The present work combines polypyrrole with cobalt molybdenum oxide using an in situ surface growth method to adjust impedance matching and explore the microwave absorption performance of the composite material.The com...The present work combines polypyrrole with cobalt molybdenum oxide using an in situ surface growth method to adjust impedance matching and explore the microwave absorption performance of the composite material.The complex dielectric constant and magnetic permeability of the samples are measured in the frequency range of 2 to 18 GHz using a vector network analyzer,and their reflection loss(RL)value is investigated.The results show that the obtained PPy/Co_(x)Mo_(y)O_(z)composite exhibits excellent absorption performance at 17.68 GHz under a matching thickness of 2.0 mm,with an RL_(min)of-46.02 dB and an effective absorption bandwidth of 4.08 GHz.The excellent absorption performance can be attributed to the combined effect of multion loss mechanisms,including conduction loss,interface polarization,dipole polarization and eddy current loss.展开更多
The study reports progress in developing a molybdenum carbide-based catalyst for co-processing ethane and CO_(2).The cobalt promoting of molybdenum carbide improved the activity and stability of ethane transformation ...The study reports progress in developing a molybdenum carbide-based catalyst for co-processing ethane and CO_(2).The cobalt promoting of molybdenum carbide improved the activity and stability of ethane transformation in the presence of CO_(2) substantially without any impact on ethylene selectivity.The Mo-Co supported catalyst also showed interesting performance in catalyzing ethane dry reforming and that application could be a perspective further use for this system.In addition,the comprehensive analysis of mono-and bi-metallic catalysts revealed that Co-promoting prevented rapid Mo-carbide oxidation.Further,tuning operation conditions allowed to control catalyst’s selectivity and maximize CO_(2) utilization or ethylene formation.展开更多
Silicon(Si)holds promise as an anode material for lithium-ion batteries(LIBs)as it is widely avail-able and characterized by high specific capacity and suitable working potential.However,the relatively low electrical ...Silicon(Si)holds promise as an anode material for lithium-ion batteries(LIBs)as it is widely avail-able and characterized by high specific capacity and suitable working potential.However,the relatively low electrical conductivity of Si and the significantly high extent of volume expansion realized dur-ing lithiation hinder its practical application.We prepared N-doped carbon polyhedral micro cage en-capsulated Si nanoparticles derived from Co-Mo bimetal metal-organic framework(MOFs)(denoted as Si/CoMo@NCP)and explored their lithium storage performance as anode materials to address these prob-lems.The Si/CoMo@NCP anode exhibited a high reversible lithium storage capacity(1013 mAh g^(−1)at 0.5 A g^(−1)after 100 cycles),stable cycle performance(745 mAh g^(−1)at 1 A g^(−1)after 400 cycles),and excellent rate performance(723 mAh g^(−1)at 2 A g^(−1)).Also,the constructed the full-cell NCM 811//Si/CoMo@NCP exhibited well reversible capacity.The excellent electrochemical performances of Si/CoMo@NCP were at-tributed to two unique properties.The encapsulation of NCP with doped nitrogen and porous structural carbon improves the electrical conductivity and cycling stability of the molecules.The introductions of metallic cobalt and its oxides help to improve the rate capability and lithiation capacity of the materials following multi-electron reaction mechanisms.展开更多
基金supported by the National Natural Science Foundation of China(22165032)
文摘The present work combines polypyrrole with cobalt molybdenum oxide using an in situ surface growth method to adjust impedance matching and explore the microwave absorption performance of the composite material.The complex dielectric constant and magnetic permeability of the samples are measured in the frequency range of 2 to 18 GHz using a vector network analyzer,and their reflection loss(RL)value is investigated.The results show that the obtained PPy/Co_(x)Mo_(y)O_(z)composite exhibits excellent absorption performance at 17.68 GHz under a matching thickness of 2.0 mm,with an RL_(min)of-46.02 dB and an effective absorption bandwidth of 4.08 GHz.The excellent absorption performance can be attributed to the combined effect of multion loss mechanisms,including conduction loss,interface polarization,dipole polarization and eddy current loss.
文摘The study reports progress in developing a molybdenum carbide-based catalyst for co-processing ethane and CO_(2).The cobalt promoting of molybdenum carbide improved the activity and stability of ethane transformation in the presence of CO_(2) substantially without any impact on ethylene selectivity.The Mo-Co supported catalyst also showed interesting performance in catalyzing ethane dry reforming and that application could be a perspective further use for this system.In addition,the comprehensive analysis of mono-and bi-metallic catalysts revealed that Co-promoting prevented rapid Mo-carbide oxidation.Further,tuning operation conditions allowed to control catalyst’s selectivity and maximize CO_(2) utilization or ethylene formation.
基金the National Natural Science Foundation of China(NSFC,No.21203116)the Innovation Capability Support Plan of Shaanxi Province(Grant No.2022WGZJ-25)the Foundation of Shaanxi University of Science and Tech-nology(Grant No.210210031 and 210210032).
文摘Silicon(Si)holds promise as an anode material for lithium-ion batteries(LIBs)as it is widely avail-able and characterized by high specific capacity and suitable working potential.However,the relatively low electrical conductivity of Si and the significantly high extent of volume expansion realized dur-ing lithiation hinder its practical application.We prepared N-doped carbon polyhedral micro cage en-capsulated Si nanoparticles derived from Co-Mo bimetal metal-organic framework(MOFs)(denoted as Si/CoMo@NCP)and explored their lithium storage performance as anode materials to address these prob-lems.The Si/CoMo@NCP anode exhibited a high reversible lithium storage capacity(1013 mAh g^(−1)at 0.5 A g^(−1)after 100 cycles),stable cycle performance(745 mAh g^(−1)at 1 A g^(−1)after 400 cycles),and excellent rate performance(723 mAh g^(−1)at 2 A g^(−1)).Also,the constructed the full-cell NCM 811//Si/CoMo@NCP exhibited well reversible capacity.The excellent electrochemical performances of Si/CoMo@NCP were at-tributed to two unique properties.The encapsulation of NCP with doped nitrogen and porous structural carbon improves the electrical conductivity and cycling stability of the molecules.The introductions of metallic cobalt and its oxides help to improve the rate capability and lithiation capacity of the materials following multi-electron reaction mechanisms.
