Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-...Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.展开更多
Developing multifunctional electrocatalysts with high catalytic activity,longterm stability,and low cost is essential for electrocatalytic energy conversion.Herein,sea urchinlike NiMoO_(4) nanorod arrays grown on nick...Developing multifunctional electrocatalysts with high catalytic activity,longterm stability,and low cost is essential for electrocatalytic energy conversion.Herein,sea urchinlike NiMoO_(4) nanorod arrays grown on nickel foam has been developed as a bifunctional electrocatalyst for urea oxidation and hydrogen evolution.The NiMoO_(4)‐200/NF catalyst exhibits efficient activity toward hydrogen evolution reaction with a low overpotential of only 68 mV in 1.0 mol/L KOH to gain a current density of 10 mA cm^(–2).The NiMoO_(4)‐300/NF catalyst exhibits a prominent oxygen evolution reaction(OER)catalytic activity with an overpotential of 288 mV at 50 mA cm^(–2),as well as for urea oxidation reaction with an ultralow potential of 1.36 V at 10 mA cm^(–2).The observed difference in electrocatalytic activity and selectivity,derived by temperature variation,is ascribed to different lattice oxygen contents.The lattice oxygen of NiMoO_(4)‐300/NF is more than that of NiMoO_(4)‐200/NF,and the lattice oxygen is conducive to the progress of OER.A urea electrolyzer was assembled with Ni‐MoO_(4)‐200/NF and NiMoO_(4)‐300/NF as cathode and anode respectively,delivering a current density of 10 mA cm^(–2)at a cell voltage of merely 1.38 V.The NiMoO_(4)nanorod arrays has also been successfully applied for photovoltage‐driven urea electrolysis and hydrogen production,revealing its great potential for solar‐driven energy conversion.展开更多
Nickel molybdate(NiMoO4)nanoparticles(NPs)were synthesized by sol-gel method.Utilizing water as solvent providescrystalline nanostructures.These nanocrystals were structurally characterized by X-ray diffraction,energy...Nickel molybdate(NiMoO4)nanoparticles(NPs)were synthesized by sol-gel method.Utilizing water as solvent providescrystalline nanostructures.These nanocrystals were structurally characterized by X-ray diffraction,energy dispersive X-ray analysis(EDX),and Fourier transform infrared spectra.Compositional stoichiometry was confirmed by EDX technique.The size and shapewere observed by scanning electron microscopy(SEM)and transmission electron microscope(TEM).It was found that the obtainedNPs were pure and single phase crystalline with monoclinic structure.The optical properties were studied by ultraviolet-visiblediffuse reflectance spectroscopy(UV-Vis-DRS)and photoluminescence(PL)measurements at room temperature.The magneticproperties were studied by vibrating sample magnetometer(VSM)and results showed superparamagnetic behavior of the obtainednanoparticles.Photocatalytic activity of NiMoO4was studied.The photocatalytic activity of NiMoO4was enhanced with the additionof TiO2.The catalysts NiMoO4,TiO2and NiMoO4-TiO2nanocomposites(NC)were tested for photocatalytic degradation(PCD)of4-chlorophenol(4-CP).It was found that PCD efficiency of NiMoO4-TiO2NC was higher than that of pure NiMoO4and TiO2.展开更多
In the recent development of electrochemical capacitors,battery-type electrode materials are considered to be promising materials owing to their comparable energy density and the ability to deliver significant power c...In the recent development of electrochemical capacitors,battery-type electrode materials are considered to be promising materials owing to their comparable energy density and the ability to deliver significant power compared to batteries.Herein,we report the applicability of nickel molybdate(NiMoO_(4))nanostructures as battery-type positive electrodes for the development of supercapatteries.The nickel molybdate nanostructures were synthesized by a facile coprecipitation technique and the structural and electrochemical properties were modified with appropriate heat treatment.The sample heat treated for 