Study On The Nitrite Electrochemical Sensing Performance Of N-Doping And Nitride

Nitrite,one of the participants in the broad nitrogen biogeochemical cycle,is ubiquitous within food,drinking water and human environment.Nitrite is usually used as food additives,but its potential toxicity can cause some health problems and even diseases.Excessive nitrogen content in the water will eventually lead to eutrophication and economic loss of aquaculture industry.Therefore,the rapid and simple detection of nitrite is of great significance.In addition,since the content of nitrite is very low and it often coexists with other ions in the human living environment,sensors with high sensitivity and good selectivity are necessary for detection.Focusing on nitrite ion detection,we discuss the effects of nitrite on the human environment and detection methods of nitrite.The three kinds of materials in this paper all have good electrocatalytic performance for nitrite and can be linear detected in a certain concentration range.The details are as follows:1.The precursor Ni hydroxide nanosheet array on the Ti mesh was calcined at low temperature to obtain N-NiO NA/TM,and the performance of N-NiO NA/TM electrocatalytic nitrite oxidation was explored.N-NiO NA/TM was characterized by XRD,SEM and XPS,and the effect of scanning rate on electrocatalytic activity was discussed.The experiment was carried out using N-NiO NA/TM as working electrode,platinum wire as counter electrode,saturated Ag/AgCl as reference electrode and 0.1 M PBS（pH 7.0）as electrolyte.It has been shown that the N-NiO NA/TM electrode has good selectivity,high electrochemical response and good stability.The concentration range of nitrite is 0.02～10 mM,the sensitivity is 389μA mM^-1 cm^-2,and the detection limit is as low as 5.83μM（S/N=3）.It can be used for the detection of real samples.2.The molybdenum disulfide nanosheet array grown on carbon cloth were transformed into MoN NA/CC by conformal nitriding.We report that the MoN NA/CC is efficient for the electroreduction of nitrite in 0.1 M PBS.The samples obtained were characterized by XRD,SEM,XPS and TEM.The electrochemical catalytic reduction of nitrite by MoN NA/CC was tested with a traditional three-electrode system,using cyclic voltammetry and chronoamperometry methods.As an electrochemical sensor toward nitrite detection,the MoN NA/CC offers a wide linear range from 1μM to 5 mM and a low detection limit of 3 Nm（S/N=3）,with a high sensitivity of 4319μA mM^-1 cm^-2 and long-term stability and reproducibility.3.Copper nitride was synthesized in one step by reducing copper acetate by calcining ammonia from urea as nitrogen source,and its performance as an electrochemical nitrite sensor was studied.The electrochemical nitrite sensor constructed with copper nitride electrode has a linear detection range of 0.02～5 mM,a sensitivity of106.4μA mM^-1 cm^-2,and a minimum detection limit of 7.5μM（S/N=3）.