Rational Design Of Amorphous MOFS And Mechanism Electrocatalytic Performance Improvement

There is much research focused on advanced electrochemical energy storage and conversion technologies to mitigate environmental pollution and address concerns about future energy crises.Supercapacitors,batteries,and electrocatalytic splitting of water are some of the very important technologies in this field with a constantly growing attention.The development of an efficient electrode material made of non-noble metals with good stability and behavior represents the challenge in these fields.MOFs are appealing materials because of their remarkable structural diversity,tunable pore sizes and topologies,tailorable surface chemistry,and multiple functionalities.Emerging amorphous MOFs（a MOFs）are starting as supplementary to c MOF.a MOFs retain the basic skletons and connectivity of building units.It provides rapid ion flux and uniform distribution as well as diverse pores and abundant active sites,thus accelerating mass and charge transfer during electrochemical reactions.（1）a MIL-53（Al）was synthesized by ligand competition method and a composite material a MC-x loaded with Co-LDH and p-n junction was constructed.Benefiting from the abundant oxygen vacancy of a MIL-53（Al）and heterojunction band bending,a MC-1 performs well in supercapacitors and OER,achieving A high specific capacitance of 773.2 Fg^-1at 1Ag^-1,2.23 and 44.8 times higher than the original Co-LDH and a MIL-53（Al）,respectively.In addition,the a MIL-53（Al）/Co-LDH heterojunction achieves a lower overpotential of 278m V and a smaller Tafel slope of 51.1 m V dec^-1in OER.（2）A series of ax MOF-74 were synthesized by solvent modulation method and temperature regulation.CH3CN,as a multifunctional modulation preparation,not only disturbed the normal coordination of copper ions and the original ligand to form a disordered state,but also achieved the effect of localized growth,which changed from needle rod like c MOF-74 to two-dimensional flake ax MOF-74.ax MOF-74 exhibits a larger specific surface area and accessible functional groups and metal sites,as well as imparts a flexible frame.As a result,ax MOF-74 performs well in the negative electrode of SIB and OER,and a120MOF-74achieves a lower overpotential of 310m V in OER,at the current density of 50m A g^-1with the specific capacity of 215m Ah g^-1.And outstanding stability,SIB can stable 500 cycles,can maintain about 14h in the OER reaction.