Lanthanum hydroxide nanorods with a diameter of 10-20 nm and length up to 100-200 nm were synthesized through a direct reaction of La(NO3)3 and KOH under hydrothermal microemulsion conditions.X-ray diffraction（XRD） ...Lanthanum hydroxide nanorods with a diameter of 10-20 nm and length up to 100-200 nm were synthesized through a direct reaction of La(NO3)3 and KOH under hydrothermal microemulsion conditions.X-ray diffraction（XRD） and scanning electron microscope（SEM） were employed for the characterization of the structure,compositions and morphology of the obtained products.The results showed that the molar ratio of water to the surfactant CTAB,concentration of La(NO3)3,reactant temperature and reactant time all could affect the morphology and size of the lanthanum hydroxide nanorods.展开更多
Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after th...Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La（OH）3 nanorods.The BiOI@La（OH）3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La（OH）3 nanorods.The results show that the energy levels between the La（OH）3 and BiOI phases matched well with each other,thus forming a heterojunctioned BiOI@La（OH）3 structure.This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface,resulting in enhanced photocatalytic performance under visible light irradiation.The photocatalytic performance of BiOI@La（OH）3 is shown to be dependent on the mass ratio of BiOI to La（OH）3.The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La（OH）3 is controlled at 1.5.A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers.A new photocatalytic mechanism for BiOI@La（OH）3 heterostructures is proposed,which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction.Importantly,the as-prepared BiOI@La（OH）3 heterostructures exhibited a high photochemical stability after multiple reaction runs.Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor,which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.展开更多
La（OH）3 nanorods with diameters of 20-40 nm and lengths of 200-300 nm were synthesized by a hydrothermal microemulsion method. The structure and morphology of the final products were characterized by X-ray powder di...La（OH）3 nanorods with diameters of 20-40 nm and lengths of 200-300 nm were synthesized by a hydrothermal microemulsion method. The structure and morphology of the final products were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, and field emission scanning electron microscope （FESEM）.展开更多
Lanthanum hydroxide/graphene oxide nanocomposites(La(OH)3/GO)modified by octadecylamine(OCA),oleylamine(OLA),and polyvinylpyrrolidone(PVP)were prepared,respectively,as the base oil additives.The dispersion stability o...Lanthanum hydroxide/graphene oxide nanocomposites(La(OH)3/GO)modified by octadecylamine(OCA),oleylamine(OLA),and polyvinylpyrrolidone(PVP)were prepared,respectively,as the base oil additives.The dispersion stability of different modified La(OH)3/GO in base oil was studied by means of centrifugation.The tribological properties of oleophilic La(OH)3/GO in base oil were investigated using an UMT ball-disc tribometer.The micro-morphology and chemical composition of the worn surface were characterized by 3 D laser microscope,SEM,EDS,XPS,and Raman spectroscopy,respectively.The wettability performance of the worn surface was also studied based on the contact angle measurements.The test results showed that the OLA-La(OH)3/GO nanocomposites had good dispersion stability in base oil.The anti-wear performance of base oil was improved significantly by the addition of OLA-La(OH)3/GO nanocomposites.The characterizations of worn surface showed that the OLA-La(OH)3/GO nanocomposites could form the metal oxide and graphene protective films effectively on the friction interface and thus increased the oil wettability of the worn surface,thereby resulting in an improved wear resistance.展开更多
The lanthanum carbide alloy was induction melted in vacuum induction melting furnace from lanthanum and graphite with the mass ratio of 89：11. Lanthanum hydroxide （La（OH）3） nanopowders were prepared by a simple h...The lanthanum carbide alloy was induction melted in vacuum induction melting furnace from lanthanum and graphite with the mass ratio of 89：11. Lanthanum hydroxide （La（OH）3） nanopowders were prepared by a simple hydrolysis of lanthanum carbide at room temperature under normal atmospheric pressure without any surfactant. X-ray diffraction （XRD） showed that the nanoparticles were with a hex-agonal structure. The effect factors such as reaction time,reaction temperature and the mass ratio of lanthanum carbide powders to H2O on BET surface area of the obtained nanopowders were investigated. Furthermore,transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM） showed that nanopowders behaved the morphology of short nanorod. The longitudinal growth direction of the nanorod had an angle of about 14° with the （101） lattice plane and the lateral growth direction had an angle of about 35° with the （200） lattice plane. The mechanism of formation of nanorod was discussed on the basis of the experimental results.展开更多
文摘Lanthanum hydroxide nanorods with a diameter of 10-20 nm and length up to 100-200 nm were synthesized through a direct reaction of La(NO3)3 and KOH under hydrothermal microemulsion conditions.X-ray diffraction（XRD） and scanning electron microscope（SEM） were employed for the characterization of the structure,compositions and morphology of the obtained products.The results showed that the molar ratio of water to the surfactant CTAB,concentration of La(NO3)3,reactant temperature and reactant time all could affect the morphology and size of the lanthanum hydroxide nanorods.
