Heterogeneous advanced oxidation processes(AOPs)based on non-radical reactive species are considered as a powerful technology for wastewater purification due to their long half-lives and high adaptation in a wide pH r...Heterogeneous advanced oxidation processes(AOPs)based on non-radical reactive species are considered as a powerful technology for wastewater purification due to their long half-lives and high adaptation in a wide pH range.Herein,we fabricate surface Co defect-rich spinel ZnCo_(2)O_(4)porous nanosheets,which can generate≡CoIV=O and ^(1)O_(2) over a wide pH range of 3.81-10.96 by the formation of amphoteric≡Zn(OH)2 in peroxymonosulfate(PMS)activation process.Density functional theory(DFT)calculations show Co defect-rich ZnCo_(2)O_(4)possesses much stronger adsorption ability and more electron transfer to PMS.Moreover,the adsorption mode changes from terminal oxygen Co-O-Co to Co-O,accelerating the polarization of adjacent oxygen,which is beneficial to the generation of≡CoIV=O and Generating ^(1)O_(2) .Co defect-rich ZnCo_(2)O_(4)porous nanosheets exhibit highly active PMS activation activity and stability in p-nitrophenol(PNP)degradation,whose toxicity of degradation intermediates is significant reduction.The Co defect-rich ZnCo_(2)O_(4)nanosheet catalyst sponge/PMS system achieved stable and efficient removal of PNP with a removal efficiency higher than 93%over 10 h.This work highlights the development of functional catalyst and provides an atomic-level understanding into non-radical PMS activation process in wastewater treatment.展开更多
Constructing electrode materials with large capacity and good conductivity is an effective approach to improve the capacitor performance of asymmetric supercapacitors(ASCs).In this paper,ZnCo_(2)S_(4)core-shell nanosp...Constructing electrode materials with large capacity and good conductivity is an effective approach to improve the capacitor performance of asymmetric supercapacitors(ASCs).In this paper,ZnCo_(2)S_(4)core-shell nanospheres are constructed by two-step hydrothermal method.In order to improve the chemical activity of ZnCo_(2)S_(4),ZnCo_(2)S_(4)is activated using cetyltrimethylammonium bromide(CTAB).Then,MXene nanosheets are fixed on the surface of ZnCo_(2)S_(4)by electrostatic selfassembly method to improve the specific surface area of ZnCo_(2)S_(4)and MXene-wrapped ZnCo_(2)S_(4)composite is prepared in this work.Owing to the synergy effect between MXene nanosheets and ZnCo_(2)S_(4)core-shell nanospheres,the as-prepared composite displays fast ion transfer rate and charge/discharge process.The capacity of the MXenewrapped ZnCo_(2)S_(4)composite can reach 1072 F·g^(-1),which is far larger than that of ZnCo_(2)S_(4)(407 F·g^(-1))at 1 A·g^(-1).An ASC device is assembled,which delivers 1.7 V potential window and superior cyclic stability(95.41%capacitance retention).Furthermore,energy density of this device is up to 30.46 Wh·kg^(-1)at a power density of850 W·kg^(-1).The above results demonstrate that MXenewrapped ZnCo_(2)S_(4)composite has great application prospects in electrochemical energy storage field.展开更多
In this study,the hydrogen evolution performance of CdS nanorods is improved using ZnCo_(2)O_(4).ZnCo_(2)O_(4)nanospheres are synthesized using the hydrothermal and calcination methods,and CdS nanorods are synthesized...In this study,the hydrogen evolution performance of CdS nanorods is improved using ZnCo_(2)O_(4).ZnCo_(2)O_(4)nanospheres are synthesized using the hydrothermal and calcination methods,and CdS nanorods are synthesized using the solvothermal method.From the perspective of morphology,numerous CdS nanorods are anchored on the ZnCo_(2)O_(4)microspheres.According to the experimental results of photocatalytic hydrogen evolution,the final hydrogen evolution capacity of 7417.5μmol·g^(-1)·h^(-1)is slightly more than two times that of the single CdS,which proves the feasibility of our study.Through various characterization methods,it is proved that the composite sample has suitable optoelectronic properties.In addition,ZnCo_(2)O_(4)itself exhibits good conductivity and low impedance,which shortens the charge-transfer path.Overall,the introduction of ZnCo_(2)O_(4)expands the adsorption range of light and improves the performance of photocatalytic hydrogen evolution.This design can provide reference for developing high-efficiency photocatalysts.展开更多
