The γ-ray radiation will speed up the discharge of the storedcharge in nonvolatile MNOS structure. The radiation absorptionmechanism to enhance the discharge is discussed. A direct radiationemission model from the in...The γ-ray radiation will speed up the discharge of the storedcharge in nonvolatile MNOS structure. The radiation absorptionmechanism to enhance the discharge is discussed. A direct radiationemission model from the interface traps distributing both in energylevel and in space is given. The theoretical results based on thismodel are in good agreement with experimental measurements.展开更多
近年来,过渡金属氧化物已被认为是最有希望代替贵金属作为锂氧(Li-O2)电池阴极催化剂的材料。本文研究了一种由静电纺纤维煅烧后自发形成的MnO纳米颗粒作为Li-O2电池的高效催化剂。物性表征的结果显示成功合成了平均粒径为61.82 nm的Mn...近年来,过渡金属氧化物已被认为是最有希望代替贵金属作为锂氧(Li-O2)电池阴极催化剂的材料。本文研究了一种由静电纺纤维煅烧后自发形成的MnO纳米颗粒作为Li-O2电池的高效催化剂。物性表征的结果显示成功合成了平均粒径为61.82 nm的MnO纳米颗粒,为立方晶系结构,作为Li-O2电池阴极在500次循环中表现出优异的循环稳定性,首次充电过电位为0.46 V,在500 mA·g−1的高电流密度下实现了1000 h的稳定循环,优于大多数已报道的用于Li-O2电池的MnOx催化剂。In recent years, transition metal oxides have been considered the most promising materials to replace precious metals as cathode catalysts for lithium-oxygen batteries. This study investigates MnO nanoparticles that spontaneously form after calcining electrospun fibers as an efficient catalyst for lithium-oxygen (Li-O2) batteries. Physical characterization shows that MnO nanoparticles with an average particle size of 61.82 nm and a cubic crystal structure were successfully synthesized. They exhibit excellent cycling stability as a cathode in Li-O2 batteries, enduring over 500 cycles with an initial overpotential of 0.46 V. Concurrent, they also achieve stable cycling for 1000 hours at a high current density of 500 mA·g−1, outperforming most reported catalysts such as MnOx for Li-O2 batteries.展开更多
Al-doped manganese dioxide(MnO_(2))was synthesized by simple hydrothermal method,and a controllable phase transition of the MnO_(2)crystal phase fromβtoδwas achieved.The effects of Al doping concentration on the str...Al-doped manganese dioxide(MnO_(2))was synthesized by simple hydrothermal method,and a controllable phase transition of the MnO_(2)crystal phase fromβtoδwas achieved.The effects of Al doping concentration on the structure and electrochemical properties of electrode materials were studied in detail.The results show that the controlled synthesis requires a synergy between KMnO_(4),MnCl_(2)and AlCl_(3),and that Al^(3+)plays an important role.Compared with the pure phase MnO_(2),the crystallinity of Al-doped MnO_(2)decreases and the specific surface area increases,which provides more active sites for the electrode material.When 3 mmol Al^(3+)is added,the prepared MnO_(2)-3 has the largest specific capacitance and the highest rate performance.The energy density of the asymmetric supercapacitor(ASC)with MnO_(2)-3 as the positive electrode and activated carbon(AC)as the negative electrode can reach 18.4 W·h/kg at the power density of 400 W/kg,and the capacity can maintain 90%of the initial value after 20000 cycles,indicating that Al-doped MnO_(2)has certain practical application value.This study provides favorable guidance for MnO_(2)as a high performance electrode material.展开更多
The immobilization of catalysts on supporting substrates for the removal of organic pollutants is a crucial strategy for mitigating catalyst loss during wastewater treatment.This study presented a rapid and cost-effec...The immobilization of catalysts on supporting substrates for the removal of organic pollutants is a crucial strategy for mitigating catalyst loss during wastewater treatment.This study presented a rapid and cost-effective direct heating method for synthesizing MnO2 nanoflowers on coil substrates for the removal of organic pollutants.Traditional methods often require high power,expensive equipment,and long synthesis times.In contrast,the direct heating approach successfully synthesized MnO2 nanoflowers in just 10 min with a heating power of approximately 40 W·h after the heating power and duration were optimized.These nanoflowers effectively degraded 99%Rhodamine B in 60 min with consistent repeatability.The catalytic mechanisms are attributed to crystal defects in MnO2,which generate electrons to produce H2O2.Mn2+ions in the acidic solution further dissociate H2O2 molecules into hydroxyl radicals(·OH).The high efficiency of this synthesis method and the excellent reusability of MnO2 nanoflowers highlight their potential as a promising solution for the development of supporting MnO2 catalysts for organic dye removal applications.展开更多
文摘The γ-ray radiation will speed up the discharge of the storedcharge in nonvolatile MNOS structure. The radiation absorptionmechanism to enhance the discharge is discussed. A direct radiationemission model from the interface traps distributing both in energylevel and in space is given. The theoretical results based on thismodel are in good agreement with experimental measurements.
