| Nonenzymatic electrochemical sensors are widely applied in clinical diagnosis,food safety,biochemical analysis and other numerous areas due to their low cost,easy preparation and operation,good stability and long service life.However,there are always a sequence of shortcomings in nonenzymatic electrochemical sensors such as narrow linear range,low sensitivity,high limit of detection and poor selectivity.As a result,it is urgent to synthesize highly-active catalysts to improve the performance of nonenzymatic electrochemical sensors.In this paper,different types of catalysts were fabricated and their sensing performance of nonenzymatic glucose sensor or nonenzymatic ascorbic acid sensor were then studied respectively.The key research details are as follows:(1)NiSeO4@NF was constructed by the direct growth of NiSeO4 nanowire arrays on 3D porous nickel foam through hydrothermal method and its catalytic performance for the oxidation of glucose in 1.0 M KOH electrolyte was systematically studied.Nanowire arrays can afford large specific area and make sufficient contact with electrolyte,which is beneficial to the exposure of active sites.Moreover,the strong interaction between 3D Ni skeleton and NiSeO4 nanowires endows the electrode good conductivity.Thereby,NiSeO4@NF exhibits remarkable activity to the oxidation of glucose with a high sensitivity(28720 ?A cm-2 mM-1)in 0.0005-2.5 mM linear range,a sensitivity(3700 ?A cm-2 mM-1)in 3-8 mM linear range and a low detection limit(0.26 ?M).In addition,it also shows good selectivity,reproducibility,repeatability and application prospect,which may be able to offer a new approach in the development of nonenzymatic glucose sensors.(2)Cu2O@ZIF-67 core-shell structure was formed by encapsulating pre-synthesized Cu2O into ZIF-67 via precipitation method and its catalytic performance for the oxidation of glucose in 1.0 M KOH electrolyte was detailedly examined.Attributed to the synergistic effects between Cu2O and ZIF-67,the content of Co3+increase obviously in Cu2O@ZIF-67,which is beneficial to the transformation of Co3+to Co4+,accordingly helpful to the oxidation of glucose.Thus,in contrast with Cu2O and ZIF-67,Cu2O@ZIF-67 demonstrates more excellent activity to the oxidation of glucose,which shows wider linear ranges,higher sensitivities and lower detection limit.Moreover,Cu2O@ZIF-67 also displays good selectivity,reproducibility and repeatability.More importantly,the determination outcomes of glucose concentration in human serum by Cu2O@ZIF-67 are almost in accordance with the results provided by hospital.On basis of the facts mentioned above,Cu2O@ZIF-67 is a hopeful candidate in practical application.(3)a-InOx@Ru were fabricated by anchoring Ru single atom on the derivatives of In-MOF via solvothermal and calcination methods and their catalytic performance for the oxidation of ascorbic acid in 1.0 M KOH electrolyte were investigated in detail.The electronic structure of composites can be modulated and the charge transfer can be accelerated by the introduction of single-atom Ru into amorphous InOx,which is beneficial to improve the activity and selectivity to ascorbic acid.Among them,a-InOx@Ru-100-300-1 displays a wide linear range of 0.01-56 mM,a high sensitivity of 144.34 ?A cm-2 mM-1 and a low detection limit of 0.3 ?M.Besides,it also shows good reproducibility and repeatability.Furthermore,a-InOx@Ru-100-300-1 is able to precisely detect the concentration of ascorbic acid in vitamin C tablets and lemons,which reveal that a-InOx@Ru-100-300-1 may supply a novel idea for nonenzymatic ascorbic acid sensors. |
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