Application Of Carbon Nitride Nanomaterials For Electrochemical Sensors

Electrochemical sensor is a common detection device in the field of electrochemistry,and it has been widely studied and applied in industry,agriculture and environmental protection,owing to its high sensitivity,simple operation,facile miniaturization and low price.Electrode modified material is a main factor to improve the selectivity and sensitivity of electrochemical sensors.Therefore,the development of novel electrode materials is an important research direction in the field of electrochemical sensors.Carbon nitride nanomaterials are inorganic non-metallic catalysts with large surface area,high mechanical strength and stability,excellent catalytic performance and good biocompatibility.They are widely used in the fields of photocatalysis,biosensors,supercapacitors and fuel cells.The introduction of nitrogen atoms in carbon materials can form defects on the surface,and enhance the surface activity of carbon materials.Meanwhile,the doping of nitrogen atoms can also increase the active sites in carbon materials and improve the catalytic performance.On the other hand,carbon nitride?C₃N₄?possesses abundant uniform nitrogen coordinators and defects,which can be easily modified with various metal nanoparticles.C₃N₄decorated with metal nanoparticles can greatly improve the conductivity of C₃N₄,and expand the application of C₃N₄ in the electrochemical sensors.This paper aims to construct the electrochemical biosensors with C₃N₄ and nitrogen–doped carbon materials for the detection of thrombin and small biomolecules.1.Using graphite-like C₃N₄ and AgNO₃ as the precursor,NaBH₄ as reducing agent,silver-modified g-C₃N₄ nanohybrid?Ag-g-C₃N₄?is successfully synthesized via chemical reduction.A label-free electrochemical aptasensor for thrombin is constructed using Ag-g-C₃N₄ as the electrode substrate.Ag-g-C₃N₄ has a large surface,good biocompatibility and abundant binding sites,which can immobilize a large number of aptamers through strong Ag–N bonds and improve the analytical performance of aptasensor.The proposed aptasensor shows a wide linear range and low detection limit.2.Polydopamine nanospheres are synthesized by self-polymerization of dopamine in the mixture of doubly distilled water,ethanol and ammonia.Nitrogen doped carbon nanospheres?N–CS?are prepared by one-step calcination with polydopamine nanospheres as the carbon source and melamine as the nitrogen source.N–CS is utilized as an electrode modified material to construct an electrochemical sensor for simultaneous detection of ascorbic acid,dopamine and uric acid.The nitrogen atoms in N–CS can interact with three molecular via hydrogen bond,which can active the hydroxyl and amino group and promote the occurrence of catalytic reactions.The large surface area of N–CS is also conducive to the catalytic reaction.The designed electrochemical sensor exhibits good selectivity,reproducibility and stability for ascorbic acid,dopamine and uric acid simultaneously sensing.