Supercapacitors known as typical electrochemical capacitors have been considered as one of the most promising candidates of energy storage systems owing to their advantages such as high-power density,long life span an...Supercapacitors known as typical electrochemical capacitors have been considered as one of the most promising candidates of energy storage systems owing to their advantages such as high-power density,long life span and lower production cost.The electrode materials play a crucial role on properties of supercapacitors.Hence,many researches have been focused on the development of novel electrode materials for high-performance supercapacitors.NiCo_2O_4as supercapacitor electrode material has drawn more and more attentions in recent years due to its outstanding advantages,such as high theoretical capacity,low cost,natural abundance and easy of synthesis.However,the NiCo_2O_4always suffer from severe capacity deterioration because of the low electrical conductivity and small surface area.Hence,it is necessary to systematically and comprehensively summarize the progress in understanding and modifying NiCo_2O_4-based materials from various aspects.In this review,the structure and synthesis method of NiCo_2O_4-based materials are discussed in detail.And then,the major goal of this review is to highlight new progress in using proposed strategies to improve the cycling stability and rate capacity of NiCo_2O_4-based materials,including synthesis,control of special morphologies and design of composite materials.Finally,an insight into the future research and development of Ni Co_2O_4-based materials for supercapacitors is prospected.展开更多
In the quest for the development of thermally stable,highly active and low-cost catalysts for use in catalyzed diesel particulate filter,nano-composites are new areas of research.Therefore,we reported the easy synthes...In the quest for the development of thermally stable,highly active and low-cost catalysts for use in catalyzed diesel particulate filter,nano-composites are new areas of research.Therefore,we reported the easy synthesis of spinel NiCo_(2)O_(4)/perovskite LaCoO_(3) nano-composite,and its individual oxides NiCo_(2)O_(4)and LaCoO_(3) for comparison.The detailed insights into the physio-chemical characteristics of formed NiCo_(2)O_(4)/LaCoO_(3) nano-composite were done based on various characterization analysis such as X-ray diffraction(XRD),Fourier transform infrared(FT-IR),N_(2) physiosorption,scanning electron microscopy-energy dispersive spectroscopy(SEM-EDX),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The characterization analysis of NiCo_(2)O_(4)/LaCoO_(3) revealed the successful formation of a chemical interface possessing strong interfacial interaction,resulting in desirable physicochemical characteristics such as small crystallite size,abundant mesoporosity,high specific surface area and activation of surface lattice oxygen.Owing to the desirable characteristics,the activity results over NiCo_(2)O_(4)/LaCoO_(3) nano-composite showed the excellent CO oxidation performance and high soot oxidation activity,recyclability and thermal stability.This work mainly attempts to emphasize the effectiveness of the facile,inexpensive and conventionally used precipitation method for the successful formation of highly efficient nano-composites.展开更多
Sulfite (S(IV)) is a promising substitute for sulfate radical-based advanced oxidation processes.Here,a composite of in-situ anchoring Ni Co_(2)O_(4)nanosheets on biochar (BC) was firstly employed as a heterogeneous a...Sulfite (S(IV)) is a promising substitute for sulfate radical-based advanced oxidation processes.Here,a composite of in-situ anchoring Ni Co_(2)O_(4)nanosheets on biochar (BC) was firstly employed as a heterogeneous activator for sulfite (Ni Co_(2)O_(4)@BC-sulfite) to degrade atrazine (ATZ) in the neutral environment.The synergistic coupling of BC and Ni Co_(2)O_(4)endows the resulting composite excellent catalytic activity.82% of the degradation ratio of ATZ (1 mg/L) could be achieved within 10 min at initial concentrations of 0.6 g/L Ni Co_(2)O_(4)@BC,3.0 mmol/L sulfite in neutral environment.When further supplementing sulfite into the system at 20 min (considering the depletion of sulfite),outstanding degradation efficiency (100%) were achieved in the next 10 min without any other energy input by the Ni Co_(2)O_(4)@BC-sulfite system.The features of the prepared catalysts and the effects of some key parameters on ATZ degradation were systematically examined.A strong inner-sphere complexation (≡Co_(2)+/Ni^(2+)-SO_(3)^(2-)) was explored between sulfite and the metal sites on the Ni Co_(2)O_(4)@BC surface.The redox cycle of the surface metal efficiently mediated sulfite activation and triggered the series radical chain reactions.The generated radicals,in particular the surface-bound radicals were involved in ATZ degradation.High performance liquid chromatography-tandem mass spectrometry (LC-MS) technique was used to detect the degradation intermediates.Density functional theory (DFT) calculations were performed to illustrate the possible degradation pathways of ATZ.Finally,an underlying mechanism for ATZ removal was proposed.The present study offered a low-cost and sustainable catalyst for sulfite activation to remove ATZ in an environmentally friendly manner from wastewater.展开更多
Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile...Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.展开更多
The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays as...The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.展开更多
To find a novel counter electrode(CE)material for quantum dot-sensitized solar cells(QDSSCs),pompon-like NiCo_(2)O_(4) nanospheres are synthesized by a facile solvothermal and post-calcination method and we attempt to...To find a novel counter electrode(CE)material for quantum dot-sensitized solar cells(QDSSCs),pompon-like NiCo_(2)O_(4) nanospheres are synthesized by a facile solvothermal and post-calcination method and we attempt to apply it as a CE material for QDS SC.The catalytic performance of NiCo_(2)O_(4) counter electrode is investigated in detail through electrochemical impedance spectroscopy,Tafel test and cyclic voltammetry.The catalytic activity of NiCo_(2)O_(4) CE is superior to that of nanoflower-like Cu2S CE and traditional Cu2S/brass CE,which is mainly attributed to the large specific surface area,outstanding electrical conductivity of bimetallic oxides and the synergistic promotion effect of metals with different valence states.Under standard sunlight(air mass AM 1.5G 100 mW·cm^(-2)),the CdS/CdSe/ZnS-sensitized solar cell assembled with NiCo_(2)O_(4) CE achieved a photoelectric conversion efficiency of 5.55%,with a short current density of 22.49 mA·cm^(-2),an open circuit voltage of 0.574 V,and a fill factor of 0.43,which is slightly higher than the QDSSCs with nanoflower-like Cu_(2)S CE(4.75%)and traditional Cu_(2)S/brass CE(4.69%).This research provides ideas for discovering innovative and efficient CE materials for QDSSCs.展开更多
基金financially supported by the National Natural Science Foundation of China (nos. 51774002 and 51672156)Anhui Provincial Science Fund for Excellent Young Scholars (no. gxyqZD2016066)+2 种基金the National Key Basic Research Program of China (2014CB932400)Guangdong special support program (2015TQ01N401)Shenzhen Technical Plan Project (KQJSCX20160226191136)
文摘Supercapacitors known as typical electrochemical capacitors have been considered as one of the most promising candidates of energy storage systems owing to their advantages such as high-power density,long life span and lower production cost.The electrode materials play a crucial role on properties of supercapacitors.Hence,many researches have been focused on the development of novel electrode materials for high-performance supercapacitors.NiCo_2O_4as supercapacitor electrode material has drawn more and more attentions in recent years due to its outstanding advantages,such as high theoretical capacity,low cost,natural abundance and easy of synthesis.However,the NiCo_2O_4always suffer from severe capacity deterioration because of the low electrical conductivity and small surface area.Hence,it is necessary to systematically and comprehensively summarize the progress in understanding and modifying NiCo_2O_4-based materials from various aspects.In this review,the structure and synthesis method of NiCo_2O_4-based materials are discussed in detail.And then,the major goal of this review is to highlight new progress in using proposed strategies to improve the cycling stability and rate capacity of NiCo_2O_4-based materials,including synthesis,control of special morphologies and design of composite materials.Finally,an insight into the future research and development of Ni Co_2O_4-based materials for supercapacitors is prospected.
文摘In the quest for the development of thermally stable,highly active and low-cost catalysts for use in catalyzed diesel particulate filter,nano-composites are new areas of research.Therefore,we reported the easy synthesis of spinel NiCo_(2)O_(4)/perovskite LaCoO_(3) nano-composite,and its individual oxides NiCo_(2)O_(4)and LaCoO_(3) for comparison.The detailed insights into the physio-chemical characteristics of formed NiCo_(2)O_(4)/LaCoO_(3) nano-composite were done based on various characterization analysis such as X-ray diffraction(XRD),Fourier transform infrared(FT-IR),N_(2) physiosorption,scanning electron microscopy-energy dispersive spectroscopy(SEM-EDX),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The characterization analysis of NiCo_(2)O_(4)/LaCoO_(3) revealed the successful formation of a chemical interface possessing strong interfacial interaction,resulting in desirable physicochemical characteristics such as small crystallite size,abundant mesoporosity,high specific surface area and activation of surface lattice oxygen.Owing to the desirable characteristics,the activity results over NiCo_(2)O_(4)/LaCoO_(3) nano-composite showed the excellent CO oxidation performance and high soot oxidation activity,recyclability and thermal stability.This work mainly attempts to emphasize the effectiveness of the facile,inexpensive and conventionally used precipitation method for the successful formation of highly efficient nano-composites.