500℃ shows good crystallization of the NiMoO_(4) phase with a partial flower-like nanostructure compared with as-synthesized(bare)and 400℃ heat-treated samples.Moreover,the 500℃ sample-based electrode shows better battery-like electrochemical performances with a maximum specific capacity of 554 C g^(-1),which is higher compared to the other two electrodes.The supercapattery designed using the 500℃ NiMoO_(4) sample as the positive electrode and heteroatom enriched biowaste activated carbon as the negative electrode exhibited excellent electrochemical performances.The resultant supercapattery exhibited a maximum specific capacity value of 341 C g^(-1) at 1 A g^(-1) discharge specific current and showed an excellent specific energy of~64.07 W h kg^(-1) for a specific power of 0.676 kW kg^(-1) with<100%specific capacity retention even after 5000 charge/discharge cycles.展开更多
NiMoO4 has attracted intensive attention as one of the promising ternary metal oxides because of its high specific capacitance and electrical conductivity compared to traditional transition-metal oxides. In this study...NiMoO4 has attracted intensive attention as one of the promising ternary metal oxides because of its high specific capacitance and electrical conductivity compared to traditional transition-metal oxides. In this study, NiMoO4 nanorods uniformly decorated on graphene nanosheets （G-NiMoO4） are synthesized through a facile hydrothermal method. The prepared G-NiMoO4 composite exhibits a high specific capacitance of 714 C·g^-1 at 1 A·g^-1 and an excellent rate capability, with a retention ratio of 57.7% even at 100 A·g^-1. An asymmetric supercapacitor （ASC） fabricated with the G-NiMoO4 composite as the positive electrode and Fe2O3 quantum dot-decorated graphene （G-Fe2O3-QDs） as the negative electrode delivers an ultrahigh energy density of 130 Wh.kg^-1, which is comparable to those of previously reported aqueous NiMoO4-based ASCs. Even when the power density reaches 33.6 kW·kg^-1, an energy density of 56 Wh·kg^-1 can be maintained. The ASC device exhibits outstanding cycling stability, with a capacitance retention of 113% after 40,000 cycles. These results indicate that the G-NiMoO4 composite is a promising candidate for ASCs with ultrahigh energy density and excellent cycling stability. Moreover, the present work provides an exciting guideline for the future design of high-performance supercapacitors for industrial and consumer applications via the simultaneous use of various pseudocapacitive materials with suitable potential windows as the positive and negative electrodes.展开更多
The enhancement of energy density and cycling stability is in urgent need for the widespread applications of aqueous rechargeable Ni-Zn batteries.Herein,a facile strategy has been employed to construct hierarchical Co...The enhancement of energy density and cycling stability is in urgent need for the widespread applications of aqueous rechargeable Ni-Zn batteries.Herein,a facile strategy has been employed to construct hierarchical Co-doped NiMoO4nanosheets as the cathode for high-performance Ni-Zn battery.Benefiting from the merits of substantially improved electrical conductivity and increased concentration of oxygen vacancies,the NiMoO4with 15%cobalt doping(denoted as CNMO-15)displays the best capacity of 361.4 m A h g-1at a current density of 3 A g-1and excellent cycle stability.Moreover,the assembled CNMO-15//Zn battery delivers a satisfactory specific capacity of 270.9 mA h g-1at 2 A g-1and a remarkable energy density of 474.1 W h kg-1at 3.5 kW kg-1,together with a maximum power density of 10.3 kW kg-1achieved at 118.8 W h kg-1.Noticeably,there is no capacity decay with a 119.8%retention observed after 5000 cycles,demonstrating its outstanding long lifespan.This work might provide valuable inspirations for the fabrication of high-performance Ni-Zn batteries with superior energy density and impressive stability.展开更多
Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as...Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as a support to immobilize the active Pt component(Pt/NiMoO4)for catalytic formaldehyde elimination at low ambient temperature(15℃).The results showed that the hydrothermal preparation temperature and time had a noticeable impact on the morphology and catalytic activity of the samples.The catalyst prepared with hydrothermal temperature of 150℃for 4 hr(Pt-150-4)exhibited superior catalytic activity and stability mainly due to its distinctly porous structure,relative abundance of adsorbed surface hydroxyls/water,and high oxidation ability,which resulted from the interaction of Pt with Ni and Mo of the bimetallic NiMoO4 support.Our results might shed light on the rational design of multifunctional catalysts for removal of indoor air pollutants at low ambient temperature.展开更多
Electrocatalytic water splitting is a viable technique for generating hydrogen but is precluded from the sluggish kinetics of oxygen evolution reactions(OER).Small molecule oxidation reactions with lower working poten...Electrocatalytic water splitting is a viable technique for generating hydrogen but is precluded from the sluggish kinetics of oxygen evolution reactions(OER).Small molecule oxidation reactions with lower working potentials,such as methanol oxidation reactions,are good alternatives to OER with faster kinetics.However,the typically employed Ni-based electrocatalysts have poor activity and stability.Herein,a novel three-dimensional(3D)-networking Modoped Ni(OH)_(2) with ultralow Ni-Ni coordination is synthesized,which exhibits a high MOR activity of 100 mA cm^(−2) at 1.39 V,delivering 28 mV dec^(−1) for the Tafel slope.Meanwhile,hydrogen evolution with value-added formate co-generation is boosted with a current density of more than 500 mA cm^(−2) at a cell voltage of 2.00 V for 50 h,showing excellent stability in an industrial alkaline concentration(6 M KOH).Mechanistic studies based on density functional the-ory and X-ray absorption spectroscopy showed that the improved performance is mainly attributed to the ultralow Ni-Ni coordination,3D-networking structures and Mo dopants,which improve the catalytic activity,increase the active site density and strengthen the Ni(OH)_(2)3D-networking structures,respectively.This study paves a new way for designing electrocatalysts with enhanced activity and durability for industrial energy-saving hydrogen production.展开更多
基金supported by NSFC(21073235,21173270,21177160,21376261)863 Program(2013AA065302)PetroChina Innovation Foundation(2011D-5006-0403)
文摘Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.
文摘Developing multifunctional electrocatalysts with high catalytic activity,longterm stability,and low cost is essential for electrocatalytic energy conversion.Herein,sea urchinlike NiMoO_(4) nanorod arrays grown on nickel foam has been developed as a bifunctional electrocatalyst for urea oxidation and hydrogen evolution.The NiMoO_(4)‐200/NF catalyst exhibits efficient activity toward hydrogen evolution reaction with a low overpotential of only 68 mV in 1.0 mol/L KOH to gain a current density of 10 mA cm^(–2).The NiMoO_(4)‐300/NF catalyst exhibits a prominent oxygen evolution reaction(OER)catalytic activity with an overpotential of 288 mV at 50 mA cm^(–2),as well as for urea oxidation reaction with an ultralow potential of 1.36 V at 10 mA cm^(–2).The observed difference in electrocatalytic activity and selectivity,derived by temperature variation,is ascribed to different lattice oxygen contents.The lattice oxygen of NiMoO_(4)‐300/NF is more than that of NiMoO_(4)‐200/NF,and the lattice oxygen is conducive to the progress of OER.A urea electrolyzer was assembled with Ni‐MoO_(4)‐200/NF and NiMoO_(4)‐300/NF as cathode and anode respectively,delivering a current density of 10 mA cm^(–2)at a cell voltage of merely 1.38 V.The NiMoO_(4)nanorod arrays has also been successfully applied for photovoltage‐driven urea electrolysis and hydrogen production,revealing its great potential for solar‐driven energy conversion.
