Preparation Of MOFs-Derived Fe-Doped Sulfur And Selenide And Their Electrocatalytic Oxygen Evolution Performance

Hydrogen energy is high in energy density,clean and environmentally friendly,and in the near future,hydrogen fuel produced by electrolysis of water will become one of the key alternative energy sources to fossil fuels.However,among them,the anode oxygen evolution reaction（OER）limits the large-scale application of electrolytic water technology due to the slow reaction kinetics.In this process,great efforts have been made in the search for efficient and low-cost non-precious metal-based electrocatalysts.Metal-organic frameworks（MOFs）have recently emerged as good precursors for the fabrication of non-precious metal-based electrocatalysts with high electrical conductivity and uniformly distributed active sites.To address these issues,in this thesis,MOFs-derived Fe-doped sulfur and selenide catalysts with large specific surface area and high catalytic activity were obtained by modulating their microstructure and electronic structure,and the relationship between their structural composition and electrocatalytic performance of electrocatalysts was systematically explored,with the main findings and conclusions as follows:1.Ni-MOF was synthesized on nickel foam by a solvothermal method using terephthalic acid as a ligand,and then Ni-MOF-based Prussian blue analogs（Ni-MOF@PBA/NF）loaded on Ni-MOF surface grown in situ on nickel foam were obtained by cation exchange reaction at room temperature.The Ni-MOF@PBA was prepared as a precursor using a hydrothermal sulfidation strategy to obtain iron-regulated Ni₃S₂（Fe-Ni₃S₂/NF）.The synthesized Fe-Ni₃S₂/NF exhibited excellent activity in alkaline media,requiring only 232 m V and 287 m V overpotentials to drive current densities of 10 m A cm^-2and 50 m A cm^-2,respectively.In addition,Fe-Ni₃S₂/NF exhibited excellent stability during OER for at least 24 h.2.Ni-BPDC was synthesized on nickel foam by a solvothermal method using biphenyldicarboxylic acid as a ligand,and then Ni Fe Prussian blue analogs（Ni-BPDC@PBA/NF）based on Ni-BPDC loaded on nickel foam were obtained by an in-situ cation exchange reaction strategy.The Ni-BPDC@PBA/NF was used as a precursor by hydrothermal selenization strategy to obtain the in situ growth of Fe-doped Ni₃Se₄（Fe-Ni₃Se₄/NF）loaded on nickel foam as an efficient and stable basic OER electrocatalyst.The doping of Fe can better modulate the electronic structure of Ni₃Se₄and increase the number of active sites and electrochemical surface area,thus improving the OER activity.Fe-Ni₃Se₄/NF exhibits excellent electrocatalytic performance in 1 M KOH with low overpotential(211 m V at 10 m A cm^-2)and small Tafel slope(34.44 m V dec^-1),which is better than commercial Ru O₂catalyst.In addition,its electrochemical properties are stable for more than 24 h at 10m A cm^-2,making it a viable non-precious metal-based electrocatalyst for alkaline OER.3.Cobalt-based zeolite imidazolium frameworks（Co-MOF）were synthesized on nickel foam at room temperature,and Co Fe Prussian blue analogs（Co Fe-PBA/NF）were synthesized by a ligand exchange reaction strategy.Fe-doped Co Ni Se₂nanosheets（Fe-Co Ni Se₂）were prepared by hydrothermal reaction using Co Fe-PBA as the precursor.Fe-Co Ni Se₂/NF exhibited excellent activity,electrocatalytic properties and outstanding stability in alkaline media,requiring only ultra-low overpotentials of245 m V and 278 m V to provide 10 m A cm^-2and 50 m A cm^-2current densities.The material also exhibits excellent stability for at least 24 h during the OER process.