基金supported by the National Key Research and Development Project (2016YFC0204702)the National Natural Science Foundation of China (51478070, 21501016, 51108487)+2 种基金the Innovative Research Team of Chongqing (CXTDG201602014)the Natural Science Foundation of Chongqing (cstc2016jcyjA0481)Youth Innovation Promotion Association of Chinese Academy of Sciences (2015316)~~
文摘Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La（OH）3 nanorods.The BiOI@La（OH）3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La（OH）3 nanorods.The results show that the energy levels between the La（OH）3 and BiOI phases matched well with each other,thus forming a heterojunctioned BiOI@La（OH）3 structure.This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface,resulting in enhanced photocatalytic performance under visible light irradiation.The photocatalytic performance of BiOI@La（OH）3 is shown to be dependent on the mass ratio of BiOI to La（OH）3.The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La（OH）3 is controlled at 1.5.A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers.A new photocatalytic mechanism for BiOI@La（OH）3 heterostructures is proposed,which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction.Importantly,the as-prepared BiOI@La（OH）3 heterostructures exhibited a high photochemical stability after multiple reaction runs.Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor,which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.
基金supported by the National Natural Science Foundation of China (20923001,21025312)the National Basic Research Program of China (973 Program,2013CB933100)~~
文摘La（OH）3 nanorods with diameters of 20-40 nm and lengths of 200-300 nm were synthesized by a hydrothermal microemulsion method. The structure and morphology of the final products were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, and field emission scanning electron microscope （FESEM）.
基金supported by the National Natural Science Foundation of China(Grant No.51675153)。
文摘Lanthanum hydroxide/graphene oxide nanocomposites(La(OH)3/GO)modified by octadecylamine(OCA),oleylamine(OLA),and polyvinylpyrrolidone(PVP)were prepared,respectively,as the base oil additives.The dispersion stability of different modified La(OH)3/GO in base oil was studied by means of centrifugation.The tribological properties of oleophilic La(OH)3/GO in base oil were investigated using an UMT ball-disc tribometer.The micro-morphology and chemical composition of the worn surface were characterized by 3 D laser microscope,SEM,EDS,XPS,and Raman spectroscopy,respectively.The wettability performance of the worn surface was also studied based on the contact angle measurements.The test results showed that the OLA-La(OH)3/GO nanocomposites had good dispersion stability in base oil.The anti-wear performance of base oil was improved significantly by the addition of OLA-La(OH)3/GO nanocomposites.The characterizations of worn surface showed that the OLA-La(OH)3/GO nanocomposites could form the metal oxide and graphene protective films effectively on the friction interface and thus increased the oil wettability of the worn surface,thereby resulting in an improved wear resistance.
基金Project supported by Shanghai Leading Academic Discipline Project (S30107)
文摘The lanthanum carbide alloy was induction melted in vacuum induction melting furnace from lanthanum and graphite with the mass ratio of 89：11. Lanthanum hydroxide （La（OH）3） nanopowders were prepared by a simple hydrolysis of lanthanum carbide at room temperature under normal atmospheric pressure without any surfactant. X-ray diffraction （XRD） showed that the nanoparticles were with a hex-agonal structure. The effect factors such as reaction time,reaction temperature and the mass ratio of lanthanum carbide powders to H2O on BET surface area of the obtained nanopowders were investigated. Furthermore,transmission electron microscopy （TEM） and high-resolution transmission electron microscopy （HRTEM） showed that nanopowders behaved the morphology of short nanorod. The longitudinal growth direction of the nanorod had an angle of about 14° with the （101） lattice plane and the lateral growth direction had an angle of about 35° with the （200） lattice plane. The mechanism of formation of nanorod was discussed on the basis of the experimental results.
