Economical,efficient and stable transition-metal electrocatalysts are considered great candidatures for replacing noble-metal materials for alkaline hydrogen production.Hence,corrosion engineering and mild phosphating...Economical,efficient and stable transition-metal electrocatalysts are considered great candidatures for replacing noble-metal materials for alkaline hydrogen production.Hence,corrosion engineering and mild phosphating processes were adopted to construct NiFe phosphide encapsulated in nitrogen-doped carbon(NiFe-P@NC).The latter presented a hierarchical morphology with an interconnected threedimensional porous structure.The unique NiFe-P@NC presented excellent hydrogen evolution reaction(HER)performance with an overpotential of 40 mV at 10 mA cm^(−2) along with excellent stability in KOH solution(1 M).Notably,NiFe-P@NC required low overpotentials of 149 mV and 280 mV to afford 100 mA cm^(−2) for HER and oxygen evolution reaction(OER)performance in KOH(1 M)+seawater electrolyte,respectively.Furthermore,as a remarkable bifunctional electrocatalyst,the assembled NiFe-P@NC||NiFe-P@NC electrolyzer with low cell voltages of 1.77 V and 1.93 V could drive 100 mA cm^(−2) and 500 mA cm^(−2) in alkaline seawater electrolyte.Remarkably,a water-splitting device could be actuated efficiently by sustainable energies to facilitate a source of hydrogen energy.展开更多
Inexpensive and accessible NiFe-based oxygen evolution reaction(OER)electrocatalysts show limitations for practical industrial applications owing to their activity and stability under industrial conditions.Herein,an F...Inexpensive and accessible NiFe-based oxygen evolution reaction(OER)electrocatalysts show limitations for practical industrial applications owing to their activity and stability under industrial conditions.Herein,an FeNi_(2)S_(4)@NiFe–LDH heterostructure is constructed by the molten salt method and interfacial corrosion strategy,in which amorphous NiFe–LDH nanosheets grow in situ on the surface of crystalline FeNi_(2)S_(4) with a nanograss structure.The introduction of amorphous NiFe–LDH can not only optimize the adsorption energy of OER intermediates,but also significantly improve the overall stability and activity of the catalyst by reducing the loss of the S element in FeNi_(2)S_(4).At the same time,the OH^(−)produced by S ion hydrolysis can also promote the in situ construction of NiFe–LDH.Such an amorphous–crystalline structure gives full contribution to the advantages of each component,modulates the nanostructure,and promotes the electron transfer across the interfaces.Consequently,FeNi_(2)S_(4)@NiFe–LDH achieves large current density values of 500 and 1000 mA cm^(−2) for the OER at overpotentials of only 283 and 306 mV in 1 M KOH(25℃)without losing performance for at least 600 h at 500 mA cm^(−2).Under the simulated practical industrial test conditions(6 M KOH,70℃),the same current densities of 500 and 1000 mA cm^(−2) are delivered at the ultra-low overpotentials of 137 and 155 mV with long-term stability at high and low current densities.Such excellent catalyst performance shows its great industrial application prospects.This work also provides a strategy using Earth-abundant materials for realizing large-scale water splitting.展开更多
Layered honeycomb intermetallic phases have attracted considerable research interest due to the wide array of exciting physical properties inherent in these materials.Here,we follow the evolution in structure and elec...Layered honeycomb intermetallic phases have attracted considerable research interest due to the wide array of exciting physical properties inherent in these materials.Here,we follow the evolution in structure and electronic properties of a relatively unexplored material system,Sr_(1−x)Ca_(x)PdAs,as the hexagonal PdAs honeycomb layer in SrPdAs distorts into the orthorhombic CaPdAs structure.The Sr-rich compounds(x=0 to 1/3)form symmetric,hexagonal honeycomb PdAs layers,whereas in the Ca-rich region(x=1/2 to 1)the PdAs layers distort into an orthorhombic structure featuring long and short Pd–Pd distances.This dis tortion occurs when the average Pd–Pd distance falls below 4.21Å.All compounds are observed to exhibit metallic temperature-dependent resistivity trends.There are no apparent discontinuities indicative of metal-to-insulator transitions and the room temperature resistivity values range from 18 to 180 mΩcm.In total,this work maps out the structural and electronic phase diagram of Sr_(1−x)Cax PdAs compounds.展开更多
