Aqueous aluminum ion batteries(AAIBs)have garnered extensive attention due to their environmental friendliness,high theoretical capacity,and low cost.However,the sluggish reaction kinetics and severe structural collap...Aqueous aluminum ion batteries(AAIBs)have garnered extensive attention due to their environmental friendliness,high theoretical capacity,and low cost.However,the sluggish reaction kinetics and severe structural collapse of the cathode material,especially manganese oxide,during the cycling process have hindered its further application.Herein,Cu^(2+)pre-interca la ted layeredδ-MnO_(2)was synthesized via a hydrothermal method.The pre-intercalated Cu^(2+)ions not only improve the conductivity of MnO_(2)cathode but also stabilize the structure to enhance stability.X-ray absorption fine structure(XAFS)combined with density functional theory(DFT)calculations confirm the formation of the covalent bond between Cu and O,increasing the electronegativity of O atoms and enhancing the H^(+)adsorption energy.Moreover,ex-situ measurements not only elucidate the Al^(3+)/H^(+)co-insertion energy storage mechanism but also demonstrate the high reversibility of the Cu-MnO_(2)cathode during cycling.This work provides a promising modification approach for the application of manganese oxides in AAIBs.展开更多
In this study,the effect of Cu^(2+)on the cassiterite and calcite flotation using octanohydroxamic acid(OHA)as collector was investigated through flotation tests,solution reaction tests and calculation,zeta potential ...In this study,the effect of Cu^(2+)on the cassiterite and calcite flotation using octanohydroxamic acid(OHA)as collector was investigated through flotation tests,solution reaction tests and calculation,zeta potential measurements,XPS analysis and residual reagent concentration measurements.Results indicated that Cu^(2+)played an activation role on cassiterite flotation but a depression role on calcite flotation.The copper cations were adsorbed on the cassiterite surface by forming a Cu—O bond,and the pre-adsorbed copper cations and the OHA-Cu complexes promoted the adsorption of OHA on the cassiterite surface.Thus,cassiterite flotation was activated.The dissolved HCO_(3)-in the calcite pulp underwent a double hydrolysis reaction with copper cations(Cu^(2+),CuOH^(+),Cu_(2)(OH)_(2)^(2+)and Cu_(3)(OH)_(4)^(2+))to form CuCO_(3).Some copper cations were adsorbed on the calcite surface as well,but some adsorbed Cu^(2+)on the calcite surface was desorbed by bonding with OHA,and most of OHA was consumed by Cu^(2+),basic copper carbonate and copper hydroxide.The residual OHA in the pulp was not sufficient for flotation,so calcite flotation was depressed.Finally,a model of the reaction mechanism of Cu^(2+)and OHA on the cassiterite and calcite surfaces was established.展开更多
The electrochemical carbon dioxide reduction reaction(CO_(2)RR)to high value-added fuels or chemicals driven by the renewable energy is promising to alleviate global warming.However,the selective CO_(2)reduction to C_...The electrochemical carbon dioxide reduction reaction(CO_(2)RR)to high value-added fuels or chemicals driven by the renewable energy is promising to alleviate global warming.However,the selective CO_(2)reduction to C_(2)products remains challenge.Cu-based catalyst with the specific Cu^(0)and Cu^(+)sites is important to generate C_(2)products.This work used nitrogen(N)to tune amounts of Cu^(0)and Cu^(+)sites in Cu_(2)O catalysts and improve C_(2)-product conversion.The controllable Cu^(0)/Cu^(+)ratio of Cu_(2)O catalyst from 0.16 to 15.19 was achieved by adjusting the N doping amount using NH3/Ar plasma treatment.The major theme of this work was clarifying a volcano curve of the ethylene Faraday efficiency as a function of the Cu^(0)/Cu^(+)ratio.The optimal Cu^(0)/Cu^(+)ratio was determined as 0.43 for selective electroreduction CO_(2)to ethylene.X-ray spectroscopy and density functional theory(DFT)calculations were employed to elucidate that the strong interaction between N and Cu increased the binding energy of N–Cu bond and stabilize Cu^(+),resulting in a 92.3%reduction in the potential energy change for^(∗)CO-^(∗)CO dimerization.This study is inspiring in designing high performance electrocatalysts for CO_(2)conversion.展开更多
The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insuffic...The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insufficient Cu^(+)/Cu^(0)active sites lead to their limited selectivity and stability for C_(2+)production.Herein,we embedded copper oxide(CuO_(x))particles into porous nitrogen-doped carbon nanofibers(CuO_(x)@PCNF)by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu_(2)O particles.The porous nitrogendoped carbon nanofibers protected and dispersed Cu^(+)species,and its micro porous structure enhanced the interaction between CuO_(x)and reactants during eCO_(2)RR.The obtained CuO_(x)@PCNF created more effective and stable Cu^(+)/Cu^(0)active sites.It showed a high Faradaic efficiency of 62.5%for C_(2+)products in Hcell,which was 2 times higher than that of bare CuO_(x)(~31.1%).Furthermore,it achieved a maximum Faradaic efficiency of 80.7%for C_(2+)products in flow cell.In situ characterization and density functional theory(DFT)calculation confirmed that the N-doped carbon layer protected Cu^(+)from electrochemical reduction and lowered the energy barrier for the dimerization of^(*)CO.Stable and exposed Cu^(+)/Cu^(0)active sites enhanced the enrichment of^(*)CO and promoted the C-C coupling reaction on the catalyst surface,which facilitated the formation of C_(2+)products.展开更多
基金financially supported by the National Natural Science Foundation of China(52102233)Science and Technology Project of Hebei Education Department(QN2023019)。
文摘Aqueous aluminum ion batteries(AAIBs)have garnered extensive attention due to their environmental friendliness,high theoretical capacity,and low cost.However,the sluggish reaction kinetics and severe structural collapse of the cathode material,especially manganese oxide,during the cycling process have hindered its further application.Herein,Cu^(2+)pre-interca la ted layeredδ-MnO_(2)was synthesized via a hydrothermal method.The pre-intercalated Cu^(2+)ions not only improve the conductivity of MnO_(2)cathode but also stabilize the structure to enhance stability.X-ray absorption fine structure(XAFS)combined with density functional theory(DFT)calculations confirm the formation of the covalent bond between Cu and O,increasing the electronegativity of O atoms and enhancing the H^(+)adsorption energy.Moreover,ex-situ measurements not only elucidate the Al^(3+)/H^(+)co-insertion energy storage mechanism but also demonstrate the high reversibility of the Cu-MnO_(2)cathode during cycling.This work provides a promising modification approach for the application of manganese oxides in AAIBs.
