The carbothermic reduction of Panzhihua ilmenite with various additions of activated carbon was investigated byisothermal experiments over the temperature range of1373to1773K in the argon atmosphere.According to the r...The carbothermic reduction of Panzhihua ilmenite with various additions of activated carbon was investigated byisothermal experiments over the temperature range of1373to1773K in the argon atmosphere.According to the reaction kineticsrecorded by the infrared gas analyzer,it was found that the amount of carbon addition had little influence on the reaction rates atvarious temperatures except1473K.When the reaction temperature was above the eutectic temperature of1427K of Fe?C binarysystem,part of carbon would dissolve into Fe to form a liquid phase,which made the liquid Fe as a diffusion channel of carbon todiffuse to the reaction interface.The carbothermic reduction above1573K obeyed the shrinking-core model.The mass fraction ofTiC could be determined by the standard addition technique.展开更多
Vanadium oxide （VOx） nanostructures, synthesized by hydrothermal treatment using dodecylamine as template, were evaluated for the selective catalytic reduction of NOx with ammonia （NH3-SCR）, The effect of solvent ...Vanadium oxide （VOx） nanostructures, synthesized by hydrothermal treatment using dodecylamine as template, were evaluated for the selective catalytic reduction of NOx with ammonia （NH3-SCR）, The effect of solvent type in the reaction mixture （EtOH/（EtOH ＋ H20）） and time of hydrolysis was studied. The obtained materials were characterized by XRD, SEM, TEM and BET, The VOx nanorods （80-120 nm diameter and 1-4 μm length） were synthesized in 25 vol% EtOH/（EtOH ＋ H20） and the open-ended multiwalled VOx nanotube （50-100 nm inner diameter, 110-180 nm outer diameter and 0,5-2 pm length） synthesized in 50 vol% EtOH/（EtOH ＋ H20）. VOx nanotuhes performed the superior NH3-SCR activity under a gas hourly space velocity of 12,000 h-1 at low temperature of 250 ~C （NOx conversion of 893g ＆ N2 selectivity of 100%）, while most of the developed Vanadia base catalysts are active at high temperature （〉350 ℃）. The superior NH3-SCR activity ofVOx nanotubes at low tem- perature is related to nanocrystalline structure, special nanotube morphology as well as high specific surface area.展开更多
In this work,a facile process was reported to fabricate amorphous carbon-coated MnO micropeanuts(MPs)with 1.8μm in length and 1.0μm in width using hydrothermal reaction followed by heat treatment in the oxygen-free ...In this work,a facile process was reported to fabricate amorphous carbon-coated MnO micropeanuts(MPs)with 1.8μm in length and 1.0μm in width using hydrothermal reaction followed by heat treatment in the oxygen-free environment.With Mn Cl_2 and KMnO_4 dissolved in the mixture of ethylene glycol and water,MnCO_3 MP precursors were obtained via the hydrothermal reaction with dopamine as surfactant.Then MnCO_3 MP was annealed at 600°C in the N_2 atmosphere and was transformed into MnO MP,and simultaneously the formed polydopamine during the hydrothermal reaction was carbonized to produce amorphous carbon-coating on the MnO MP surface.In contrast,MnCO_3 nanoparticle(NP)precursor was formed without the addition of dopamine and MnO NP agglomerates were prepared after pyrolysis.The carbonization of polydopamine during thermolysis improves the electrical conductivity and thermal stability of the MnO MP and thus its electrochemical performance as electrode materials for lithium ion battery.Hopefully,this facile strategy for fabricating and designing carbon-coated materials would inspire more novel nanostructures and applications thereof.展开更多
基金Project(FRF-TP-15-009A3) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(U1460201) supported by the National Natural Science Foundation of China
文摘The carbothermic reduction of Panzhihua ilmenite with various additions of activated carbon was investigated byisothermal experiments over the temperature range of1373to1773K in the argon atmosphere.According to the reaction kineticsrecorded by the infrared gas analyzer,it was found that the amount of carbon addition had little influence on the reaction rates atvarious temperatures except1473K.When the reaction temperature was above the eutectic temperature of1427K of Fe?C binarysystem,part of carbon would dissolve into Fe to form a liquid phase,which made the liquid Fe as a diffusion channel of carbon todiffuse to the reaction interface.The carbothermic reduction above1573K obeyed the shrinking-core model.The mass fraction ofTiC could be determined by the standard addition technique.
基金the Iran Nanotechnology Initiative Council for the financial and other supports
文摘Vanadium oxide （VOx） nanostructures, synthesized by hydrothermal treatment using dodecylamine as template, were evaluated for the selective catalytic reduction of NOx with ammonia （NH3-SCR）, The effect of solvent type in the reaction mixture （EtOH/（EtOH ＋ H20）） and time of hydrolysis was studied. The obtained materials were characterized by XRD, SEM, TEM and BET, The VOx nanorods （80-120 nm diameter and 1-4 μm length） were synthesized in 25 vol% EtOH/（EtOH ＋ H20） and the open-ended multiwalled VOx nanotube （50-100 nm inner diameter, 110-180 nm outer diameter and 0,5-2 pm length） synthesized in 50 vol% EtOH/（EtOH ＋ H20）. VOx nanotuhes performed the superior NH3-SCR activity under a gas hourly space velocity of 12,000 h-1 at low temperature of 250 ~C （NOx conversion of 893g ＆ N2 selectivity of 100%）, while most of the developed Vanadia base catalysts are active at high temperature （〉350 ℃）. The superior NH3-SCR activity ofVOx nanotubes at low tem- perature is related to nanocrystalline structure, special nanotube morphology as well as high specific surface area.
基金the National Natural Science Foundation of China(21303249,21301187,21425103,21473240)the Natural Science Foundation of Jiangsu province,China(BK2012007)
文摘In this work,a facile process was reported to fabricate amorphous carbon-coated MnO micropeanuts(MPs)with 1.8μm in length and 1.0μm in width using hydrothermal reaction followed by heat treatment in the oxygen-free environment.With Mn Cl_2 and KMnO_4 dissolved in the mixture of ethylene glycol and water,MnCO_3 MP precursors were obtained via the hydrothermal reaction with dopamine as surfactant.Then MnCO_3 MP was annealed at 600°C in the N_2 atmosphere and was transformed into MnO MP,and simultaneously the formed polydopamine during the hydrothermal reaction was carbonized to produce amorphous carbon-coating on the MnO MP surface.In contrast,MnCO_3 nanoparticle(NP)precursor was formed without the addition of dopamine and MnO NP agglomerates were prepared after pyrolysis.The carbonization of polydopamine during thermolysis improves the electrical conductivity and thermal stability of the MnO MP and thus its electrochemical performance as electrode materials for lithium ion battery.Hopefully,this facile strategy for fabricating and designing carbon-coated materials would inspire more novel nanostructures and applications thereof.