Due to the involvement of four-electron transfer process at photoanode,water oxidation is the ratelimiting step in water splitting reaction.To settle this dilemma,ZnCo_(2)O_(4)nanoparticles are combined with BiVO_(4)t...Due to the involvement of four-electron transfer process at photoanode,water oxidation is the ratelimiting step in water splitting reaction.To settle this dilemma,ZnCo_(2)O_(4)nanoparticles are combined with BiVO_(4)to form a p-n ZnCo_(2)O_(4)/BiVO;heterojunction photoanode,which is proved by an input voltage-output current test.The built-in electric field formed within the heterojunction structure promotes the effective separation of electrons and holes.ZnCo_(2)O_(4)is also an effective water oxidation cocatalyst,since it could cause the holes entering the electrode/electrolyte interface rapidly for the subsequent water oxidation reaction.The photocurrent density of ZnCo_(2)O_(4)/BiVO_(4)composite photoanode reaches 3.0 mA/cm^(2) at 1.23 V vs.RHE in 0.5 mol/L sodium sulfate under AM 1.5 G simulated sunlight,about 2.1 times greater than that of BiVO_(4)(1.4 mA/cm^(2)).These results suggest the potential of ZnCo_(2)O_(4)nanoparticles for improving photoelectrochemical water splitting anode materials.展开更多
High performance microwave absorption(MA)materials especially those with tunable frequency are highly desirable for telecommunication industries and military camouflage in the information era.Herein,we constructed hie...High performance microwave absorption(MA)materials especially those with tunable frequency are highly desirable for telecommunication industries and military camouflage in the information era.Herein,we constructed hierarchical heterostructures based on VB-group laminated vanadium disulfide(VS_(2))nanosheets embedded with cobalt tetroxide(Co_(3)O_(4))nanoparticles.The highly dispersed Co_(3)O_(4)nanoparticles generate strong electromagnetic coupling networks that could enhance the loss properties of MA materials.Moreover,the interconnected VS_(2)layered network results in dipolar/interfacial polarization,multiple reflection and scattering favorable for the enhanced MA performance.Impressively,the maximum reflection loss of the VS_(2)/Co_(3)O_(4)hybrids containing 10%Co_(3)O_(4)can reach 57.96 dB at a thin thickness of 1.57 mm,and the bandwidth with an RL value less than-10 dB is as large as 3.5 GHz.The effective MA band could be adjusted in a range of 15.1 GHz(2.9-18 GHz)from S to Ku bands by the increase in thickness from 1.2 mm to 5.5 mm.The results show that the synergistic effect of multiple loss mechanisms and good impedance matching could be the reasons for strong MA capability in nearly all frequency bands,and thus,the high-performance and lightweight MA materials could be developed by the VS_(2)/Co_(3)O_(4)hybrids.展开更多
The two-dimensional(2D)nanosheet zinc cobaltate(ZnCo_(2)O_(4))was added into polyether block amide(Pebax)matrix to prepare mixing matrix membrane(MMM)for separating carbon dioxide(CO_(2))/methane(CH4)gas mixture.The 2...The two-dimensional(2D)nanosheet zinc cobaltate(ZnCo_(2)O_(4))was added into polyether block amide(Pebax)matrix to prepare mixing matrix membrane(MMM)for separating carbon dioxide(CO_(2))/methane(CH4)gas mixture.The 2D porous ZnCo_(2)O_(4)nanosheets were composed of chemically interconnected metal oxide nanoparticles.The ZnCo_(2)O_(4)nanoparticles in the nanosheets constructed large-quantity pores of 11.78 nm and provided abundant transfer channels for gas molecule.Moreover,the synergistic effect of bimetallic Zn^(2+)and Co^(2+)would promote the generation of oxygen vacancies(Oδ-),which could provide more CO_(2)(Cδ+)adsorption sites,thereby increased the selectivity of the membrane.The large aspect ratio of the ultra-thin ZnCo_(2)O_(4)nanosheets showed better dispersion in the membrane.The pure gas separation performance data showed the CO_(2)permeability and CO_(2)/CH4 selectivity of Pebax/ZnCo_(2)O_(4)membrane were 139.10 Barrer and 15.38,respectively,when the filling amount was 0.5 wt%.Compared with pure Pebax membrane,the separation performance(permeability and selectivity)were increased with 165.67%and 75.57%,respectively.展开更多
基金supported by the National Natural Science Foundation of China(50572051,50672041)National High-Tech Research and Development Program of China(863)(2006AA03Z218)National Key Basic Research Program of China(973)(2007CB607504)~~
基金supported by the National Natural Science Foundation of China(NSFC)(No.22308336).
