Three-dimensional Electrochemical Nitrite Sensing Graphene-based Nanomaterials Utilizing Inexpensive Iron Oxides As Catalytic Core

Nitrite,which widely exists in the environment,generally refers to sodium nitrite?NaNO₂?.Nitrite can be used in various industries and manufactures,and it also acted as preservatives in meat products.However,nitrite can react with amines to generate a toxic nitrocompound,especially that it can be transferred to carcinogenic nitrosamine under an acidic condition.As we all know,the harmful nitrosamine can result in gastric cancer and esophageal cancer.Besides,excessive intake of nitrite can induce methemoglobinemia.WHO declares that the content of nitrite in drinking water cannot exceed 3 mg/L due to its harmfulness.So it is essential and significant to determine nitrite sensitively.Electochemical detection is a cheap,simple,immediate,sensitive and accurate method.The electrochemical performance strongly depends on the sensing nanomaterials onto the surface of electrodes.Here,in order to obtain ultrasensitive detection towards nitrite,two nanomaterials named as Fe_1.833?OH?_0.5O_2.5/NG@PDDA and Fe₂O₃/H-C₃N₄/rGO have been designed and fabricated sussessfully.The novel nanostructure and corresponding electrochemical properties were investigated in detail respectively.The results show that the coupling of Fe_1.833?OH?_0.5O_2.5 and PDDA enhances the electrocatalytic response of Fe_1.833?OH?_0.5O_2.5/NG@PDDA modified electrode to NaNO₂ significantly.And the elecetrochemical sensor exhibits a wide linear range of 0.1?347 ?mol/L and 347?1275?mol/L,a low limit of detection 0.027 ?mol/L.Besides,Fe₂O₃/H,C₃N₄/rGO nanostructure was constructed and.the results show that acidified carbon nitride?H-C₃N₄?was adsorbed uniformly onto the surface of reduced graphene?rGO?.The existence of large number of defect sites of H-C₃N₄ is beneficial to the growth of Fe₂O₃ nanoparticles,which would promote the improvement of electrochemical performance.The linear range was 25 nmol/L?3000 ?mol/L,and the limit of detection was 18.43 nmol/L.Furthermore,the two types of electrodes were tested in real tap water,which exhibits a good effect and high stability.Thus,the two fabricated nanomaterials have the potential for practical application.