The Study Of Oxygen Evolution Reaction Of Carbon/Layer Double Hydroxide Composites

Energy is relatively scarce in the 21 st century,Hydrogen energy because of its clean pollution-free and renewable characteristics,It is considered the most promising new energy alternative to fossil fuels.In this paper,bimetallic hydroxides composed of metallic elements such as nickel,cobalt and iron,which have high catalytic activity,good stability and low cost,are studied in alkaline electrolyzed water.In order to prevent agglomeration inside the active materials,to improve its microstructure and electron mobility,thereby enhancing the electrochemical catalytic activity of the material by combining with grapheme and carbon spheres.The specific research contents are as follows:(1)The oxidized graphite was prepared by the improved Hummers method.The graphite oxide was oxidized in an inert gas atmosphere at 500 ? for 2 hours to obtain reductive graphene.A 0.5M glucose solution was incubated at 190°C for 1 hour by a hydrothermal method to obtain the carbon spheres.The oxygen-containing functional groups on the surface of the carbon spheres and the reduction of the graphene oxide will provide active sites for the in situ growth of bimetallic hydroxides.(2)The NiFe-LDH was prepared by the hydrothermal method and recombined with reductive graphene and carbon spheres in different proportions.The results show that the addition of reductive graphene and carbon sphere can prevent the NiFe-LDH from agglomeration and improve its catalytic activity.When the NiFe-LDH/RGO=1/1,the initial oxygen evolution potentials in 0.1M and 1M KOH solution were 1.51 V,1.46 V,and the limiting current density is maximum at the electrode potential of 1.75 V,were 22.3mA/cm~2 and 123.1 mA/cm~2 respectively.At the current density of 5 mA/cm~2,10 mA/cm~2,20 mA/cm~2 for a long time under the tests show the good stability.(3)The CoNi-LDH was prepared by a sol-gel method,and a certain amount of reductive graphene and carbon sphere were doped respectively.The results show that the two carbon materials combine with CoNi-LDH to form a relatively stable structure,which improves the oxygen evolution and the stability of the materials.When the NiFe-LDH/RGO=20/1,the initial oxygen evolution potentials in 0.1M KOH solution were 1.52 V,and the limiting current density is maximum at the electrode potential of 1.8V was 26.1 mA/cm~2.the initial oxygen evolution potentials in 1M KOH solution were 1.51 V,the limiting current density is maximum at the electrode potential of 1.75 V was 102.6 mA/cm~2.Long-term testing at a current density of 5 mA/cm~2 showed good stability.