Synthesis Of Metal-organic Framework-derived Electrocatalysts And Their Applications In Water Electrolysis

Because hydrogen energy has the advantages of clean,pollution-free combustion products and high energy density,it is regarded as one of the most ideal alternatives to traditional fossil energy.Electrochemical decomposition of water to produce hydrogen is an effective way to achieve large-scale hydrogen production.It includes two and a half reactions of oxygen evolution reaction（OER）at the anode and hydrogen evolution reaction（HER）at the cathode.At present,the noble metals IrO₂ and RuO₂ are the best electrocatalysts for OER,while platinum metal and its alloys are the best electrocatalysts for HER.However,due to the scarce reserves and the high price,they are not suitable for large-scale industrial applications.Therefore,research and development of non-precious metal catalysts with abundant reserves has very important practical significance.Based on metal-organic frameworks（MOFs）materials,this thesis uses different control strategies to control the component structure of the catalyst in order to improve the catalytic activity of the catalyst,and then develop efficient metal-organic framework-derived electrocatalysts.The following works were specifically carried out:1.In order to improve the electrocatalytic performance of Cu-Co spinel oxide,we used CuCo-ZIF as the precursor to prepare nitrogen-doped CuCo₂O₄ nanocomposite materials（N-CuCo₂O₄@NC）.The N dopant not only improves the conductivity of CuCo₂O₄@N-C,but also increases the vacancy defect content and electrochemical active surface area.N-CuCo₂O₄@N-C exhibits excellent OER electrocatalytic activity and stability.It only needs 260 m V overpotential in alkaline electrolyte to reach a current density of 10 m A/cm2.This simple and effective heteroatom doping strategy provides a reference for the preparation of OER electrocatalysts for water electrolysis.2.In order to improve the problems of MOFs particle agglomeration and poor conductivity,this paper uses electrospinning to combine Ni Co-ZIF with polyacrylonitrile（PAN）fibers,and then prepares Nickel-doped Cobalt Phosphide@Nitrogen-Doped Porous Carbon Fiber（1D Ni-CoP@N-PCFs）composite materials by in-situ phosphating.Ni Co-ZIF particles dispersed on PAN fibers can avoid agglomeration,and the one-dimensional fiber structure is beneficial to enhance the mass transfer capacity of the reactants.After phosphating,the catalytic performance has been significantly improved.Ni-CoP@N-PCFs exhibited excellent HER electrocatalytic performance and long-term stability in both acidic and alkaline electrolytes.In this work,an efficient and low-cost HER catalyst was prepared by electrospinning.This strategy is expected to be applied to the preparation of other metal-organic framework-based electrocatalysts.