Preparation Of Phosphates And Oxides Of Tin,Cobalt And Nickel And Their Application In Small Molecules Detection

It is very necessary to establish sensitive,simple,and rapid detection technology and methods for small molecules.Enzyme-based electrochemical sensors have limited their practical application due to high cost and instability.Therefore,non-enzymatic electrochemical sensors have attracted more and more attention.Studies have shown that electrochemical small molecule sensors based on non-noble metal oxides and phosphides have been favored by many researchers,but due to the influence of nanomaterial morphology and sensor interface construction methods,their sensitivity and detection limits have yet to be further improve.In addition,the use of conductive adhesive will bury some active sites and reduce its catalytic activity.In order to solve these problems,based on the unique structure and excellent electrochemical properties of the simplest oxide and phosphide nanomaterials of non-noble metals,SnO₂/CC,CoP/TM and NiO/CC nanoelectrode materials with high conductivity and large specific surface area were synthesized on carbon cloth（CC）and titanium mesh（TM）substrates by simple and efficient one-step hydrothermal method,low-temperature phosphating method and one-step flame method,respectively.More active sites of the catalyst can be exposed by using the porous characteristics of self-supporting substrate materials,which can effectively improve the electrocatalytic activity of simple non noble metal nanomaterials.The electrochemical sensor constructed with this working electrode has excellent performance in the detection of some small molecules,which provides potential for practical detection.This thesis mainly includes the following three parts:1.Study on non-enzymatic H₂O₂ sensing properties based on SnO₂ nanorods（SnO₂/CC）SnO₂ nanorods（SnO₂/CC）were grown in situ on a carbon cloth（CC）substrate by a one-step hydrothermal method.As an efficient enzyme-free H₂O₂ sensor,it has an excellent sensitivity of 24840μA m M^-1 cm^-2,a linear range of 0.10μM-1.0 m M,a limit of detection（LOD）of 9.94 n M at S/N=3,and a response time less than 3 s.At the same time,the sensor also has good anti-interference,certain reproducibility and stability.2.Preparation of CoP nanowires（CoP/TM）by low-temperature phosphating and study on NO₂^-sensing propertiesThe titanium mesh（TM）was used as the substrate,and the CoP cobalt phosphide nanowire material（CoP/TM）was obtained by the method of hydrothermal and phosphating.The electrochemical test results show that the CoP/TM electrode has a highly efficient catalytic performance on the reduction of NO₂^-.The linear detection range is 1.0μM-4.5 m M,the detection limit is 18 n M（S/N=3）,and the sensitivity is 1778μA m M^-1 cm^-2.The sensor has good stability and strong anti-interference ability,and can be used for the detection of NO₂^-in actual water samples.3.Preparation of NiO nanoparticles（NiO/CC）by flame method and study on glucose and formaldehyde sensing propertiesThe ultra-small NiO nanoparticles（NiO/CC）are synthesized in one step on CC by using a low-cost and simple flame method.Electrochemical test results show that NiO/CC has a good electrochemical response to both glucose and formaldehyde under the best conditions:the linear detection range of glucose is 5.0μM-2.0 m M,the detection limit（S/N=3）is 7.45 n M,and the sensitivity is 4025μA m M^-1 cm^-2;the linear detection range of formaldehyde is 1.0μM-3.0 m M,the detection limit（S/N=3）is 6.8 n M,and the sensitivity is 5752μA m M^-1 cm^-2.The NiO/CC sensor has good selectivity and can be used for the measurement of glucose in actual serum samples.