The adsorption remediation of radioactive contamination from wastewater is scientifically and economically important.In this work,titanium dioxide-modified manganese dioxide(MnO_(2)@TiO_(2))was prepared by immobilizin...The adsorption remediation of radioactive contamination from wastewater is scientifically and economically important.In this work,titanium dioxide-modified manganese dioxide(MnO_(2)@TiO_(2))was prepared by immobilizing crystalline anatase titanium dioxide(TiO_(2))on the surface of alpha manganese dioxide nanowire(MnO_(2)).The base material MnO_(2) nanowire acted as a physical template for the vip TiO_(2),and the formed MnO_(2)@TiO_(2) composite exhibited a highly uniform core–shell nanorod structure.The MnO_(2)@TiO_(2) composite was investigated as an efficient adsorbent for the removal of U(Ⅵ)from aqueous solution.In the same system,MnO_(2)@TiO_(2) exhibited a much higher maximum adsorption capacity(105.3 mg g^(−1))for U(Ⅵ)as compared with MnO_(2)(13.3 mg g^(−1)),showing that the performance of the surface-modified MnO_(2) was greatly improved.The fitting results for kinetic and isothermal models manifested that U(Ⅵ)ion adsorption by MnO_(2)@TiO_(2) involved monolayer chemisorption.Characterization before and after adsorption was performed and the results compared and analyzed carefully,with the conclusion that there might be three kinds of interactions between U(Ⅵ)and MnO_(2)@TiO_(2) during the adsorption process,namely inner-sphere surface complexation,chemical precipitation,and electrostatic interaction.The low-cost,facile fabrication method and efficient performance endow the adsorbent MnO_(2)@TiO_(2) with a high potential for U(Ⅵ)removal from actual wastewater.展开更多
The electronic structure of a compound plays a key role in its functionality and hence its applications.The core-level X-ray spectroscopy technique at the metal L-edge is widely used for probing the valence electronic...The electronic structure of a compound plays a key role in its functionality and hence its applications.The core-level X-ray spectroscopy technique at the metal L-edge is widely used for probing the valence electronic structure.The X-ray spectral features in the metal L-edge energy regime are usually complicated by a multitude of interactions,which make them challenging to interpret.The X-ray absorption spectra(XAS)and the resonant inelastic X-ray scattering(RIXS)spectra in the cobalt L-edge energy regime of tris(2,2’-bipyridine)cobalt compounds[Co^(Ⅱ)(bpy)3]^(2+)and[CoⅢ(bpy)3]3+are calculated using an ab initio restricted active space(RAS)approach.The experimental spectra are nicely reproduced and their spectral features are interpreted in terms of the orbital contributions and the final-state contributions.Unbiased assignments on the spin state of the ground state of these two cobalt compounds have been critically assessed through valence-excited state calculations and the fingerprints of the X-ray spectral features together with the calculations of the branching ratio.展开更多
This study presents the design and fabrication of a ruthenium dioxide(RuO_(2))nanosheets-functionalized tin dioxide(SnO_(2))thin-film gas sensor integrated with a microheater in a suspended membrane structure.The RuO_...This study presents the design and fabrication of a ruthenium dioxide(RuO_(2))nanosheets-functionalized tin dioxide(SnO_(2))thin-film gas sensor integrated with a microheater in a suspended membrane structure.The RuO_(2)nanosheets are synthesized via an intercalation-driven exfoliation process and subsequently deposited onto a sputtered SnO_(2)thin film.Due to the catalytic properties and high surface-to-volume ratio of RuO_(2)nanosheets,the functionalized sensor demonstrates a 337%increase in response(R_(air)/R_(gas))to 10 ppm ethanol compared to pristine SnO_(2)thin film.The sensor achieves sensitive detection from a few parts-per-million(ppm)down to several parts-per-billion(ppb)concentrations of ethanol.Evaluations under varied humidity conditions,as well as selectivity and 28-day stability tests,demonstrate that the RuO_(2)nanosheets-functionalized sensor maintains reliable performance.These results highlight its potential as a sensitive,selective,and low-power solution for ethanol gas detection.Furthermore,the sensor successfully tracks breath alcohol concentration in real-time through controlled alcohol intake experiments,demonstrating its feasibility for practical breath alcohol detection.展开更多
基金funding support provided by the National Natural Science Foundation of China(22002068,52272222 and 52072197)Taishan Scholar Young Talent Program(tsqn201909114)+7 种基金Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(2019KJC004)Outstanding Youth Foundation of Shandong Province,China(ZR2019JQ14)Major Basic Research Program of Natural Science Foundation of Shandong Province(ZR2020ZD09)Major Scientific and Technological Innovation Project(2019JZZY020405)China Postdoctoral Science Foundation(2021M691700)Natural Science Foundation of Shandong Province of China(ZR2019BB002ZR2018BB031)Postdoctoral Innovation Project of Shandong Province,the 111 Project of China(Grant No.D20017).
