Preparation And Application Of Hydrogen Peroxide Sensor Based On Doped Graphene

Hydrogen peroxide（H₂O₂）is widely used as an oxidizing agent in food,clinical diagnostics and biotechnology,and plays an important role as a disinfectant especially in today’s widespread spread of Novel coronavirus.However,excessive concentration of H₂O₂ can also cause damage to human skin and eyes,therefore,the efficient quantification of H₂O₂ is an important research direction.In recent years,several technological platforms have been developed for measuring H₂O₂,among which electrochemical sensing platforms have received great attention due to their high efficiency,simplicity and low cost.It mainly includes non-enzymatic and enzyme-based electrochemical sensors,however,the enzyme itself is limited in its function,which gives a great opportunity for the development of non-enzymatic sensors.In recent years,Graphene（Gr）and noble metal nanoparticle composites have attracted much attention in the field of H₂O₂ electrochemical sensing due to their efficient electrocatalytic properties.Based on this,we report a one-step synthesis of Ag⁺-doped Graphene precursor solution,direct modification of screen-printed electrode（SPE）,and laser etching technique to obtain Ag/rGO electrode as a fast and sensitive electrochemical sensor for the detection of H₂O₂.First,a chronoamperometry（CA）test was performed on H₂O₂ using a conventional platinum sheet as a counter electrode.The linear ranges of 1-110μM and 110-800μM were obtained from the test results and linear regression equations,with sensitivities of 118.7 and 96.3μAmM^-1cm^-2,respectively,and low limits of detection（LOD）of 0.24μM and 0.31μM,respectively（S/N=3）.At the same time,the electrochemical sensor shows excellent anti-interference ability,reproducibility and stability.Based on this,we also achieved good results in CA testing of H₂O₂ using screen-printed carbon electrode（SPCE）,which laid the foundation for portable detection.We synthesized cobalt oxide and graphene nanosolutions by hydrothermal method,compounded with the above experimentally synthesized Ag⁺precursor solution,and obtained a highly sensitive Ag/CoO/rGO/SPCE sensor under laser etching method.The chemical element composition and crystal structure of the composite were analyzed by XPS and XRD,and it was found that Ag nanoparticle（Ag NPs）improved the electrocatalytic activity of CoO nanomaterials.Based on the electrochemical test results,the modified electrode exhibited a wide linear range of 0.1-150μM and 150-600μM,low detection limits of 0.075μM and 0.057μM（S/N=3）,and high sensitivities of 391.8and 514.1μAmM^-1cm^-2.The strong oxidation ability of the synthesized composites against H₂O₂ was demonstrated,which shows the prospect for the development of this field.