A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-...A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-rods(NRs)were prepared by growing them directly on carbon cloth(CC)via a simple hydrothermal reaction coupled with an annealing treatment.The resulting NiMoO_(4)-NR/CC-x composites served directly as electrodes for electrolysis of an alkaline medium and a simulated sea water.The results indicated that among the NiMoO_(4)-NR/CC-x composites,the NiMoO_(4)-NR/CC-10 composite possessed the highest HER activity with an overpotential of 244.8 mV at 10 mA/cm^(2),a Tafel slope of 95 mV/dec,the fastest charge transfer rate(R_(ct)<1Ω)and good stability in alkaline media.Even in simulated seawater,the NiMoO_(4)-NR/CC-10 composite showed good stability.The outstanding HER activity and stability may originate from the strong interaction between Ni and Mo in the NiMoO_(4) NRs as well as the efficient charge transfer process and the rate of the HER due to the synergistic effect involving the CC and NiMoO_(4) NRs.展开更多
Nickel molybdate(NiMoO_(4))attracts superior hydrogen desorption behavior but noticeably poor for efficiently driving the hydrogen evolution reaction(HER)in alkaline media due to the sluggish water dissociation step.H...Nickel molybdate(NiMoO_(4))attracts superior hydrogen desorption behavior but noticeably poor for efficiently driving the hydrogen evolution reaction(HER)in alkaline media due to the sluggish water dissociation step.Herein,we successfully accelerate the water dissociation kinetics of NiMoO_(4)for prominent HER catalytic properties via simultaneous in situ interfacial engineering with molybdenum dioxide(MoO_(2))and doping with phosphorus(P).The as-synthesized P-doped NiMoO_(4)/MoO_(2)heterostructure nanorods exhibit outstanding HER performance with an extraordinary low overpotential of-23 m V at a current density of 10 m A cm^(-2),which is highly comparable to the performance of the state-of-art Pt/C coated on nickel foam(NF)catalyst.The density functional theory(DFT)analysis reveals the enhanced performance is attributed to the formation of MoO_(2)during the in situ epitaxial growth that substantially reduces the energy barrier of the Volmer pathway,and the introduction of P that provides efficient hydrogen desorption of Ni MoO_(2).This present work creates valuable insight into the utilization of interfacial and doping systems for hydrogen evolution catalysis and beyond.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
A large surface area with high active site exposure is desired for the nano-scaled electrocatalysts fabrica-tion.Herein,taking NiMoO_(4)nanorods for example,we demonstrated the advantages of the microwave-assisted hyd...A large surface area with high active site exposure is desired for the nano-scaled electrocatalysts fabrica-tion.Herein,taking NiMoO_(4)nanorods for example,we demonstrated the advantages of the microwave-assisted hydrothermal synthesis method compared to the traditional hydrothermal approaches.Both monoclinic structured NiMoO_(4)in the nanorods morphology are found for these samples but it is more time-saving and efficient in the Ni-Mo synergism for the catalyst obtained by microwave-assisted hydrothermal syntheses method.When evaluated for urea oxidation,the current density can reach 130.79 mA/cm^(2)at 1.54 V,about 2.4 times higher than that of the counterpart catalyst(54.08 mA/cm^(2)).Moreover,largely improved catalytic stability,catalytic kinetics and rapid charge transfer ability are found on the catalyst obtained by the microwave-assisted approach.The high catalytic performance can be at-tributed to the high surface area and active site exposure of NiMoO_(4)nanorods formed by microwave irradiation.Considering the less time,facile synthesis condition and efficient components synergism,the microwave-assisted hydrothermal synthesis method might work better for the nanostructure electrocata-lysts fabrication.展开更多
Hydroquinone(HQ)poses immeasurable risk to human health and the natural environment on the grounds of high toxicity of organic phenolic compounds.Herein,an innovative electrochemical sensor based on two-dimensional ni...Hydroquinone(HQ)poses immeasurable risk to human health and the natural environment on the grounds of high toxicity of organic phenolic compounds.Herein,an innovative electrochemical sensor based on two-dimensional nickel molybdate nanowires(NiMoO_(4)NWs)is constructed for the ultra-sensitive determination of HQ,which can provide useful reference for the human health and environment protection.Two-dimensional NiMoO_(4)NWs are prepared successfully through a facile hydrothermal reaction and annealing process.The obtained two-dimensional NiMoO_(4)NWs are characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),high-resolution TEM(HRTEM),energy-dispersive X-ray spectroscopy(EDS)mapping and X-ray photoelectron spectroscopy(XPS).The accurate contents of Ni and Mo have been characterized by inductively coupled plasma atomic emission spectroscopy(ICP-AES),confirming that the lower content of the nickel in NiMoO_(4)NWs possesses the higher catalytic activity of HQ.Under the optimized conditions,the constructed HQ sensor exhibits satisfactory electrocatalytic activity with a low detection limit of 0.0355μmol/L(S/N=3),a wide linear range of 0.05-4600μmol/L and sensitivity of 170.064μA/(mmol cm^(2)).The sensor has been successfully applied to the detection of HQ in rainwater,tap water,domestic sewage and drinking water samples with satisfactory recovery.At the same time,this sensor has excellent reproducibility,selectivity,and stability.The constructed sensor has potential practical application value and broad application prospect in human health and environmental monitoring.展开更多
文摘A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-rods(NRs)were prepared by growing them directly on carbon cloth(CC)via a simple hydrothermal reaction coupled with an annealing treatment.The resulting NiMoO_(4)-NR/CC-x composites served directly as electrodes for electrolysis of an alkaline medium and a simulated sea water.The results indicated that among the NiMoO_(4)-NR/CC-x composites,the NiMoO_(4)-NR/CC-10 composite possessed the highest HER activity with an overpotential of 244.8 mV at 10 mA/cm^(2),a Tafel slope of 95 mV/dec,the fastest charge transfer rate(R_(ct)<1Ω)and good stability in alkaline media.Even in simulated seawater,the NiMoO_(4)-NR/CC-10 composite showed good stability.The outstanding HER activity and stability may originate from the strong interaction between Ni and Mo in the NiMoO_(4) NRs as well as the efficient charge transfer process and the rate of the HER due to the synergistic effect involving the CC and NiMoO_(4) NRs.
