Synthesis Of Cerium Oxide Modified Nickel-based Catalysts And Study Of Electrolytic Water Performance

As fossil energy reserves are decreasing and environmental problems are becoming more and more serious,there is an urgent need to develop a clean and sustainable energy source to replace traditional fossil energy sources.Hydrogen energy has good combustibility,high heating value,and non-toxic,non-polluting characteristics,which can become the best energy carrier to solve our energy security and environmental problems.Hydrogen production from electrolytic water is one of the most pure ways to produce hydrogen,but the slow kinetics of the anode limits the development of electrolytic water hydrogen production technology,requiring additional electrical energy,consuming more energy and causing waste.Therefore,the use of suitable catalysts in the electrolytic water hydrogen production process can reduce the overpotential,accelerate the electron transfer rate and further improve the energy conversion efficiency.Currently,precious metal catalysts,such as Pt、Ru O₂、Ir O₂,etc.,are hindered from large-scale commercial application due to their small reserves and high prices.Therefore,the development of a cheap,stable and abundant non-precious metal catalyst instead of precious metals is of great significance for the application and diffusion of electrocatalytic hydrogen production technology.In recent years,transition metal nickel-based and its compounds have shown excellent electrochemical properties,which can effectively improve the efficiency of hydrogen production from electrolytic water.The objective of this thesis is to prepare highly efficient and stable catalysts for the electrolysis of aquatic hydrogen,focusing on the morphology,composition and electrocatalytic performance of cerium oxide modified nickel-based catalysts.The details of the study are as follows:（1）A simple one-step hydrothermal method was used to successfully prepare CeO₂nanoparticles,carbon spheres,and highly dispersed Ni Fe-LDH CeO₂-N@CB/Ni Fe LDHs electrocatalyst.The electrochemical test results show that,under the condition of 1.0 M KOH,the CeO₂-N@CB/Ni Fe LDHs catalyst exhibits a rapid reaction kinetics rate with a current density of 20 m A·cm^-2and an overpotential of 203 m V and a Tafel slope of 16 m V·dec^-1.And the Cdl value can reach 6.2 m F·cm^-2,with a fast electron transfer rate and abundant active site.The lower charge transfer resistance Rct has the fastest Faraday process in the oxygen evolution reaction（OER）process.（2）The CeO₂-Ni₂P/NF electrode is obtained by high temperature hydrothermal addition of CeO₂and then low temperature phosphatization treatment,which improves the microstructure of the electrode through the synergistic effect between Ni-Ce,increases the loading of Ni OOH active substance,enriches oxygen vacancy defects,and improves electrochemical performance.The electrochemical test results showed that the oxidation current density of CeO₂-Ni₂P/NF electrode was 773.6 m A·cm^-2at 0.6 V in 3.0 M KOH+0.6 M Urea electrolyte,and the starting oxidation potential was only 0.17 V,which was71.2 m A·cm^-2higher than that of Ni₂P/NF electrode.Cerium oxide modified nickel-based phosphide is a novel and very promising OER electrocatalyst that has a catalytic effect on improving the efficiency of electrolytic hydrogen production.