Non-enzyme Glucose Sensing Of Copper-based Nanomaterials Based On HKUST-1

The rapid,simple,convenient and in situ detection technology of glucose concentration in the solution has been widely used in many fields,such as health care,food processing,chemical preparation,bioengineering and so on.Electrochemical glucose sensor has the characteristics of high selectivity,fast response and simple operation,making it the main tool for glucose detection.Enzymes are used in the current electrochemical glucose sensors.However,the instability of enzyme restricts its application.Therefore,the research of non-enzyme electrochemical glucose sensos has attracted wide attention.Transition metal nanomaterials become the main research object with low price,good glucose electrocatalytic performance and stability.Metal organic frameworks?MOFs?is a composite functional material formed by coordination between metal centers and organic ligands.As a promising template material,MOFs has porous structure and large specific surface area.In this paper,a series of copper?carbon?based nanomaterials was prepared by pyrolysis of HKUST-1.The performance of the material in nonenzymatic glucose sensors has been studied.Specific research results are shown as follows:Cubic HKUST-1 was synthesized by solvothermal method.The porous Cu@C cube was prepared by pyrolysis of HKUST-1 under N₂.It is found that the Cu@C pyrolyzed at 400 ^oC?recorded as Cu@C-400?own the largest pore diameter?9.28 nm?,which is benefit to the transfer of glucose and solvent molecules.The elemental analysis and TG results indicate that the carbon content of Cu@C-400 is 21.93 wt%.In addition,Cu@C-400 shows the lowest charge transfer resistance R_ct?0.94 K??in the charge transfer process,indicating that it had the largest amount of catalytic active sites.As a result,Cu@C-400 shows good sensing performance towards glucose detection with wide liner range of 0.005-3.3 mM and sensitivity of 383.9?A mM^-1.Copper based non-enzyme glucose sensor generally showed a narrow detection range,while nickel based sensor had wide detection range.Therefore,we try to improve the detection range of Cu@C composites with the synergy effect between Cu and Ni.Ni²⁺ion was introduced into HKUST-1 by impregnation.The CuNi@C was obtained by pyrolysis of the precursor under N₂.When the ratio of copper and nickel is 1:1?recorded as Cu₁Ni₁@C?,the non-enzymatic glucose sensor shows a wide linger range of 0.005-0.8 mM and 1.8-10.3 mM,the sensitivity is 70.52?A mM^-11 and 20.68?A mM^-1.Compared to Cu@C-400,Cu₁Ni₁@C shows much wide liner range.However the sensitivity of Cu₁Ni₁@C is reduced.Since the pore size?7.98?is smaller,and charge transfer resistance(R_ct=9.76 K?)is larger than Cu@C-400,we conclude that Cu₁Ni₁@C has deteriorating transfer capacity of glucose molecules and charge transfer rate,leading to the decreased sensitivity.As Cu₁Ni₁@C owns a carbon content of 31.15wt%,which is larger than Cu@C-400?21.93 wt%?,we propose that more carbon will be filled into the cube to reduce the pore size and cover the metal catalytically active sites.We prepared porous copper@carbon agglomerate?PCCA?and porous copper/nickel@carbon agglomerate?PCNCA?by thermal treatment of HKUST-1 and Ni²⁺/HKUST-1 under N₂-H₂ atmosphere.The carbon contents of PCCA and PCNCA are3.04 wt%and 11.03 wt%,and the pore size are 13.02 nm and 8.75 nm.The charge transfer resistance(R_ct)are 0.69 K?and 1.26 K?.Compare to Cu@C-400 and Cu₁Ni₁@C,the lower carbon contents of PCCA and PCNCA cause larger pore size and lower charge transfer resistance.As a result,PCCA and PCNCA get higher sensitivity of614.3?A mM^-1and 143.6?A mM^-11 respectively,better than Cu@C-400 and Cu₁Ni₁@C.