基金support from the Caplin Point Laboratories Limited,Chennai,India
文摘Nickel molybdate(NiMoO4)nanoparticles(NPs)were synthesized by sol-gel method.Utilizing water as solvent providescrystalline nanostructures.These nanocrystals were structurally characterized by X-ray diffraction,energy dispersive X-ray analysis(EDX),and Fourier transform infrared spectra.Compositional stoichiometry was confirmed by EDX technique.The size and shapewere observed by scanning electron microscopy(SEM)and transmission electron microscope(TEM).It was found that the obtainedNPs were pure and single phase crystalline with monoclinic structure.The optical properties were studied by ultraviolet-visiblediffuse reflectance spectroscopy(UV-Vis-DRS)and photoluminescence(PL)measurements at room temperature.The magneticproperties were studied by vibrating sample magnetometer(VSM)and results showed superparamagnetic behavior of the obtainednanoparticles.Photocatalytic activity of NiMoO4was studied.The photocatalytic activity of NiMoO4was enhanced with the additionof TiO2.The catalysts NiMoO4,TiO2and NiMoO4-TiO2nanocomposites(NC)were tested for photocatalytic degradation(PCD)of4-chlorophenol(4-CP).It was found that PCD efficiency of NiMoO4-TiO2NC was higher than that of pure NiMoO4and TiO2.
基金Creative Materials Discovery Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and Future(NRF-2015M3D1A1069710)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2014R1A6A1030419),Republic of Korea.
文摘In the recent development of electrochemical capacitors,battery-type electrode materials are considered to be promising materials owing to their comparable energy density and the ability to deliver significant power compared to batteries.Herein,we report the applicability of nickel molybdate(NiMoO_(4))nanostructures as battery-type positive electrodes for the development of supercapatteries.The nickel molybdate nanostructures were synthesized by a facile coprecipitation technique and the structural and electrochemical properties were modified with appropriate heat treatment.The sample heat treated for 500℃ shows good crystallization of the NiMoO_(4) phase with a partial flower-like nanostructure compared with as-synthesized(bare)and 400℃ heat-treated samples.Moreover,the 500℃ sample-based electrode shows better battery-like electrochemical performances with a maximum specific capacity of 554 C g^(-1),which is higher compared to the other two electrodes.The supercapattery designed using the 500℃ NiMoO_(4) sample as the positive electrode and heteroatom enriched biowaste activated carbon as the negative electrode exhibited excellent electrochemical performances.The resultant supercapattery exhibited a maximum specific capacity value of 341 C g^(-1) at 1 A g^(-1) discharge specific current and showed an excellent specific energy of~64.07 W h kg^(-1) for a specific power of 0.676 kW kg^(-1) with<100%specific capacity retention even after 5000 charge/discharge cycles.
文摘NiMoO4 has attracted intensive attention as one of the promising ternary metal oxides because of its high specific capacitance and electrical conductivity compared to traditional transition-metal oxides. In this study, NiMoO4 nanorods uniformly decorated on graphene nanosheets （G-NiMoO4） are synthesized through a facile hydrothermal method. The prepared G-NiMoO4 composite exhibits a high specific capacitance of 714 C·g^-1 at 1 A·g^-1 and an excellent rate capability, with a retention ratio of 57.7% even at 100 A·g^-1. An asymmetric supercapacitor （ASC） fabricated with the G-NiMoO4 composite as the positive electrode and Fe2O3 quantum dot-decorated graphene （G-Fe2O3-QDs） as the negative electrode delivers an ultrahigh energy density of 130 Wh.kg^-1, which is comparable to those of previously reported aqueous NiMoO4-based ASCs. Even when the power density reaches 33.6 kW·kg^-1, an energy density of 56 Wh·kg^-1 can be maintained. The ASC device exhibits outstanding cycling stability, with a capacitance retention of 113% after 40,000 cycles. These results indicate that the G-NiMoO4 composite is a promising candidate for ASCs with ultrahigh energy density and excellent cycling stability. Moreover, the present work provides an exciting guideline for the future design of high-performance supercapacitors for industrial and consumer applications via the simultaneous use of various pseudocapacitive materials with suitable potential windows as the positive and negative electrodes.
