Preparation Of Transition Metal(cu Ni Co Fe)Modified Honeycomb Carbon And Its Electro Analytical Properties

In this paper,the 3D-honeycomb carbon materials modified by Cu,Ni,Co,and Fe for the electrochemical analysis of typical organic and inorganic small molecules were designed and developed.The electrochemical oxidation analysis of uric acid,dopamine,ascorbic acid,hydrazine hydrate,and electrochemical reduction analysis m-nitrobenzene and nitrate were researched.The changes in the content of uric acid,dopamine and ascorbic acid in urine can reflect the health of the human body to a certain extent.Hydrazine hydrate,m-nitrobenzene and nitrate are important industrial raw materials and may also have an adverse impact on environmental safety.The research and development of a typical organic-inorganic small molecule mentioned above is of great practical significance in developing a portable,simple and easy-to-operate and high-sensitivity detection method.Compared with traditional mass spectrometry,spectrophotometry,liquid chromatography,etc.,the electrochemical analysis method is simple,fast and cheap,Especially suitable for the detection and monitoring of specific substances in specific systems.The high sensitivity and low background current of the electrochemical analysis method depend on the large specific surface area of the electrode material and the choice of catalyst type.This article focuses on the design of electrode materials with high sensitivity,high selectivity,and a wide linear range,and further explores to optimize the electrochemical test condition.In this paper,the NaCl template method is used to prepare porous carbon with a similar honeycomb structure and a large specific surface area(hereinafter referred to as honeycomb carbon).The cheap transition electrons with empty d electron orbitals can effectively catalyze more reactions.Fe and Co modified honeycomb carbon to prepare catalysts for electroanalysis.The prepared honeycomb carbon has a typical three-dimensional porous structure with thin carbon walls and interpenetrating channels.CuNi alloys with a size of about 13 nm are respectively loaded on them to detect uric acid,ascorbic acid and dopamine,and Cu particles and cobalt hydroxide nanoparticles was used to detect hydrazine hydrate,the Prussian blue analogue-supported catalyst was used to detect m-dinitrobenzene,and Cu particles with a size of about 60 nm were used for electrochemical reduction analysis to detect nitrate.This article is divided into two parts:electrochemical oxidation and electrochemical reduction analysis of nitrogen-containing small molecules.In the first part of this article,glucose and dicyandiamide are used as carbon sources,and the metal salt is directly added to freeze-drying.One-step calcination prepared CuNi-MPC(CuNi-loaded honeycomb carbon),which was used to electrochemically oxidize uric acid(UA),dopamine(DA),and ascorbic acid(AA).Calcination of the water-washed catalyst at 900? can detect three substances at the same time without interference and have the highest sensitivity,which are(AA)0.17 uA/uM/cm2,(DA)5.31 uA/uM/cm2,(UA)1.71 uA/uM/cm2.The normal range of human uric acid is 149-417?mol/L for men,89-357 ?mol/L for women,the dopamine content is 0.93-2.59 ?mol/L,and the ascorbic acid content is 0.285-0.741 mmol/L.The content of three substances in human body fluid can meet the test requirements.In the first part,in addition to the analysis and testing of small organic molecules,Cu-MPC was prepared by dipping and electrodeposited Co(OH)2.CuCo-MPC was also prepared.It also has good electrocatalytic oxidation of nitrogen-containing inorganic substances such as hydrazine hydrate.Compared with the test results in the general literature,the catalyst prepared in this paper can be tested at a negative potential(-0.1 V vs.SCE)in 0.1 M PBS(phosphate buffer)solution,and the sensitivity is 45 uA/uM/cm2 when the concentration of hydrazine hydrate below 40 mM,detection limit is 0.75 uM.The result is attributed to the large specific surface area of honeycomb carbon providing more adsorption sites,and the synergistic effect of transition metals Cu and Co providing excellent catalytic performance.In the second part of this paper,the Prussian blue analogue(CoFe-PBAs)was loaded on honeycomb carbon by impregnation method for the electrochemical reduction analysis of m-dinitrobenzene.Due to the strong electrocatalytic activity of the Prussian blue analogue and the strong adsorption properties of the honeycomb carbon material itself,the detection of m-nitrobenzene with this catalyst has a very low background current,the detection potential is corrected and the sensitivity is very high,reproducibility,Parallelism and anti-interference are also good.When Prussian blue analog content is 65%,the electrode has the best electrochemical performance,and can be detected without interference in the presence of other ions or organic substances 20 times higher than its concentration.The sensitivity is as high as 1085.7 uA/ppm/cm2 at a low background current,and the linear range is 5 ppb-2000 ppb;It can also detect m-dinitrobenzene at a very low concentration of 5 ppb.The content of m-nitrobenzene in drinking water sources in China should not exceed 0.5 mg/L,so this catalyst can effectively analyze and test m-nitrobenzene between drinking water sources.The copper-modified honeycomb carbon Cu-MPC prepared by the impregnation method has excellent electrocatalytic reduction performance for nitrogen-containing inorganic substances represented by nitrate.Cu-MPC can reduce nitrate ions at a potential closer to 0 V(vs.SCE)and has good stability.The World Health Organization(WHO)stipulates that the content of nitrate in drinking water sources should be less than 20 mg/L.Studies have shown that Cu-MPC can be applied to the rapid electrochemical reduction analysis of nitrate in drinking water sources.In summary,the transition metal(Cu Ni Co Fe)modified honeycomb carbon catalyst prepared in this paper can be used for rapid and effective electrochemical analysis and testing of the above-mentioned environmentally harmful substances and some nitrogen-containing organic and inorganic small molecules contained in body fluids,which is real-time Monitoring such substances provides a convenient and effective test method.