The microscopic morphology of electromagnetic wave absorbers influences the multiple reflections of electromagnetic waves and impedance matching,determining the absorption properties.Herein,the urchin-shaped bimetalli...The microscopic morphology of electromagnetic wave absorbers influences the multiple reflections of electromagnetic waves and impedance matching,determining the absorption properties.Herein,the urchin-shaped bimetallic nickel-cobalt oxide/carbon(NiCo_(2)O_(4)/C)composites are prepared via a hy-drothermal route,whose absorption properties are investigated by different morphologies regulated by changing calcination temperature.A minimum reflection loss(RL_(min))of-75.26 dB is achieved at a match-ing thickness of 1.5 mm,and the effective absorption bandwidth(EAB)of 8.96 GHz is achieved at 2 mm.Multi-advantages of the synthesized NiCo_(2)O_(4)/C composites contribute to satisfactory absorption proper-ties.First,the interweaving of the needle-like structures increases the opportunities for scattering and multiple reflections of incident electromagnetic waves,and builds up a conductive network to facilitate the enhancement of conductive losses.Second,the carbon component in the NiCo_(2)O_(4)/C composites en-hances the interfacial polarization and reduces the density of the absorber.Besides,generous oxygen va-cancy defects are introduced into the NiCo_(2)O_(4)/C composites,which induces defect polarization and dipole polarization.In summary,the ternary coordination of components,defects and morphology led to out-standing electromagnetic wave absorption,which lightened the path for improving the electromagnetic wave absorption property and enriching the family of NiCo_(2)O_(4) absorbers with excellent performance.展开更多
A subsidiary role of electrochemical neutralization energy(ENE)stored in waste acid/base presents a sustainable and economically viable solution for the production of value-added chemicals and saving energy.Here we de...A subsidiary role of electrochemical neutralization energy(ENE)stored in waste acid/base presents a sustainable and economically viable solution for the production of value-added chemicals and saving energy.Here we demonstrate a pH-asymmetric electrolyzer with a bipolar membrane to realize sustainable and efficient electrocatalytic methane oxidation coupling with hydrogen production at a low energy cost.This approach affords a C1/molecule production rate of up to 2.6 mmol g_(NiO) ^(-1) h^(-1)with simultaneous H_(2) production at a potential as low as 1.4 V.Furthermore,the electrocatalyst achieves sustained catalysis at 1 mA for over 24 h with lower operation voltage by 700 mV under auxiliary ENE supply,which means the cell electricity manner would enable an energy elimination of 36.9%energy saving comparing with state-of-the-art electrolyzers.In situ Raman spectroscopy and density functional theory calculation reveal the catalytic mechanism of the important role of Ni^(III)–O∙–Ni^(III)–O–for the electrochemical methane oxidation(EOM).Meanwhile,the pH-asymmetric integrated cell with simulated and complex waste acid-base solutions showcases a lower voltage of 1.62 V at 1 mA applied current with the same catalysts.Additionally,the device demonstrates negligible degradation at 10 mA cm^(−2),suggesting high overall durability for EOM.Techno-economic evaluation is also conducted to present the energy-saving and profit advantages with less oxygen evolution reaction(OER)competition.This work opens a pathway for prospective applications for the production of commodity chemicals simultaneously in one electrolyzer,which can even turn waste acid and base into resources.展开更多
基金financially supported by the National Natu-ral Science Foundation of China(No.52207249)the Natural Sci-ence Foundation of Shandong Province(No.ZR2022ME089)+2 种基金the research program of Top Talent Project of Yantai University(No.1115/2220001)the Yantai Basic Research Project(No.2022JCYJ04)the Science Fund of Shandong Laboratory of Advanced Ma-terials and Green Manufacturing(No.AMGM2021F11).The au-thors would like to thank the Deanship of Scientific Research at Umm Al-Qura University for supporting this work by Grant Code:22UQU4320141DSR72.
文摘The microscopic morphology of electromagnetic wave absorbers influences the multiple reflections of electromagnetic waves and impedance matching,determining the absorption properties.Herein,the urchin-shaped bimetallic nickel-cobalt oxide/carbon(NiCo_(2)O_(4)/C)composites are prepared via a hy-drothermal route,whose absorption properties are investigated by different morphologies regulated by changing calcination temperature.A minimum reflection loss(RL_(min))of-75.26 dB is achieved at a match-ing thickness of 1.5 mm,and the effective absorption bandwidth(EAB)of 8.96 GHz is achieved at 2 mm.Multi-advantages of the synthesized NiCo_(2)O_(4)/C composites contribute to satisfactory absorption proper-ties.First,the interweaving of the needle-like structures increases the opportunities for scattering and multiple reflections of incident electromagnetic waves,and builds up a conductive network to facilitate the enhancement of conductive losses.Second,the carbon component in the NiCo_(2)O_(4)/C composites en-hances the interfacial polarization and reduces the density of the absorber.Besides,generous oxygen va-cancy defects are introduced into the NiCo_(2)O_(4)/C composites,which induces defect polarization and dipole polarization.In summary,the ternary coordination of components,defects and morphology led to out-standing electromagnetic wave absorption,which lightened the path for improving the electromagnetic wave absorption property and enriching the family of NiCo_(2)O_(4) absorbers with excellent performance.
基金supported by the Shanghai Key Laboratory of Hydrogen Science&Center of Hydrogen Science of Shanghai Jiao Tong University and the Shanghai High-Level Oversea Talents Award.
文摘A subsidiary role of electrochemical neutralization energy(ENE)stored in waste acid/base presents a sustainable and economically viable solution for the production of value-added chemicals and saving energy.Here we demonstrate a pH-asymmetric electrolyzer with a bipolar membrane to realize sustainable and efficient electrocatalytic methane oxidation coupling with hydrogen production at a low energy cost.This approach affords a C1/molecule production rate of up to 2.6 mmol g_(NiO) ^(-1) h^(-1)with simultaneous H_(2) production at a potential as low as 1.4 V.Furthermore,the electrocatalyst achieves sustained catalysis at 1 mA for over 24 h with lower operation voltage by 700 mV under auxiliary ENE supply,which means the cell electricity manner would enable an energy elimination of 36.9%energy saving comparing with state-of-the-art electrolyzers.In situ Raman spectroscopy and density functional theory calculation reveal the catalytic mechanism of the important role of Ni^(III)–O∙–Ni^(III)–O–for the electrochemical methane oxidation(EOM).Meanwhile,the pH-asymmetric integrated cell with simulated and complex waste acid-base solutions showcases a lower voltage of 1.62 V at 1 mA applied current with the same catalysts.Additionally,the device demonstrates negligible degradation at 10 mA cm^(−2),suggesting high overall durability for EOM.Techno-economic evaluation is also conducted to present the energy-saving and profit advantages with less oxygen evolution reaction(OER)competition.This work opens a pathway for prospective applications for the production of commodity chemicals simultaneously in one electrolyzer,which can even turn waste acid and base into resources.
