Recent developments in the synthesis of graphene-based structures focus on continuous improvement of porous nanostructures,doping of thin films,and mechanisms for the construction of threedimensional architectures.Her...Recent developments in the synthesis of graphene-based structures focus on continuous improvement of porous nanostructures,doping of thin films,and mechanisms for the construction of threedimensional architectures.Herein,we synthesize creeper-like Ni3Si2/NiOOH/graphene nanostructures via low-pressure all-solid meltingreconstruction chemical vapor deposition.In a carbon-rich atmosphere,high-energy atoms bombard the Ni and Si surface,and reduce the free energy in the thermodynamic equilibrium of solid Ni–Si particles,considerably catalyzing the growth of Ni–Si nanocrystals.By controlling the carbon source content,a Ni3Si2 single crystal with high crystallinity and good homogeneity is stably synthesized.Electrochemical measurements indicate that the nanostructures exhibit an ultrahigh specific capacity of 835.3 C g^−1(1193.28 F g^−1)at 1 A g^−1;when integrated as an all-solidstate supercapacitor,it provides a remarkable energy density as high as 25.9 Wh kg^−1 at 750 W kg^−1,which can be attributed to the freestanding Ni3Si2/graphene skeleton providing a large specific area and NiOOH inhibits insulation on the electrode surface in an alkaline solution,thereby accelerating the electron exchange rate.The growth of the high-performance composite nanostructure is simple and controllable,enabling the large-scale production and application of microenergy storage devices.展开更多
Although glucose electrochemical sensors based on enzymes play a dominant role in market,their stability remains a problem due to the inherent nature of enzymes.Therefore,glucose sensors that are independent on enzyme...Although glucose electrochemical sensors based on enzymes play a dominant role in market,their stability remains a problem due to the inherent nature of enzymes.Therefore,glucose sensors that are independent on enzymes have attracted more attention for the development of stable detection devices.Here we present an enzyme-free glucose sensor based on Ni(OH)_(2)and reduced graphene oxide(rGO).The as-fabricated sensor still exhibits excellent electrocatalytic activity for detecting glucose under enzyme independent conditions.The enhanced catalytic performance may due to synergistic effect as follows:(i)the interaction between the Ni2+andπelectron of graphene induces the formation of theβ-phase Ni(OH)_(2)with higher catalytic activity;(ii)the frozen dry process works as a secondary filtration,getting rid of poorly formed Ni(OH)_(2)particles with low catalytic activity;(iii)the rGO network with good conductivity provides a good electronic pathway for promoting electron transfer to reduce the response time.Based on the synergistic effect,the sensor exhibits a wide linear detection range from 0.2µmol/L to 1.0µmol/L and a low detection limit(0.1µmol/L,S/N=3).The excellent detection performance,as well as the easy and low-cost preparation method,suggests the promising applicability of the sensor in the glucose detection market.展开更多
以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/N...以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/Ni(OH)2的石墨烯又进行了层层堆积。电化学性能测试显示,电极材料GP/Ni-5性能最佳,其在电流密度为100 m A/g时,首次可逆比容量为1 287.4 m Ah/g,80次循环后比容量保持在830 m Ah/g,而纯Ni OOH/Ni(OH)2首次可逆比容量为2 400.6 m Ah/g,80次循环后比容量已降至405.9 m Ah/g,表明石墨烯的加入大大提高了材料的稳定性。展开更多
基金the Natural Science Basic Research Plan in Shaanxi Province of China(Program Nos.2019ZDLGY16-02,2019ZDLGY16-03,and 2019ZDLGY16-08)Youth Science and Technology Nova Program of Shaanxi Province(2020KJXX-068)the Wuhu and Xidian University special fund for industry-university-research cooperation(Program No.HX01201909039).
文摘Recent developments in the synthesis of graphene-based structures focus on continuous improvement of porous nanostructures,doping of thin films,and mechanisms for the construction of threedimensional architectures.Herein,we synthesize creeper-like Ni3Si2/NiOOH/graphene nanostructures via low-pressure all-solid meltingreconstruction chemical vapor deposition.In a carbon-rich atmosphere,high-energy atoms bombard the Ni and Si surface,and reduce the free energy in the thermodynamic equilibrium of solid Ni–Si particles,considerably catalyzing the growth of Ni–Si nanocrystals.By controlling the carbon source content,a Ni3Si2 single crystal with high crystallinity and good homogeneity is stably synthesized.Electrochemical measurements indicate that the nanostructures exhibit an ultrahigh specific capacity of 835.3 C g^−1(1193.28 F g^−1)at 1 A g^−1;when integrated as an all-solidstate supercapacitor,it provides a remarkable energy density as high as 25.9 Wh kg^−1 at 750 W kg^−1,which can be attributed to the freestanding Ni3Si2/graphene skeleton providing a large specific area and NiOOH inhibits insulation on the electrode surface in an alkaline solution,thereby accelerating the electron exchange rate.The growth of the high-performance composite nanostructure is simple and controllable,enabling the large-scale production and application of microenergy storage devices.
基金supported by the Beijing Natural Science Foundation,China(No.2232069)the National Natural Science Foundation of China(No.21875266).
文摘Although glucose electrochemical sensors based on enzymes play a dominant role in market,their stability remains a problem due to the inherent nature of enzymes.Therefore,glucose sensors that are independent on enzymes have attracted more attention for the development of stable detection devices.Here we present an enzyme-free glucose sensor based on Ni(OH)_(2)and reduced graphene oxide(rGO).The as-fabricated sensor still exhibits excellent electrocatalytic activity for detecting glucose under enzyme independent conditions.The enhanced catalytic performance may due to synergistic effect as follows:(i)the interaction between the Ni2+andπelectron of graphene induces the formation of theβ-phase Ni(OH)_(2)with higher catalytic activity;(ii)the frozen dry process works as a secondary filtration,getting rid of poorly formed Ni(OH)_(2)particles with low catalytic activity;(iii)the rGO network with good conductivity provides a good electronic pathway for promoting electron transfer to reduce the response time.Based on the synergistic effect,the sensor exhibits a wide linear detection range from 0.2µmol/L to 1.0µmol/L and a low detection limit(0.1µmol/L,S/N=3).The excellent detection performance,as well as the easy and low-cost preparation method,suggests the promising applicability of the sensor in the glucose detection market.
文摘以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/Ni(OH)2的石墨烯又进行了层层堆积。电化学性能测试显示,电极材料GP/Ni-5性能最佳,其在电流密度为100 m A/g时,首次可逆比容量为1 287.4 m Ah/g,80次循环后比容量保持在830 m Ah/g,而纯Ni OOH/Ni(OH)2首次可逆比容量为2 400.6 m Ah/g,80次循环后比容量已降至405.9 m Ah/g,表明石墨烯的加入大大提高了材料的稳定性。
