Research On Construction And Performance Of High-Efficiency Electrocatalyst For Water Splitting

The extensive use of traditional fossil fuels not only causes the problem of energy depletion,but also leads to serious environmental pollution,therefore,seeking a kind of clean and renewable energy is the key to solve the problem.Hydrogen energy has attracted the wide attention of researchers because of its high energy density and safe by-product of water.Water electrolysis technology is an effective means of hydrogen production,and another product of electrolytic water is oxygen,which also has vitally important applications in smelting,national defense,medical treatment and so on.The efficiency of water electrolysis is determined by two half reactions of hydrogen evolution and oxygen evolution,and the efficient catalyst can greatly improve the efficiency of water electrolysis.At present,Pt/C and Ru O2 or Ir O2 are the most efficient catalyst for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),respectively.However,they are too expensive and rare to be widely used.Therefore,it is very important to develop efficient non-precious metal catalysts.Transition metals(Fe,Co,Ni,etc.)have been widely studied in the field of electrocatalysis because of their abundant reserves,low price and high catalytic activity.In this thesis,the electrocatalytic performance is optimized by tuning the morphology,composition and electron structure of materials.The research content of this thesis is divided into three parts: First,bimetal Ni Fe-MOF-74 with two-dimensional nanosheets structure were prepared by one-step hydrothermal method,and the morphology and electronic structure of the catalyst were optimized by the synergistic effect of bimetal;Second,cetyltrimethylammonium bromide(CTAB)was used as soft templates to adjust the morphology of ZIF-67 to cube,after introducing iron source,MOFs-derived Fe-Co-P nanoboxes were prepared through simple low-temperature phosphating treatment.The effect of metal Fe loading on the catalytic performance was studied;Third,different molybdates with rich defects was prepared on nickel foam by electrodeposition strategy,and the effects of different metal molybdate on the morphology and performance of the catalyst were discussed.The morphology and structure of the three catalysts were characterized through SEM,TEM,XRD,BET and XPS,and the electrocatalytic activity and stability of the catalysts were evaluated by CV,LSV,EIS and I-T methods.The research results showed that the three kinds of catalysts exhibit high HER and OER performance under alkaline conditions,indicating that they are potential catalysts applied in water-splitting technology.