文摘Heterogeneous advanced oxidation processes(AOPs)based on non-radical reactive species are considered as a powerful technology for wastewater purification due to their long half-lives and high adaptation in a wide pH range.Herein,we fabricate surface Co defect-rich spinel ZnCo_(2)O_(4)porous nanosheets,which can generate≡CoIV=O and ^(1)O_(2) over a wide pH range of 3.81-10.96 by the formation of amphoteric≡Zn(OH)2 in peroxymonosulfate(PMS)activation process.Density functional theory(DFT)calculations show Co defect-rich ZnCo_(2)O_(4)possesses much stronger adsorption ability and more electron transfer to PMS.Moreover,the adsorption mode changes from terminal oxygen Co-O-Co to Co-O,accelerating the polarization of adjacent oxygen,which is beneficial to the generation of≡CoIV=O and Generating ^(1)O_(2) .Co defect-rich ZnCo_(2)O_(4)porous nanosheets exhibit highly active PMS activation activity and stability in p-nitrophenol(PNP)degradation,whose toxicity of degradation intermediates is significant reduction.The Co defect-rich ZnCo_(2)O_(4)nanosheet catalyst sponge/PMS system achieved stable and efficient removal of PNP with a removal efficiency higher than 93%over 10 h.This work highlights the development of functional catalyst and provides an atomic-level understanding into non-radical PMS activation process in wastewater treatment.
基金financially supported by the Fundamental Research Funds for the Central Universities (No. 2019XKQYMS16)
文摘Constructing electrode materials with large capacity and good conductivity is an effective approach to improve the capacitor performance of asymmetric supercapacitors(ASCs).In this paper,ZnCo_(2)S_(4)core-shell nanospheres are constructed by two-step hydrothermal method.In order to improve the chemical activity of ZnCo_(2)S_(4),ZnCo_(2)S_(4)is activated using cetyltrimethylammonium bromide(CTAB).Then,MXene nanosheets are fixed on the surface of ZnCo_(2)S_(4)by electrostatic selfassembly method to improve the specific surface area of ZnCo_(2)S_(4)and MXene-wrapped ZnCo_(2)S_(4)composite is prepared in this work.Owing to the synergy effect between MXene nanosheets and ZnCo_(2)S_(4)core-shell nanospheres,the as-prepared composite displays fast ion transfer rate and charge/discharge process.The capacity of the MXenewrapped ZnCo_(2)S_(4)composite can reach 1072 F·g^(-1),which is far larger than that of ZnCo_(2)S_(4)(407 F·g^(-1))at 1 A·g^(-1).An ASC device is assembled,which delivers 1.7 V potential window and superior cyclic stability(95.41%capacitance retention).Furthermore,energy density of this device is up to 30.46 Wh·kg^(-1)at a power density of850 W·kg^(-1).The above results demonstrate that MXenewrapped ZnCo_(2)S_(4)composite has great application prospects in electrochemical energy storage field.
基金supported by the National Natural Science Foundation of China(Grant No.22062001)the graduate innovation project of North Minzu University(Grant No.YCX22166).
文摘In this study,the hydrogen evolution performance of CdS nanorods is improved using ZnCo_(2)O_(4).ZnCo_(2)O_(4)nanospheres are synthesized using the hydrothermal and calcination methods,and CdS nanorods are synthesized using the solvothermal method.From the perspective of morphology,numerous CdS nanorods are anchored on the ZnCo_(2)O_(4)microspheres.According to the experimental results of photocatalytic hydrogen evolution,the final hydrogen evolution capacity of 7417.5μmol·g^(-1)·h^(-1)is slightly more than two times that of the single CdS,which proves the feasibility of our study.Through various characterization methods,it is proved that the composite sample has suitable optoelectronic properties.In addition,ZnCo_(2)O_(4)itself exhibits good conductivity and low impedance,which shortens the charge-transfer path.Overall,the introduction of ZnCo_(2)O_(4)expands the adsorption range of light and improves the performance of photocatalytic hydrogen evolution.This design can provide reference for developing high-efficiency photocatalysts.
