Controllable Preparation Chararcterization And Electrocatalytic Oxygen Evoution Of Cobalt-Nickel Composite Metal Oxide/Nano/Microelectrocatalytic Materials

The world's economic and social development have facing two major problem which are Energy shortages and environmental crises.it is urgent that we improve the utilization rate of fossil resources and seek new ways to use energy.Hydrogen is widely concerned and studied by many countries because of its high energy density(142 mJ Kg-1)and its environmental friendly during use and release.Hydrogen production of electrolyzed water is an effective way to convert electrical energy into chemical energy and is also an important direction for future development.The oxygen evolution reaction(OER)is highly dependent on the pH of the reaction system,which limits the increase in hydrogen production efficiency of electrolyzed water.In recent years,the research work in the field of electrocatalysis is mainly devoted to the development of non-precious metal electrocatalytic materials.metal electrocatalytic materials are abundant resource reserves,low cost,good electrical conductivity and electronic structural characteristics.besides,a large number of transition metal oxides and hydroxides are designed and prepared with controlled composition and structure.Materials,nitrides,borides,phosphides,composite metal oxides,etc..But problems such as poor acid and alkali resistance,poor stability and easy catalyst loss still stay exist.so how to design and develop high activity,high stability,strong acid and alkali resistance,in a wide pH range The new high-efficiency electrocatalytic materials with high OER performance are the research hotspots and difficulties in improving the yield of electrolyzed water,especially the chemical conversion and storage of energy.Based on the previous reports,Co and Ni metals with excellent electrocatalytic properties were selected.Foamed nickel was used as the conductive framework.In situ deposition was used to prepare the morphology and controllable acid and alkali resistance on the surface of the foamed nickel skeleton structure.The high-electrocatalytic activity of nickel-cobalt composite metal oxide nanomaterials,through the composition,structure,morphology,surface modification and other methods,obtained P-NiCo2O4/NF electrocatalytic materials modified with phosphorus with excellent OER performance and CeO2-NiCo2O4/NF electrocatalysts with CeO2 modified in defect-rich sites were used to investigate the OER performance and total water-splitting properties of a series of electrode materials in a wide pH range.The effects of electrocatalyst composition and structure on catalytic performance were investigated.The design and development of catalytic materials provide new ideas.1.Using nickel foam as the base,cobalt nitrate and nickel chloride as the metal source,cetyltrimethylammonium bromide as the surfactant,one-step hydrothermal method,and one-dimensional linearity on the surface of foamed nickel.The structure of cobalt-nickel hydroxide NiCo(OH)x/NF precursor,by the preparation conditions such as crystallization temperature,time,surfactant dosage and other conditions to achieve the shape and size of NiCo(OH)x nanowires.The control was followed by phosphating of sodium hypophosphite to obtain a phosphorus-modified one-dimensional P-NiCo2O4 nanowire.The effects of composition,morphology and phosphating conditions on the properties of P-NiCo2O4/NF electrode materials were investigated systematically.The results show that the length of NiCo(OH)x is controllable within xx?xx?m,and the aspect ratio is about 0.5-2?m,the obtained nanowires were staggered on the surface of the foamed nickel skeleton structure and constructed into NiCo2O4/NF electrode materials with three-dimensional nano/microstructure.Phosphating treatment had little effect on the morphology of NiCo2O4/NF.The unique nano-structure makes the obtained P-NiCo2O4/NF electrode material have a high electrochemical active area(CdI=23.31 mF cm'2),and the electronic interaction between the phosphorus component and the nickel-cobalt composite metal oxide significantly reduces the obtained NiCo2O4/NF.The OER overpotential of the electrode material,in the lM KOH electrolyte,the OER overpotential is 301 mV when the current density is 50 mA cm-2,and the Tafel slope is 46 mV.dec'1,compared with the results of the existing literature.The catalyst has high OER activity and stability.2.Nico(OH)x/NF nano/microstructure with urticue is constructed on the surface of foamed nickel by using foamed nickel as the base and sodium alginate as the surfactant.One-dimensional NiCo(OH)x nanowires are assembled.It is transformed into the corresponding skeletal nickel-cobalt composite metal oxide NiCo2O4 by calcination treatment,and then the CeO2 nanoshell with rich defect sites is modified on the surface of NiCo2O4 by electrodeposition to obtain CeO2-NiCo2O4/NF electrode material.And to investigate its reaction performance in OER and total solution water.The results show that the calcination and electrodeposition treatments do not destroy the NiCo2O4 nano/microstructure of the ribbed structure.High catalytic properties of nickel-cobalt composite metal oxide itself,excellent conductivity and loose porous structure of one-dimensional CeO2-NiCo2O4 nanowires and ribbed assembly units,and contact between CeO2 and active oxides in the catalyst And activation makes the CeO2-NiCo2O4/NF electrode material exhibit excellent catalytic performance in the OER reaction.In the 1 M KOH electrolyte environment,when the current density is 10 mA·cm-2,the OER has The potential is 217 mV;in the acidic electrolyte environment,the OER overpotential is 334 mV,which is significantly lower than that reported in the literature,and the catalytic material exhibits a high total water-splitting performance.