基金financially supported by the National Natural Science Foundation of China(51602049)the Fundamental Research Funds for the Central Universities(2232017D-15,GSIF-DH-M-2020002)China Postdoctoral Science Foundation(2017M610217 and 2018T110322)。
文摘The enhancement of energy density and cycling stability is in urgent need for the widespread applications of aqueous rechargeable Ni-Zn batteries.Herein,a facile strategy has been employed to construct hierarchical Co-doped NiMoO4nanosheets as the cathode for high-performance Ni-Zn battery.Benefiting from the merits of substantially improved electrical conductivity and increased concentration of oxygen vacancies,the NiMoO4with 15%cobalt doping(denoted as CNMO-15)displays the best capacity of 361.4 m A h g-1at a current density of 3 A g-1and excellent cycle stability.Moreover,the assembled CNMO-15//Zn battery delivers a satisfactory specific capacity of 270.9 mA h g-1at 2 A g-1and a remarkable energy density of 474.1 W h kg-1at 3.5 kW kg-1,together with a maximum power density of 10.3 kW kg-1achieved at 118.8 W h kg-1.Noticeably,there is no capacity decay with a 119.8%retention observed after 5000 cycles,demonstrating its outstanding long lifespan.This work might provide valuable inspirations for the fabrication of high-performance Ni-Zn batteries with superior energy density and impressive stability.
基金supported by the National Natural Science Foundation of China(Nos.21577046 and 21871111)Wuhan Morning Light plan of Youth Science and Technology(No.2017050304010327)
文摘Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as a support to immobilize the active Pt component(Pt/NiMoO4)for catalytic formaldehyde elimination at low ambient temperature(15℃).The results showed that the hydrothermal preparation temperature and time had a noticeable impact on the morphology and catalytic activity of the samples.The catalyst prepared with hydrothermal temperature of 150℃for 4 hr(Pt-150-4)exhibited superior catalytic activity and stability mainly due to its distinctly porous structure,relative abundance of adsorbed surface hydroxyls/water,and high oxidation ability,which resulted from the interaction of Pt with Ni and Mo of the bimetallic NiMoO4 support.Our results might shed light on the rational design of multifunctional catalysts for removal of indoor air pollutants at low ambient temperature.
基金We gratefully thank the financial support from the National Natural Science Foundation of China(22272108,21975163 and 22003041)Shenzhen Science and Technology Program(No.KQTD20190929173914967,JCYJ20200109110416441)the Senior Talent Research Start-up Fund of Shenzhen University(000263 and 000265).
文摘Electrocatalytic water splitting is a viable technique for generating hydrogen but is precluded from the sluggish kinetics of oxygen evolution reactions(OER).Small molecule oxidation reactions with lower working potentials,such as methanol oxidation reactions,are good alternatives to OER with faster kinetics.However,the typically employed Ni-based electrocatalysts have poor activity and stability.Herein,a novel three-dimensional(3D)-networking Modoped Ni(OH)_(2) with ultralow Ni-Ni coordination is synthesized,which exhibits a high MOR activity of 100 mA cm^(−2) at 1.39 V,delivering 28 mV dec^(−1) for the Tafel slope.Meanwhile,hydrogen evolution with value-added formate co-generation is boosted with a current density of more than 500 mA cm^(−2) at a cell voltage of 2.00 V for 50 h,showing excellent stability in an industrial alkaline concentration(6 M KOH).Mechanistic studies based on density functional the-ory and X-ray absorption spectroscopy showed that the improved performance is mainly attributed to the ultralow Ni-Ni coordination,3D-networking structures and Mo dopants,which improve the catalytic activity,increase the active site density and strengthen the Ni(OH)_(2)3D-networking structures,respectively.This study paves a new way for designing electrocatalysts with enhanced activity and durability for industrial energy-saving hydrogen production.
