Studyonpreparation Of Catalysts For Oxygen Evolution Reaction And Hydrogen Peroxideproduction By Oxygen Cathode Reduction

Hydrogen peroxide is an important industrial raw material and chemical reagent in the industry.It plays an irreplaceable role in many fields such as medical,food and chemistry.The methods of industrial hydrogen peroxide production are mainly anthraquinone,electrolysis and isopropanol.At present,anthraquinone is the main method of production.But hydrogen peroxide is not suitable for storage and transportation,so the application cost of hydrogen peroxide is increased.Therefore,the oxygen cathodic reduction method is used in the experiment to make hydrogen peroxide in situ,which solves the disadvantages that are not suitable for storage and transportation,and is directly applied to sewage treatment.The oxygen evolution reaction?OER?and oxygen reduction reaction?ORR?of the anode and cathode of the in situ hydrogen peroxide were produced in situ,respectively.By preparing the efficient OER and ORR catalysts,the prepared catalysts were applied to the in situ hydrogen peroxide unit to improve the hydrogen peroxide yield.In this paper,the preparation of two kinds of nickel and iron transition metal nanocomposites was prepared by one step hydrothermal synthesis method.The effects of two kinds of metal ratio,calcining temperature and atmosphere on the morphology,structure and particle size of the catalyst were investigated.X ray diffraction?XRD?,transmission electron microscopy?TEM?and X ray photoelectron spectroscopy?XPS?were used to characterize the catalyst.It was found that the catalyst had better crystallization properties when the Ni:Fe was 1:1 and the calcined temperature was 600?.It is found that the nickel iron oxide catalyst has better catalytic activity for OER reaction,the overpotential is 291 mV and the Tafel slope is 86 mV.dec^-1 when the nickel iron ratio is 1:1 and is calcined under the protection of nitrogen atmosphere at 600?.The NiFe alloy catalyst has better OER catalytic activity than the nickel iron oxide,the overpotential is 258 mV,the Tafel slope is 68 mV dec^-1,and the30000 s cycle catalyst is still more stable.Through the preparation of ORR catalyst,the catalyst is biased towards the two electron mechanism in the reaction process.The cobalt,nickel and nickel iron catalysts were tested by the electrochemical workstation.The number of electron transfer numbers of the pure nickel phase catalyst was n=2.2,while the nickel iron alloy catalyst n=3.6 was obtained through the K-L equation.So the pure nickel phase catalyst was more inclined to two electron pathway during the reaction process.The prepared catalyst was applied to the in-situ hydrogen peroxide unit on the carbon cloth.When the ORR catalyst was used as the cathode,the yield of hydrogen peroxide was three times higher than that of the graphite electrode under the same condition.The concentration of hydrogen peroxide reached 50.18 mg L^-1 at the reaction time of 240 min.When the OER catalyst is used in the anode,more hydrogen peroxide can be generated under the same conditions,which is consistent with the electrochemical test results.When the reaction time is 1000 min,the concentration of hydrogen peroxide reaches55 mg L^-1.The yield is close to using platinum electrode as anode material.