Hierarchical molybdenum disulfide nanosheet arrays stemmed from nickel-cobalt layered double hydroxide/carbon cloth for highly-efficient hydrogen evolution reaction

The hierarchical structure of molybdenum disulfide(MoS2)nanosheet arrays stemmed from nickelcobalt layered double hydroxide(NiCo-LDH)/carbon cloth was prepared by growing the MoS_(2) nanosheet arrays onto the NiCo-LDH template which was pre-deposited onto the carbon cloth substrate.In this electrode configuration,carbon cloth is the three dimensional and conductive skeleton;NiCo-LDH nanosheets,as the template,ensure the oriented growth of MoS2 nanosheet arrays.Therefore,more MoS_(2) active sites are exposed and the catalyst exhibits good hydrogen evolution reaction activity.

Hierarchical CuCo_2O_4@nickel-cobalt hydroxides core/shell nanoarchitectures for high-performance hybrid supercapacitors

Ni0.5Co0.5（OH）2 nanosheets coated CuCo2O4 nanoneedles arrays were successfully designed and synthe- sized on carbon fabric. The core/shell nanoarchitectures directly served as the binder-free electrode with a superior capacity of 295.6 mAh g-1 at 1 Ag-1, which still maintained 220 mAh g-1 even at the high current density of 40 A g-l, manifesting their enormous potential in hybrid supercapacitor devices. The asassembled CuCo2O4@Ni0.5Co0.5（OH）2]]AC hybrid supercapacitor device exhibited favorable properties with the specific capacitance as high as 90 F g 1 at 1 A g-1 and the high energy density of 32 Wh kg 1 at the power density of 800 Wkg-1. Furthermore, the as-assembled device also delivered excellent cycling performance （retaining 91.9% of the initial capacitance after 12,000 cycles at 8 A g 1） and robust mechanical stability and flexibility, implying the huge potential of present hierarchical electrodes in energy storage devices.

Revisiting the anodic stability of nickel-cobalt hydroxide/carbon composite electrodes for rechargeable Ni-Zn battery

Aqueous rechargeable Ni−Zn batteries are considered as a new generation of safe and reliable electro-chemical energy storage system.However,low electronic conductivity of Ni-based cathodes hinders the practical application of Ni-Zn batteries.This problem can be overcome by compositing the Ni-based cath-ode with highly conductive carbon substrates.A chemical oxidation pre-treatment is popularly applied to the carbon substrates to increase their hydrophilicity and thus facilitate the growth of active materials in aqueous systems.However,the anodic stability of the oxidized carbon substrates is greatly challenged,which has never been addressed in previous reports.In this work,we first compared the anodic stabil-ity of carbon fiber paper with and without oxidation treatment and find that carbon substrate with the chemical treatment caused remarkable oxidization current in the required voltage range.To take both anodic stability and fine growth of active materials into account,here we demonstrated a facile physical surface-treatment method of ethanol wetting to replace the chemical treatment.The ethanol infiltration removes gas adsorption on carbon substrates and thus promotes their hydrophilicity.This cost-effective strategy simultaneously achieves a high anodic stability and a fine growth and uniform distribution of nickel-cobalt hydroxide on the carbon microfibers.The resulting Ni-Zn battery provides a high discharge capacity of 219 mAh/g with an operation cell voltage of 1.75 V.

Hierarchically porous cellulose nanofibril aerogel decorated with polypyrrole and nickel-cobalt layered double hydroxide for high-performance nonenzymatic glucose sensors

With increasing emphasis on green chemistry,biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials.Herein,a new pore-rich cellulose nanofibril aerogel is utilized as a substrate to integrate highly conductive polypyrrole and active nanoflower-like nickel-cobalt layered double hydroxide through in situ chemical polymerization and electrodeposition.This ternary composite can act as an effective self-supported electrode for the electrocatalytic oxidation of glucose.With the synergistic effect of three heterogeneous components,the electrode achieves outstanding glucose sensing performance,including a high sensitivity(851.4μA·mmol^(−1)·L·cm^(−2)),a short response time(2.2 s),a wide linear range(two stages:0.001−8.145 and 8.145−35.500 mmol·L^(−1)),strong immunity to interference,outstanding intraelectrode and interelectrode reproducibility,a favorable toxicity resistance(Cl^(‒)),and a good long-term stability(maintaining 86.0%of the original value after 30 d).These data are superior to those of some traditional glucose sensors using nonbiomass substrates.When determining the blood glucose level of a human serum,this electrode realizes a high recovery rate of 97.07%–98.89%,validating the potential for highperformance blood glucose sensing.