文摘Economical,efficient and stable transition-metal electrocatalysts are considered great candidatures for replacing noble-metal materials for alkaline hydrogen production.Hence,corrosion engineering and mild phosphating processes were adopted to construct NiFe phosphide encapsulated in nitrogen-doped carbon(NiFe-P@NC).The latter presented a hierarchical morphology with an interconnected threedimensional porous structure.The unique NiFe-P@NC presented excellent hydrogen evolution reaction(HER)performance with an overpotential of 40 mV at 10 mA cm^(−2) along with excellent stability in KOH solution(1 M).Notably,NiFe-P@NC required low overpotentials of 149 mV and 280 mV to afford 100 mA cm^(−2) for HER and oxygen evolution reaction(OER)performance in KOH(1 M)+seawater electrolyte,respectively.Furthermore,as a remarkable bifunctional electrocatalyst,the assembled NiFe-P@NC||NiFe-P@NC electrolyzer with low cell voltages of 1.77 V and 1.93 V could drive 100 mA cm^(−2) and 500 mA cm^(−2) in alkaline seawater electrolyte.Remarkably,a water-splitting device could be actuated efficiently by sustainable energies to facilitate a source of hydrogen energy.
基金financially supported by the National Natural Science Foundation of China(52174283)Shandong Provincial Natural Science Foundation(ZR2020MB044)+1 种基金Qingdao Science and Technology Benefiting People Special Project(20-3-4-8-nsh)Postgraduate Innovation Project of China University of Petroleum(YCX2021062).
文摘Inexpensive and accessible NiFe-based oxygen evolution reaction(OER)electrocatalysts show limitations for practical industrial applications owing to their activity and stability under industrial conditions.Herein,an FeNi_(2)S_(4)@NiFe–LDH heterostructure is constructed by the molten salt method and interfacial corrosion strategy,in which amorphous NiFe–LDH nanosheets grow in situ on the surface of crystalline FeNi_(2)S_(4) with a nanograss structure.The introduction of amorphous NiFe–LDH can not only optimize the adsorption energy of OER intermediates,but also significantly improve the overall stability and activity of the catalyst by reducing the loss of the S element in FeNi_(2)S_(4).At the same time,the OH^(−)produced by S ion hydrolysis can also promote the in situ construction of NiFe–LDH.Such an amorphous–crystalline structure gives full contribution to the advantages of each component,modulates the nanostructure,and promotes the electron transfer across the interfaces.Consequently,FeNi_(2)S_(4)@NiFe–LDH achieves large current density values of 500 and 1000 mA cm^(−2) for the OER at overpotentials of only 283 and 306 mV in 1 M KOH(25℃)without losing performance for at least 600 h at 500 mA cm^(−2).Under the simulated practical industrial test conditions(6 M KOH,70℃),the same current densities of 500 and 1000 mA cm^(−2) are delivered at the ultra-low overpotentials of 137 and 155 mV with long-term stability at high and low current densities.Such excellent catalyst performance shows its great industrial application prospects.This work also provides a strategy using Earth-abundant materials for realizing large-scale water splitting.
基金supported by the Center for Emergent Materials,an NSF-funded MRSEC under award no.DMR-1420451Partial support for transport measurements by M.R.S.was provided by AFOSR project no.FA9550-18-1-0335+1 种基金J.E.G.acknowledges the Camille and Henry Dreyfus Foundation for partial support.D.W.gratefully acknowledges the financial support by the German Science Foundation DFG Research Fellowship(WE6480/1)Y.W.and W.W.thank the Ohio Supercomputer Center for computer time under grant PAS0072.
文摘Layered honeycomb intermetallic phases have attracted considerable research interest due to the wide array of exciting physical properties inherent in these materials.Here,we follow the evolution in structure and electronic properties of a relatively unexplored material system,Sr_(1−x)Ca_(x)PdAs,as the hexagonal PdAs honeycomb layer in SrPdAs distorts into the orthorhombic CaPdAs structure.The Sr-rich compounds(x=0 to 1/3)form symmetric,hexagonal honeycomb PdAs layers,whereas in the Ca-rich region(x=1/2 to 1)the PdAs layers distort into an orthorhombic structure featuring long and short Pd–Pd distances.This dis tortion occurs when the average Pd–Pd distance falls below 4.21Å.All compounds are observed to exhibit metallic temperature-dependent resistivity trends.There are no apparent discontinuities indicative of metal-to-insulator transitions and the room temperature resistivity values range from 18 to 180 mΩcm.In total,this work maps out the structural and electronic phase diagram of Sr_(1−x)Cax PdAs compounds.