基金supported by the National Natural Science Foundation of China(21875292 and 51902103)Hunan Provincial Natural Science Foundation(2019JJ50037 and 2021JJ30087)+1 种基金Natural Science Foundation of Guangdong Province(2020A1515010798)the Hunan Joint International Laboratory of Advanced Materials and Technology for Clean Energy(2020CB1007)。
文摘Nickel molybdate(NiMoO_(4))attracts superior hydrogen desorption behavior but noticeably poor for efficiently driving the hydrogen evolution reaction(HER)in alkaline media due to the sluggish water dissociation step.Herein,we successfully accelerate the water dissociation kinetics of NiMoO_(4)for prominent HER catalytic properties via simultaneous in situ interfacial engineering with molybdenum dioxide(MoO_(2))and doping with phosphorus(P).The as-synthesized P-doped NiMoO_(4)/MoO_(2)heterostructure nanorods exhibit outstanding HER performance with an extraordinary low overpotential of-23 m V at a current density of 10 m A cm^(-2),which is highly comparable to the performance of the state-of-art Pt/C coated on nickel foam(NF)catalyst.The density functional theory(DFT)analysis reveals the enhanced performance is attributed to the formation of MoO_(2)during the in situ epitaxial growth that substantially reduces the energy barrier of the Volmer pathway,and the introduction of P that provides efficient hydrogen desorption of Ni MoO_(2).This present work creates valuable insight into the utilization of interfacial and doping systems for hydrogen evolution catalysis and beyond.
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supported by the National Natural Science Foundation of China (Nos.21972124,21603041)funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsupport received at the Testing Center of Yangzhou University。
文摘A large surface area with high active site exposure is desired for the nano-scaled electrocatalysts fabrica-tion.Herein,taking NiMoO_(4)nanorods for example,we demonstrated the advantages of the microwave-assisted hydrothermal synthesis method compared to the traditional hydrothermal approaches.Both monoclinic structured NiMoO_(4)in the nanorods morphology are found for these samples but it is more time-saving and efficient in the Ni-Mo synergism for the catalyst obtained by microwave-assisted hydrothermal syntheses method.When evaluated for urea oxidation,the current density can reach 130.79 mA/cm^(2)at 1.54 V,about 2.4 times higher than that of the counterpart catalyst(54.08 mA/cm^(2)).Moreover,largely improved catalytic stability,catalytic kinetics and rapid charge transfer ability are found on the catalyst obtained by the microwave-assisted approach.The high catalytic performance can be at-tributed to the high surface area and active site exposure of NiMoO_(4)nanorods formed by microwave irradiation.Considering the less time,facile synthesis condition and efficient components synergism,the microwave-assisted hydrothermal synthesis method might work better for the nanostructure electrocata-lysts fabrication.
基金supported by the National Natural Science Foundation of China (21705103)the Applied Basic Research Project of Shanxi Province (202103021224251)+2 种基金Scientific and Technological Innovation Projects in Shanxi Universities (2019L0460)the Graduate Education Innovation Project of Shanxi Province (2021Y485)the 1331 Engineering of Shanxi Province
文摘Hydroquinone(HQ)poses immeasurable risk to human health and the natural environment on the grounds of high toxicity of organic phenolic compounds.Herein,an innovative electrochemical sensor based on two-dimensional nickel molybdate nanowires(NiMoO_(4)NWs)is constructed for the ultra-sensitive determination of HQ,which can provide useful reference for the human health and environment protection.Two-dimensional NiMoO_(4)NWs are prepared successfully through a facile hydrothermal reaction and annealing process.The obtained two-dimensional NiMoO_(4)NWs are characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),high-resolution TEM(HRTEM),energy-dispersive X-ray spectroscopy(EDS)mapping and X-ray photoelectron spectroscopy(XPS).The accurate contents of Ni and Mo have been characterized by inductively coupled plasma atomic emission spectroscopy(ICP-AES),confirming that the lower content of the nickel in NiMoO_(4)NWs possesses the higher catalytic activity of HQ.Under the optimized conditions,the constructed HQ sensor exhibits satisfactory electrocatalytic activity with a low detection limit of 0.0355μmol/L(S/N=3),a wide linear range of 0.05-4600μmol/L and sensitivity of 170.064μA/(mmol cm^(2)).The sensor has been successfully applied to the detection of HQ in rainwater,tap water,domestic sewage and drinking water samples with satisfactory recovery.At the same time,this sensor has excellent reproducibility,selectivity,and stability.The constructed sensor has potential practical application value and broad application prospect in human health and environmental monitoring.
