio of 2.5. The mass of catalysts was about 5.7 g. X-ray diffraction patterns confirmed the formation of the perovskite structure in all samples prepared. The results also showed that lanthanum nickelate was more efficient when supported on alumina than zirconia. Finally, it was observed that the methane conversion was approximately 94% and the selectivity to hydrogen was about 70%. In all cases low selectivity to CO and CO2 was verified.
文摘La,Ce co-doped ZnO nanorods(ZnLC)were synthesized through a one-step solvothermal route.The photocatalysts were characterized by X-ray diffraction,Raman spectroscopy,field-emission scanning electron microscopy,energy dispersive X-ray,transmission electron microscopy,UV-vis diffuse reflectance spectroscopy and photo luminescence spectroscopy.The La and Ce doping enhanced the visible light absorption ability of ZnLC and a red shift was detected for ZnLC.Under simulated solar light irradiation,the ZnO doped with 3 at%La and 1 at%Ce(ZnLC1)degrades methylene blue(MB)more effectively than those of pure ZnO,La-doped ZnO(ZnL)and commercially available ZnO.The improved photocatalytic performance of ZnLC1 can be attributed to the high charge separation efficiency as demonstrated by the photoluminescence spectra.Additionally,the photocatalytic experiments reveal that several parameters have their own impact on the MB degradation.Using a variety of radical scavengers,it is discovered that superoxide anion radical plays a crucial role in the degradation of MB.The ZnLC1 is also reused several times without noticeable decrease of photoactivity,indicating that it has a substantial potential for environmental remediation applications.
文摘La modified Ni/T-Al2O3 catalysts prepared by co-precipitation method using NaOH-Na2CO3 as a precipitator show high activity and selectivity for the partial oxidation of methane （POM）. Meanwhile, the addition of La is beneficial for the formation of an active component and stability of support. We investigated some factors including calcining temperature, nickel content, and space velocity, which turned out to have a strong influence on catalytic activity and selectivity. By XRD and TPR, it is concluded that Ni^0 reduced from amorphous NiAl2O4 is the major active component for POM.
文摘A series of perovskite-type complex oxides LaNi1-xRuxO3 were prepared and studied by means of XRD. The effects of some factors on th complex oxides were discussed. Each kind of those perovskite-type complex oxides was used to prepare cathode by composite-electroplating technique. The cathodes were electrochemically charactrized. The results show that these novel cathode exhibit high activities and excellent stabilities during long-term continuous electrolysis with some current interruptions.
基金General Armament Department of the Chinese People's Liberation Army (42001080204)the Natural Science Foundation of Liaoning ,China (2040189)
文摘Nanocrystalline nickel ferrites with substitution of Fe3+ by rare-earth La3+, according to the formula NiLaxFe2-xO4 (with x=0, 0.05, 0.1 and 0.15), were prepared by polyacrylamide gel method. Influences of the amount of La3+ substitution on the structure and electromagnetic properties of NiLaxFe2-xO4 compounds were systematically investigated by DSC-TG, XRD, TEM and wave-guide method. XRD results indicated that the pure spinel-type crystal structure of the NiLaxFe2-xO4 (x=0 and 0.05) was obtained at 500 ℃. TEM results showed that the average particle sizes of NiFe2O4 and NiLa0.1Fe1.9O4 particles were about 10 and 15 nm, respectively. The complex permittivity and complex permeability was measured in the frequency range of 8.2～12.4 GHz. The results revealed that the nanocrystalline NiLaxFe2-xO4 had both dielectric loss and magnetic loss in the frequency range of 8.2～12.4 GHz. The tgδε and tgδm of NiLaxFe2-xO4 (with x=0 and 0.05) decreased with the increase of La3+ ions content, and some strong resonance peaks of the tgδε and tgδm of NiLaxFe2-xO4 (with x=0.1 and 0.15) appeared because of the secondary phases (LaFeO3) and more lattice defects.
基金Financially supported by the National Natural Science Foundation of China(20263003 ) and Science and Technology Bureau of Jiangxi Province
文摘A series of lanthanum containing Ni-base catalysts were prepared by citric acid complex method.Carbon nanotubes (CNT) were synthesized bY catalytic decomposing CH4 over these catalysts and characterized by XRD, TEM and TGA.It is found that the addition of lanthanum can not increase the yield of carbon nanotube, but can make the diameter of carbon nanotube thinner and even.The more the lanthanum addsr, the thinner the diameter of CNTs becomes.With the CNTs prepared on Ni-Mg catalyst, the CNTs prepared on Ni-La-Mg catalyst has better crystallinity and thermal stability.
基金financially supported by Guangdong Basic and Applied Basic Research Foundation (Nos. 2020A1515110473 and 2019A1515110528)。
文摘Designing highly active and stable electrocata-lysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a challenge for energy con-version and storage technology.In this work,a S and N co-doped graphene supported cobalt–nickel sulfide composite catalyst(rGO@SN-CoNi_(2)S_(4))was synthesized simply via a one-step hydrothermal method.The as-synthesized CoNi_(2)S_(4)particles grew in a mosaic manner inside GO lamellae and were encapsulated with graphene.As a bifunctional catalyst,the r GO@SN-CoNi_(2)S_(4)exhibits excellent electrocatalytic performance under alkaline con-ditions,which only required the overpotential of 142.6 mV(vs.RHE)and 310 m V(vs.RHE)to deliver a current density of 10 mA·cm^(-2) for HER and OER,respectively.The good hydrophilicity of the r GO@SN,the pure phase of bimetallic structure,and the chemical coupling/interaction between the CoNi_(2)S_(4)and the rGO@SN are attributable to be the possible reasons responsible for the higher HER and OER catalytic activities.Additionally,the rGO@SN-CoNi_(2)S_(4)also shows a great potential for serving as an excellent cathode and anode electrolyzer during the water splitting process.