基金financially supported by the National Natural Science Foundation of China (Nos. 21808189 and 21663027)Natural Science Basic Research Fund of Shaanxi Province (No.2020JZ20)Fundamental Research Funds for the Central Universities of Chang’an University (No. 300102299304)。
文摘Due to the involvement of four-electron transfer process at photoanode,water oxidation is the ratelimiting step in water splitting reaction.To settle this dilemma,ZnCo_(2)O_(4)nanoparticles are combined with BiVO_(4)to form a p-n ZnCo_(2)O_(4)/BiVO;heterojunction photoanode,which is proved by an input voltage-output current test.The built-in electric field formed within the heterojunction structure promotes the effective separation of electrons and holes.ZnCo_(2)O_(4)is also an effective water oxidation cocatalyst,since it could cause the holes entering the electrode/electrolyte interface rapidly for the subsequent water oxidation reaction.The photocurrent density of ZnCo_(2)O_(4)/BiVO_(4)composite photoanode reaches 3.0 mA/cm^(2) at 1.23 V vs.RHE in 0.5 mol/L sodium sulfate under AM 1.5 G simulated sunlight,about 2.1 times greater than that of BiVO_(4)(1.4 mA/cm^(2)).These results suggest the potential of ZnCo_(2)O_(4)nanoparticles for improving photoelectrochemical water splitting anode materials.
基金supported by the National Natural Science Foundation of China(51772160 and 51977009)China Postdoctoral Science Foundation(Grant No.2020M682029)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905)。
文摘High performance microwave absorption(MA)materials especially those with tunable frequency are highly desirable for telecommunication industries and military camouflage in the information era.Herein,we constructed hierarchical heterostructures based on VB-group laminated vanadium disulfide(VS_(2))nanosheets embedded with cobalt tetroxide(Co_(3)O_(4))nanoparticles.The highly dispersed Co_(3)O_(4)nanoparticles generate strong electromagnetic coupling networks that could enhance the loss properties of MA materials.Moreover,the interconnected VS_(2)layered network results in dipolar/interfacial polarization,multiple reflection and scattering favorable for the enhanced MA performance.Impressively,the maximum reflection loss of the VS_(2)/Co_(3)O_(4)hybrids containing 10%Co_(3)O_(4)can reach 57.96 dB at a thin thickness of 1.57 mm,and the bandwidth with an RL value less than-10 dB is as large as 3.5 GHz.The effective MA band could be adjusted in a range of 15.1 GHz(2.9-18 GHz)from S to Ku bands by the increase in thickness from 1.2 mm to 5.5 mm.The results show that the synergistic effect of multiple loss mechanisms and good impedance matching could be the reasons for strong MA capability in nearly all frequency bands,and thus,the high-performance and lightweight MA materials could be developed by the VS_(2)/Co_(3)O_(4)hybrids.
基金the National High Technology Research and Development Program of China(2012AA03A611)the National Natural Science Foundation of China,grant No.21868031.
文摘The two-dimensional(2D)nanosheet zinc cobaltate(ZnCo_(2)O_(4))was added into polyether block amide(Pebax)matrix to prepare mixing matrix membrane(MMM)for separating carbon dioxide(CO_(2))/methane(CH4)gas mixture.The 2D porous ZnCo_(2)O_(4)nanosheets were composed of chemically interconnected metal oxide nanoparticles.The ZnCo_(2)O_(4)nanoparticles in the nanosheets constructed large-quantity pores of 11.78 nm and provided abundant transfer channels for gas molecule.Moreover,the synergistic effect of bimetallic Zn^(2+)and Co^(2+)would promote the generation of oxygen vacancies(Oδ-),which could provide more CO_(2)(Cδ+)adsorption sites,thereby increased the selectivity of the membrane.The large aspect ratio of the ultra-thin ZnCo_(2)O_(4)nanosheets showed better dispersion in the membrane.The pure gas separation performance data showed the CO_(2)permeability and CO_(2)/CH4 selectivity of Pebax/ZnCo_(2)O_(4)membrane were 139.10 Barrer and 15.38,respectively,when the filling amount was 0.5 wt%.Compared with pure Pebax membrane,the separation performance(permeability and selectivity)were increased with 165.67%and 75.57%,respectively.
