Preparation And Electrocatalytic Oxygen Evolution Performance Of MOF-based Self-supported Nanocatalysts

Metal organic frameworks have attracted extensive attention in the fields of gas adsorption,energy conversion and electrocatalysis because of their unique 3D porous structure,large specific surface area,highly adjustable composition and topology.However,the poor conductivity,the destruction of the inherent structure of MOF caused by pyrolysis strategy and the agglomeration between particles have caused great obstacles to the application of MOF.In this paper,a series of inexpensive metal MOF based nanomaterials with low cost and excellent properties have been constructed using a simple hydrothermal method or solution method.In addition,the structure and catalytic performence of the materials are further studied.This work broadens the application of MOF materials in the field of catalysis and may open up a new strategy for the preparation of electrocatalysts with low cost and high activity.The specific research content is as follows:(1)2D bimetallic ultra-thin nanosheets(Ni Fe-MOF/IF)were fabricated in situ on the surface of foamed iron(IF)by one-step hydrothermal method and applied directly to electrocatalytic water splitting.The results show that Ni Fe-MOF/IF nano array displays excellent OER performance under alkaline conditions,only an ultralow overpotential of 230and 262 m V were required to achieve the current density of 10 and 100 m A·cm^-2,with excellent stability.The outstanding electrocatalytic performance of Ni Fe-MOF/IF may be attributed to the effective combination of its 3D high porosity and conductive substrate;in situ growth of Ni Fe-MOF/IF;the strong coupling between Ni Fe bimetals and the unique ultra-thin2D nanosheet structure.This work broadens the application of MOF materials in the field of OER catalysis,and the in-situ growth strategy with certain universality can be applied to other fields.(2)A self-supporting binder free electrocatalyst Cu(OH)₂@ZIF-67/CF was successfully synthesized by the combination of ZIF-67 nanoparticles with in-situ grown Cu(OH)₂nanowires through a simple room temperature assembly method.The as-prepared Cu(OH)₂@ZIF-67/CF exhibits excellent OER performance under alkaline conditions,only requiring overpotentials of 205 m V and 276 m V to reach the current densities of 10 m A cm^-2and 100 m A cm^-2.The unique 3D structure formed by the combination of Cu(OH)₂nanowires and porous ZIF-67 may produce larger electrochemical active surface area and expose more active sites.The synergy between the unique structure of MOF and conductive substrate can adjust the electronic structure and accelerate the transfer of electrons,so as to greatly improve the electrocatalytic OER performance and durability.This work may provides a feasible strategy for the rapid preparation of low-cost and efficient OER catalysts at room temperature.