基金supported by the National Science Foundation of China (Nos.22076057,21777052)the National Key R&D Program of China (No.2018YFC1802003)+1 种基金the Project for Application Foundation Frontier for Wuhan (No.2019020701011486)The Program of Introducing Talents of Discipline to Universities of China (111 program,B17019)。
文摘Sulfite (S(IV)) is a promising substitute for sulfate radical-based advanced oxidation processes.Here,a composite of in-situ anchoring Ni Co_(2)O_(4)nanosheets on biochar (BC) was firstly employed as a heterogeneous activator for sulfite (Ni Co_(2)O_(4)@BC-sulfite) to degrade atrazine (ATZ) in the neutral environment.The synergistic coupling of BC and Ni Co_(2)O_(4)endows the resulting composite excellent catalytic activity.82% of the degradation ratio of ATZ (1 mg/L) could be achieved within 10 min at initial concentrations of 0.6 g/L Ni Co_(2)O_(4)@BC,3.0 mmol/L sulfite in neutral environment.When further supplementing sulfite into the system at 20 min (considering the depletion of sulfite),outstanding degradation efficiency (100%) were achieved in the next 10 min without any other energy input by the Ni Co_(2)O_(4)@BC-sulfite system.The features of the prepared catalysts and the effects of some key parameters on ATZ degradation were systematically examined.A strong inner-sphere complexation (≡Co_(2)+/Ni^(2+)-SO_(3)^(2-)) was explored between sulfite and the metal sites on the Ni Co_(2)O_(4)@BC surface.The redox cycle of the surface metal efficiently mediated sulfite activation and triggered the series radical chain reactions.The generated radicals,in particular the surface-bound radicals were involved in ATZ degradation.High performance liquid chromatography-tandem mass spectrometry (LC-MS) technique was used to detect the degradation intermediates.Density functional theory (DFT) calculations were performed to illustrate the possible degradation pathways of ATZ.Finally,an underlying mechanism for ATZ removal was proposed.The present study offered a low-cost and sustainable catalyst for sulfite activation to remove ATZ in an environmentally friendly manner from wastewater.
基金financially supported by the National Natural Science Foundation of China(No.22072069)the Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials(Wuhan University of Science and Technology No.WKDM202303).
文摘Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.
基金This work was supported by the Natural Science Foundation of China(51962032,61704114,and 51764049)the Youth Innovative Talents Cultivation Fund,Shihezi University(KX01480109)the Opening Project of The Research Center for Material Chemical Engineering Technology of Xinjiang Bingtuan(2017BTRC007).
文摘The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.
基金financially supported by the Natural Science Foundation of China(Grant Nos.22071018 and 21671035)。
文摘To find a novel counter electrode(CE)material for quantum dot-sensitized solar cells(QDSSCs),pompon-like NiCo_(2)O_(4) nanospheres are synthesized by a facile solvothermal and post-calcination method and we attempt to apply it as a CE material for QDS SC.The catalytic performance of NiCo_(2)O_(4) counter electrode is investigated in detail through electrochemical impedance spectroscopy,Tafel test and cyclic voltammetry.The catalytic activity of NiCo_(2)O_(4) CE is superior to that of nanoflower-like Cu2S CE and traditional Cu2S/brass CE,which is mainly attributed to the large specific surface area,outstanding electrical conductivity of bimetallic oxides and the synergistic promotion effect of metals with different valence states.Under standard sunlight(air mass AM 1.5G 100 mW·cm^(-2)),the CdS/CdSe/ZnS-sensitized solar cell assembled with NiCo_(2)O_(4) CE achieved a photoelectric conversion efficiency of 5.55%,with a short current density of 22.49 mA·cm^(-2),an open circuit voltage of 0.574 V,and a fill factor of 0.43,which is slightly higher than the QDSSCs with nanoflower-like Cu_(2)S CE(4.75%)and traditional Cu_(2)S/brass CE(4.69%).This research provides ideas for discovering innovative and efficient CE materials for QDSSCs.
