Preparation And Electrochemical Application Of Fe, Co, Ni-based Nanoarray Materials

In recent years,electrochemical methods have attracted more attention due to their simple operation and high accuracy.Electrode materials are the key to electrochemical methods.When the particle size of the electrode material reaches the nanometer scale,its optical,electrical,magnetic and other properties will show new characteristics.Fe,Co and Ni-based nanoarray materials have become the research hotspots of electrode materials due to their variable valence,abundant earth resources,large specific surface area and good electrical conductivity.The construction of Fe,Co and Ni-based nanoarray materials on the substrate can expose more active sites and achieve more efficient performance,so it has a broad application prospect.Currently,Fe,Co and Ni-based nanoarray materials have been applied in electrocatalysis,electrochemical sensing,medical and clinical fields.Based on the superior electrochemical performance of Fe,Co and Ni-based nanoarray materials,this paper successfully prepared FeS-NiS/Ti mesh（TM）and Fe-CoS₂/Carbon cloth（CC）nanosheet array as high-efficiency electrocatalyst for electrocatalytic oxygen evolution reaction（OER）and Co（Ni）-MOF nanosheet array for H₂O₂electrochemical sensing.The main contents are as follow:（1）A novel FeS-NiS nanosheet array on Ti mesh（FeS-NiS/TM）was synthesized by two-step hydrothermal methods as a high performance electrocatalysis for water splitting.FeS-NiS/TM processed good OER electrocatalysis property,and only required overpotential of260 m V to drive a current density of 10 m A cm^-2 in 1.0 M KOH,which is less than those required for FeS/TM and NiS/TM.Furthermore,this electrocatalyst displays good durability,with maintenance of its activity for at least 25 h.And at overpotential of 500 m V,this catalyst electrode achieves a high turnover frequency of 0.521 mol O₂ s^-1.The improved catalytic performance can be attributed to the synergistic effect of electron interaction and the exposure of more active sites in the nanoarray materials.（2）Using carbon cloth as substrate,Fe-CoS₂ nanosheet array（Fe-CoS₂/CC）was synthesized by two-step hydrothermal method,Fe-CoS₂/CC has excellent catalytic activity for oxygen evolution reaction under 1.0 M KOH.When the current density is 10 m A cm^-2,the overpotential is only 302 m V,less than CoS₂/CC.In addition,this catalyst also has good stability,which maintenance of its activity for at least 20 h.The improvement of catalytic activity can be attributed to the atomic coupling between Fe and CoS₂ and the increase of surface roughness after doping Fe.（3）The Co-MOF nanoarray growth on Ti mesh（Co-MOF/TM）was synthesized by one-step hydrothermal method.The synthetic Co-MOF/TM can be used to detect H₂O₂ sensitively and quickly,it can determinate H₂O₂ in the linear range of 1×10^-3-13 m M.The limit of detection（LOD）as low as 0.25μM and can be further used to detect H₂O₂ released by living cells.The good response of CO-MOF/TM to H₂O₂ is mainly attributed to the large specific surface area and rapid electron transfer rate,which has great application potential in the field of electrochemical sensing.（4）The Ni-MOF nanoarray based on Ti mesh（Ni-MOF/TM）was synthesized through hydrothermal method.The reduction of H₂O₂ by Ni-MOF/TM showed a good electrocatalytic activity and showed a good linear relationship with the current response in the range of H₂O₂concentration of 0.8 m-6.6 m M.In this experiment,Ni-MOF/TM demonstrated a low LOD and good selective.Ni-MOF/TM has good electrical conductivity and is favorable for electron transfer to reduce H₂O₂,which can be further used for the detection of H₂O₂ in actual samples serum,with satisfactory results.