文摘近年来,过渡金属氧化物已被认为是最有希望代替贵金属作为锂氧(Li-O2)电池阴极催化剂的材料。本文研究了一种由静电纺纤维煅烧后自发形成的MnO纳米颗粒作为Li-O2电池的高效催化剂。物性表征的结果显示成功合成了平均粒径为61.82 nm的MnO纳米颗粒,为立方晶系结构,作为Li-O2电池阴极在500次循环中表现出优异的循环稳定性,首次充电过电位为0.46 V,在500 mA·g−1的高电流密度下实现了1000 h的稳定循环,优于大多数已报道的用于Li-O2电池的MnOx催化剂。In recent years, transition metal oxides have been considered the most promising materials to replace precious metals as cathode catalysts for lithium-oxygen batteries. This study investigates MnO nanoparticles that spontaneously form after calcining electrospun fibers as an efficient catalyst for lithium-oxygen (Li-O2) batteries. Physical characterization shows that MnO nanoparticles with an average particle size of 61.82 nm and a cubic crystal structure were successfully synthesized. They exhibit excellent cycling stability as a cathode in Li-O2 batteries, enduring over 500 cycles with an initial overpotential of 0.46 V. Concurrent, they also achieve stable cycling for 1000 hours at a high current density of 500 mA·g−1, outperforming most reported catalysts such as MnOx for Li-O2 batteries.
基金Project(202203021221138)supported by the Collaborative Innovation Center for Shanxi Advanced Permanent Materials and Technologythe 1331 Engineering of Shanxi ProvinceFundamental Research Program of Shanxi Province,China。
文摘Al-doped manganese dioxide(MnO_(2))was synthesized by simple hydrothermal method,and a controllable phase transition of the MnO_(2)crystal phase fromβtoδwas achieved.The effects of Al doping concentration on the structure and electrochemical properties of electrode materials were studied in detail.The results show that the controlled synthesis requires a synergy between KMnO_(4),MnCl_(2)and AlCl_(3),and that Al^(3+)plays an important role.Compared with the pure phase MnO_(2),the crystallinity of Al-doped MnO_(2)decreases and the specific surface area increases,which provides more active sites for the electrode material.When 3 mmol Al^(3+)is added,the prepared MnO_(2)-3 has the largest specific capacitance and the highest rate performance.The energy density of the asymmetric supercapacitor(ASC)with MnO_(2)-3 as the positive electrode and activated carbon(AC)as the negative electrode can reach 18.4 W·h/kg at the power density of 400 W/kg,and the capacity can maintain 90%of the initial value after 20000 cycles,indicating that Al-doped MnO_(2)has certain practical application value.This study provides favorable guidance for MnO_(2)as a high performance electrode material.
基金supported by Ministry of Higher Education,Malaysia,through the Fundamental Research Grant Scheme(FRGS)(Grant No.FRGS/1/2020/TK0/USM/02/27)。
文摘The immobilization of catalysts on supporting substrates for the removal of organic pollutants is a crucial strategy for mitigating catalyst loss during wastewater treatment.This study presented a rapid and cost-effective direct heating method for synthesizing MnO2 nanoflowers on coil substrates for the removal of organic pollutants.Traditional methods often require high power,expensive equipment,and long synthesis times.In contrast,the direct heating approach successfully synthesized MnO2 nanoflowers in just 10 min with a heating power of approximately 40 W·h after the heating power and duration were optimized.These nanoflowers effectively degraded 99%Rhodamine B in 60 min with consistent repeatability.The catalytic mechanisms are attributed to crystal defects in MnO2,which generate electrons to produce H2O2.Mn2+ions in the acidic solution further dissociate H2O2 molecules into hydroxyl radicals(·OH).The high efficiency of this synthesis method and the excellent reusability of MnO2 nanoflowers highlight their potential as a promising solution for the development of supporting MnO2 catalysts for organic dye removal applications.
