Reduction Kinetics of Nickel Sulphide

Reduction kinetics of Ni_3S_2 was experimen- tally studied by following the time required for completion of the hydrogen reduction reaction in the presence of calcium oxide.A simple empirical integration equation,derived for describing the ef- fect of CaO/S molar ratio,temperature,hydrogen concentration and the average diameter of Ni_3S_2 grains,may be shown as following: t|_(X=1)=2.317×10^(-6)d_(Ni_3S_2) C_(H_2)^(-1) β^(-2.29)e^(13710/T),min The reduction reaction is of first order with respect to hydrogen concentration,and the apparent reac- tion activation energy is 114.0 kJ/mol.A great ma- jority of metallic Ni reduced from Ni_3S_2 is distrib- uted in the products evenly.

High-performance aqueous asymmetric supercapacitors based on the cathode of one-step electrodeposited cracked bark-shaped nickel manganese sulfides on activated carbon cloth

In this work,we report a high-performance self-standing supercapacitor electrode of mixed nickel manganese sulfides (NMSs)with a cracked-bark shape grown by one-step electrochemical deposition on activated carbon cloth (ACC).The electrode possesses outstanding electrochemical properties,including a high specific capacitance of up to 3142.8 F g^(-1)at 1.0 A g^(-1),the high-rate performance (~1206.8 F g^(-1)at 60.0 A g^(-1)),and cycle stability (~92.3%capacitance retention after 8000 cycles at8 A g^(-1)).An asymmetric supercapacitor assembled using NMSs on ACC as the cathode,activated carbon on carbon cloth as the anode and 1.0 mol L;KOH as the electrolyte delivers a high energy density of 111.2 W h kg^(-1)at 800.0 W kg^(-1)and the prominent cycling performance of~93.2%capacitance retention after 10000 cycles at 5 A g^(-1)with the Columbic efficiency of around 100%during these 10000 cycles.The high performance and facile preparation indicate that the NMSs on ACC hold a huge potential as the electrode for supercapacitors.

Waste cotton fabric derived porous carbon containing Fe_(3)O_(4)/NiS nanoparticles for electrocatalytic oxygen evolution

Developing low-cost,active and durable electrocatalysts for oxygen evolution reaction(OER)is an urgent task for the applications such as water splitting and rechargeable metal-air battery.Herein,this work reports the fabrication of a metal and hetero atom co-doped fibrous carbon structure derived from cotton textile wastes and its use as an efficient OER catalyst.The free-standing fibrous carbon structure,fabricated with a simple two-step carbonization process,has a high specific surface area of 1796 m^2/g and a uniform distribution of Fe_(3)O_(4)/NiS nanoparticles(Fe_(3)O_(4)/NiS@CC).The composite exhibits excellent OER performance with an onset potential of 1.44 V and a low overpotential of 310 mV at the current density of 10 mA/cm^2in a 1.0 M KOH solution,which even surpass commercial Ru O_(2)catalyst.Additionally,this ternary catalyst shows remarkable long-term stability without current density loss after continuous operation for 26 h.It can be believed that the outstanding OER performance is attributed to the synergistic effect between the iron oxides and nickel sulphides,as well as the micro-meso porous carbon structure.This study demonstrates a new strategy to use conventional textile materials to prepare highly efficient electrocatalysts;it also provides a simple approach to turn textile waste into valuable products.