The Preparation Of KCu₇S₄ Derived CuO-based Composite Nanomaterials And Study Of Their Electrochemical Performance

With the development of human society,the electrochemical biosensors and supercapacitors have great research significance for life science detection and the development of clean energy.The efficient electrode materials play a vital role in the filed of electrochemical sensing and energy storage.This article mainly discusses the application of the KCu₇S₄-based materials in the field of glucose sensor and supercapacitor,and further investigate the influence of the composition and microstructure of electrode materials to the electrochemical performance.The research contents and innovations of this article are as follows:（1）The 1D KCu₇S₄ nanowires were used as self-template to prepare the 3D D-CuO nanobundles by simple hydrothermal method with assistant calcination,and the special D-CuO nanobundles consist of abundant nanosheets.We further investigate the electrochemical application of KCu₇S₄ template and CuO products.The results show that the prepared 3D D-CuO nanobundles modified GCE exhibit excellent electrooxidative performance due to the advantages in terms of solid-liquid interface binding,morphology and the specific surface area.The D-CuO based glucose sensor has high sensitivity,fast response time,good repeatability and reproducibility,excellent anti-interference,long-term stability for glucose detection with simple storage condition.And it also has great application potential in the clinical diagnosis of diabetes.（2）In order to further improve the prepared CuO system,the KCu₇S₄/NiCo precursor composite was first prepared by chemical co-precipitation method,then the internal KCu₇S₄ nanowires were further oxidized by hydrothermal method.Combine the last calcination,the CuO@NiCo₂O₄core-shell structure was prepared successfully.The final product（CuO@NiCo₂O₄ core-shell structure）was apply in supercapacitor and glucose sensor,and the range of application was broadened.In terms of energy storage,the composite structure has a higher specific capacitance(198.2 F g^-1),better cycle stability（retention rate of 82.5%after 1000 cycles）,and good rate performance than pristine CuO.In terms of glucose sensing,the composite has high sensitivity(504.8μA cm^-2 m M^-1),wide detection range（1μM-4.664 m M）,ultra-low detection limit（233 n M）,short response time（<2 s）,excellent anti-interference,repeatability and reproducibility.The results show that the prepared CuO@NiCo₂O₄ composite is a multifunctional electroactive material.（3）KCu₇S₄,as the electrode material for supercapacitor,there is still a lot of room for improvement.The application of NiCo-LDHs as electrode materials for supercapacitor has evoked widespread attention.However,the pristine NiCo-LDHs always suffer from low conductivity and instability to limit the electrochemical performance in supercapacitor.Here we rationally engineered a novel KCu₇S₄@NiCo-LDHs core-shell structure with good capacitive performance using a simple one-step coprecipitation method for electrode material of supercapacitor.The KCu₇S₄ nanowires act as a dependable“skeleton”for supporting the NiCo-LDH nanosheets,preventing the aggregation of NiCo-LDHs and improving the conductivity.By controlling the reaction time and the ratio of Ni/Co in the precursor solution,the results of electrochemical tasting show that the optimal composite is obtained with Ni/Co=2/1 and reaction time of 8 h,the final KCu₇S₄@Ni₂Co₁-LDHs composite possesses a high specific capacitance of 1104.5 F g^-1(122.7 m Ah g^-1)at 2 A g^-1,good rate capability of 65.9%when the current density reach up to 10 A g^-1,and long-term stability（83.5%after 1000 cycles）.This article focuses on the derivation and composition of KCu₇S₄ nanowires,and further investigate the electrochemical performance in glucose sensor and supercapacitors.The preparation of derived CuO nanobundles provide new ideas for biosensing materials.The CuO@NiCo₂O₄composite material has achieved multi-functionality in electrochemical applications.The KCu₇S₄@Ni₂Co₁-LDHs core-shell structure exhibits excellent electrochemical performance as the energy storage material.