Construction Of Electrochemical Sensors Based On Black Phosphorus And Their Application In The Detection Of Hydrogen Peroxide

Hydrogen peroxide is an essential molecule that exists in biological systems and also plays an important role in environmental monitoring,food manufacturing,clinical medicine,and other fields.The fast and accurate detection of H₂O₂is significant and necessary.Electrochemical methods are considered to be the most promising technique due to the advantages such as fast speed,simplicity,and high sensitivity.Electrode materials are crucial in electrochemical detection.Black phosphorus（BP）,a two-dimensional material that has received much attention in recent years,is considered as a very promising material for biosensing electrodes with excellent carrier mobility efficiency,high specific surface area,and good biocompatibility.However,compared to the booming development of various kinds of BP-based electronics and optoelectronics devices,the exploration of BP-based biosensors is still in its cradle,especially in the enzyme-free biosensing field,which may be caused by the susceptibility of black phosphorus toward the water and air.Therefore,improving the electrochemical stability of black phosphorus is the key to BP-based biosensors.In this paper,the electrochemical stability of BP was enhanced by doping metals after obtaining BP nanosheets by liquid-phase exfoliation,and then the electrochemical properties of the BP-based composites were investigated by metal and transition metal oxide composites to explore the applications of the composites in the field of H₂O₂detection.The main research is as follows:1.An enzyme-free hydrogen peroxide electrochemical sensor based on a black phosphorus-gold-silver（BP@Au-Ag）nanocomposite system was constructed.The BP@Au-Ag nanocomposite was synthesized by the ultrasonic method under low-temperature conditions,and cyclic voltammetry showed that doping metals could effectively improve the electrochemical cycling stability of the BP-based material and exhibit high electrocatalytic performance at a gold/silver ratio of 2:1.The BP@Au-Ag nanocomposite system exhibited excellent anti-interference ability and good electrochemical cycling stability,showing a good linear relationship between catalytic current and hydrogen peroxide concentration in the range of 0.005-2.36 m M,with a low detection limit of 1.098μM.2.The enzyme-free hydrogen peroxide electrochemical sensor was constructed based on black phosphorus nanosheets loaded with gold-copper nanoparticles（BP@Au-Cu）.Firstly,tetrachloroalloy and copper chloride solution were added to the black phosphorus solution,then polyethyleneimine solution was added,and finally sodium borohydride solution was added under nitrogen atmosphere,and the BP@Au-Cu nanocomplex was obtained by stirring.The effect of the variation of the copper content on the detection of hydrogen peroxide was explored.It was found that the response current increased with increasing copper content.Cyclic voltammetry showed better electrochemical performance at a copper chloride solution concentration of 240 m M.The amperometric determination of H₂O₂was achieved in the range of 0.001-1.623 m M and the detection limit was found to be 0.625μM for the sensor based on BP@Au-Cu nanocomplex.3.Enzyme-free electrochemical detection of hydrogen peroxide by preparing black phosphorus-gold-cobalt tetraoxide（BP@Au-Co₃O₄）nanocomplex electrode materials.Co₃O₄nanoparticles was synthesized by hydrothermal method.Compared to BP@Au,BP@Au-Co₃O₄has better electrocatalytic performance for hydrogen peroxide by cyclic voltammetry due to the abundance of valence states of Co₃O₄,which can easily lose and gain electrons.When the mass of Co₃O₄is 5 mg,it shows the maximum sensitivity.The results of chronoamperometry showed that the linear detection range of the sensor based on BP@Au-Co₃O₄nanocomplex was 5-412μM at low concentration and 412-2360μM at high concentration,with low detection limit of 0.521μM.