基金Project(52074355)supported by the National Natural Science Foundation of ChinaProject(2023JJ10070)supported by the Outstanding Youth Scientist Foundation of Hunan Province,China。
文摘In this study,the effect of Cu^(2+)on the cassiterite and calcite flotation using octanohydroxamic acid(OHA)as collector was investigated through flotation tests,solution reaction tests and calculation,zeta potential measurements,XPS analysis and residual reagent concentration measurements.Results indicated that Cu^(2+)played an activation role on cassiterite flotation but a depression role on calcite flotation.The copper cations were adsorbed on the cassiterite surface by forming a Cu—O bond,and the pre-adsorbed copper cations and the OHA-Cu complexes promoted the adsorption of OHA on the cassiterite surface.Thus,cassiterite flotation was activated.The dissolved HCO_(3)-in the calcite pulp underwent a double hydrolysis reaction with copper cations(Cu^(2+),CuOH^(+),Cu_(2)(OH)_(2)^(2+)and Cu_(3)(OH)_(4)^(2+))to form CuCO_(3).Some copper cations were adsorbed on the calcite surface as well,but some adsorbed Cu^(2+)on the calcite surface was desorbed by bonding with OHA,and most of OHA was consumed by Cu^(2+),basic copper carbonate and copper hydroxide.The residual OHA in the pulp was not sufficient for flotation,so calcite flotation was depressed.Finally,a model of the reaction mechanism of Cu^(2+)and OHA on the cassiterite and calcite surfaces was established.
基金supported by“Pioneer”and“Leading Goose”R&D Program of Zhejiang(Nos.2022C03146 and 2023C03017)the National Natural Science Foundation of China(Nos.U23A20677 and 22022610)+1 种基金Zhejiang Provincial Natural Science Foundation of China(No.LDT23E06015B06)the National Funded Postdoctoral Researcher Program of China(No.GZC20232363).
文摘The electrochemical carbon dioxide reduction reaction(CO_(2)RR)to high value-added fuels or chemicals driven by the renewable energy is promising to alleviate global warming.However,the selective CO_(2)reduction to C_(2)products remains challenge.Cu-based catalyst with the specific Cu^(0)and Cu^(+)sites is important to generate C_(2)products.This work used nitrogen(N)to tune amounts of Cu^(0)and Cu^(+)sites in Cu_(2)O catalysts and improve C_(2)-product conversion.The controllable Cu^(0)/Cu^(+)ratio of Cu_(2)O catalyst from 0.16 to 15.19 was achieved by adjusting the N doping amount using NH3/Ar plasma treatment.The major theme of this work was clarifying a volcano curve of the ethylene Faraday efficiency as a function of the Cu^(0)/Cu^(+)ratio.The optimal Cu^(0)/Cu^(+)ratio was determined as 0.43 for selective electroreduction CO_(2)to ethylene.X-ray spectroscopy and density functional theory(DFT)calculations were employed to elucidate that the strong interaction between N and Cu increased the binding energy of N–Cu bond and stabilize Cu^(+),resulting in a 92.3%reduction in the potential energy change for^(∗)CO-^(∗)CO dimerization.This study is inspiring in designing high performance electrocatalysts for CO_(2)conversion.
基金supported by the National Natural Science Foundation of China(22222601 and 22076019)the Fundamental Research Funds for the Central Universities(DUT23LAB611).
文摘The Cu^(+)/Cu^(0)sites of copper-based catalysts are crucial for enhancing the production of multicarbon(C_(2+))products from electrochemical CO_(2)reduction reaction(eCO_(2)RR).However,the unstable Cu^(+)and insufficient Cu^(+)/Cu^(0)active sites lead to their limited selectivity and stability for C_(2+)production.Herein,we embedded copper oxide(CuO_(x))particles into porous nitrogen-doped carbon nanofibers(CuO_(x)@PCNF)by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu_(2)O particles.The porous nitrogendoped carbon nanofibers protected and dispersed Cu^(+)species,and its micro porous structure enhanced the interaction between CuO_(x)and reactants during eCO_(2)RR.The obtained CuO_(x)@PCNF created more effective and stable Cu^(+)/Cu^(0)active sites.It showed a high Faradaic efficiency of 62.5%for C_(2+)products in Hcell,which was 2 times higher than that of bare CuO_(x)(~31.1%).Furthermore,it achieved a maximum Faradaic efficiency of 80.7%for C_(2+)products in flow cell.In situ characterization and density functional theory(DFT)calculation confirmed that the N-doped carbon layer protected Cu^(+)from electrochemical reduction and lowered the energy barrier for the dimerization of^(*)CO.Stable and exposed Cu^(+)/Cu^(0)active sites enhanced the enrichment of^(*)CO and promoted the C-C coupling reaction on the catalyst surface,which facilitated the formation of C_(2+)products.