基金financially supported by National Natural Science Foundation of China(11575211,11875028)the Fundamental Research Funds for the Central Universities(2017MS044).
文摘The adsorption remediation of radioactive contamination from wastewater is scientifically and economically important.In this work,titanium dioxide-modified manganese dioxide(MnO_(2)@TiO_(2))was prepared by immobilizing crystalline anatase titanium dioxide(TiO_(2))on the surface of alpha manganese dioxide nanowire(MnO_(2)).The base material MnO_(2) nanowire acted as a physical template for the vip TiO_(2),and the formed MnO_(2)@TiO_(2) composite exhibited a highly uniform core–shell nanorod structure.The MnO_(2)@TiO_(2) composite was investigated as an efficient adsorbent for the removal of U(Ⅵ)from aqueous solution.In the same system,MnO_(2)@TiO_(2) exhibited a much higher maximum adsorption capacity(105.3 mg g^(−1))for U(Ⅵ)as compared with MnO_(2)(13.3 mg g^(−1)),showing that the performance of the surface-modified MnO_(2) was greatly improved.The fitting results for kinetic and isothermal models manifested that U(Ⅵ)ion adsorption by MnO_(2)@TiO_(2) involved monolayer chemisorption.Characterization before and after adsorption was performed and the results compared and analyzed carefully,with the conclusion that there might be three kinds of interactions between U(Ⅵ)and MnO_(2)@TiO_(2) during the adsorption process,namely inner-sphere surface complexation,chemical precipitation,and electrostatic interaction.The low-cost,facile fabrication method and efficient performance endow the adsorbent MnO_(2)@TiO_(2) with a high potential for U(Ⅵ)removal from actual wastewater.
基金support from the National Natural Science Foundation of China(91741105)Chongqing Municipal Natural Science Foundation(cstc2018jcyjAX0625).
文摘The electronic structure of a compound plays a key role in its functionality and hence its applications.The core-level X-ray spectroscopy technique at the metal L-edge is widely used for probing the valence electronic structure.The X-ray spectral features in the metal L-edge energy regime are usually complicated by a multitude of interactions,which make them challenging to interpret.The X-ray absorption spectra(XAS)and the resonant inelastic X-ray scattering(RIXS)spectra in the cobalt L-edge energy regime of tris(2,2’-bipyridine)cobalt compounds[Co^(Ⅱ)(bpy)3]^(2+)and[CoⅢ(bpy)3]3+are calculated using an ab initio restricted active space(RAS)approach.The experimental spectra are nicely reproduced and their spectral features are interpreted in terms of the orbital contributions and the final-state contributions.Unbiased assignments on the spin state of the ground state of these two cobalt compounds have been critically assessed through valence-excited state calculations and the fingerprints of the X-ray spectral features together with the calculations of the branching ratio.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea Government(MSIT)(Nos.RS-2023-00208355,RS-2023-00222166,RS-2024-00348205,RS-2024-00457040).
文摘This study presents the design and fabrication of a ruthenium dioxide(RuO_(2))nanosheets-functionalized tin dioxide(SnO_(2))thin-film gas sensor integrated with a microheater in a suspended membrane structure.The RuO_(2)nanosheets are synthesized via an intercalation-driven exfoliation process and subsequently deposited onto a sputtered SnO_(2)thin film.Due to the catalytic properties and high surface-to-volume ratio of RuO_(2)nanosheets,the functionalized sensor demonstrates a 337%increase in response(R_(air)/R_(gas))to 10 ppm ethanol compared to pristine SnO_(2)thin film.The sensor achieves sensitive detection from a few parts-per-million(ppm)down to several parts-per-billion(ppb)concentrations of ethanol.Evaluations under varied humidity conditions,as well as selectivity and 28-day stability tests,demonstrate that the RuO_(2)nanosheets-functionalized sensor maintains reliable performance.These results highlight its potential as a sensitive,selective,and low-power solution for ethanol gas detection.Furthermore,the sensor successfully tracks breath alcohol concentration in real-time through controlled alcohol intake experiments,demonstrating its feasibility for practical breath alcohol detection.
