Synthesis Of Iron-Based Composites And Their (Photo) Electrocatalytic Performance For Water Splitting

In recent years,（photo）electrocatalytic water decomposition technology has become potentially important for both energy production and environmental protection.Typically,（photo）electrocatalytic decomposition of water reactions include oxygen evolution reaction（OER）and hydrogen evolution reaction（HER）.As the OER reaction is a four-electron transfer process,the reaction is slow and the overpotential is high,so it is important to research and develop OER catalysts to reduce the hydrolysis voltage.Although noble metal-based electrocatalysts（Pt,Ru,Ir）show the best catalytic activity for electrocatalytic decomposition of water,their scarcity and high cost are huge barriers to large-scale applications.Therefore,the design and construction of resourceful,low-cost,stable and efficient non-precious metal catalysts to improve the catalytic efficiency of reactions is an urgent problem in the conversion and application of hydrogen energy.In view of this,this paper selects iron,cobalt and nickel transition metals as research objects,prepares a series of catalysts,systematically investigates their catalytic performance for decomposing water,and further explores their photoelectric catalytic performance.The main studies are as follows:（1）The Fe Co₂O₄/Ni₃S₂/NF bifunctional electrocatalyst was obtained by in situ hydrothermal fabrication of Ni₃S₂ onto a nickel foam（NF）substrate and secondary hydrothermal and calcination process.The obtained material was directly used as working electrode for OER and HER tests in 1 M KOH electrolyte.The experimental data showed an overpotential of 192 m V for OER and 158 m V for HER at a current density of 10m A/cm².In addition,the Tafel slope for OER was 54.7 m V dec^-1 and the material remained stable during 30 h stability test.（2）Building on the previous section,we further explored the electrocatalyst Fe Co₂O₄/NF,which was obtained by hydrothermal treatment to obtain Fe OOH/Fe Co₂O₄/NF,a material that not only has good electrical conductivity but also significantly reduces the overpotential of OER and HER,showing excellent electrocatalytic activity for water decomposition reactions.At current density of 10m A/cm²,the overpotential of the catalyst for OER and HER was only 242 m V and 99 m V.The decomposition voltage of water was only 1.64 V,and the catalyst also showed high stability.（3）Fe₂O₃/Zn Fe-LDH photoanodes were obtained by a impregnation method.After etching the electrode surface by plasma,the resulting Fe₂O₃/Zn Fe-LDH-plasma electrode has a substantially enhanced hydrophilicity,a photocurrent density 3.6 times higher than that of Fe₂O₃ and much improved PEC performance.These enhanced PEC properties are attributed to the good wettability of the electrode material surface,which facilitates better charge transport.