Hierarchy Bi-Metal Electrode Modified Materials Derived From Metal Organic Framework And Its Electro-Catalytic Property

Emerging as a new class of porous crystalline materials,MOFs,constructed by alternatively connecting metal ions with organic struts.Over the past few decades,MOFs have become a rapidly developing research area and have attracted many attentions in many scientific fields due to their ordered frame structure,large spacific surface area and rich pore structure.Previous studies have focused on the design and synthesis of MOFs materials with different morphologies,structures and functions,and so as to explore their possibilities in applications such as gas adsorption and storage,catalysis,medicine,sensing and identification.In recent years,the postprocessing of MOFs materials are more popular in material science,the metals or organic ligands in MOFs can be used to prepare metal/metal oxides or porous carbons under certain conditions.On the one hand,MOFs have low thermal stability and chemical stability,hence MOFs can be decomposed into its corresponding metal oxides and porous carbon materials under certain conditions.On the other hand,the MOFs materials have the rapid development and the diversity of the building unit,so that its postprocessing products diversified and have a variety of functions.Thus in this paper,a series of composite metal oxides and carbon-encapsulated bi-metallic nanoparticles materials were prepared by facile posttreatment,and their electrocatalytic properties were studied.?1?Uniform Ce-MOF micro-nanorods with different sizes were synthesized by controlling the reaction time by solvothermal method.Then,Ce_1-xTb_x-MOF crystals were synthesized by introducing a second rare earth metal Tb into the metal center of Ce-MOF.And then Ce_1-xTb_xO_y micro-nanorod particles were synthesized by direct thermal decomposition of Ce_1-xTb_x-MOF precursor in air,and the effects of precursor's pyrolysis temperature and the ratio of different metals on the physical and chemical properties of Ce_1-xTb_xO_y were also explored.It was found that the Ce_0.9Tb_0.1O_y micro-nanorod particles obtained by thermal decomposition at 400°C from Ce_0.9Tb_0.1-MOF micro-nanorods prepared at 10 min had higher specific surface area and strong electron transfer capability.The catalytic activity of CeO₂ and Ce_0.9Tb_0.1O_y modified GCE?Glassy carbon electrode?for sensitive H₂O₂ detection were compared,and composite metal oxide Ce_0.9Tb_0.1O_y showed good sensitivity(12.99?A?mM?cm^-2),low detection limit?7.7?M?,wide linear range?0.1⁴.2 mM?and better cycle stability due to the co-coupling between bimetallic.The preparation of composite metal oxides by precursor method can be extended to the preparation of other composite metal oxides,which is of great academic significance and value for the synthesis of nano-metal oxides.?2?Uniform Co-ZIF nanocrystals with different sizes were synthesized by solvothermal method.Ni_xCo_1-x-ZIF crystals with single metal Co-ZIF structure were synthesized by introducing a second transition metal Ni into the metal center of Co-ZIF.Then the carbon-encapsulated bi-metal sites composite materials were prepared by carbonization of bimetallic ZIFs precursors under inert atmosphere.A series of influencing factors such as the synthesis temperature of precursors ZIFs,metal ratio,carbonization temperature,atmosphere and post-treatment on the physical and chemical properties of the carbon materials were investigated.Then the hydrogen production activity of Co@N-Cs₈₀₀-b and Ni_0.4Co_0.6@N-Cs₈₀₀-b modified GCE were compared in alkaline solutions.The results shown that the Ni_0.4Co_0.6@N-Cs₈₀₀-b material obtained by carbonization under the following conditions?Ni:Co ratio was 2:3,carbonization temperature was 800°C and under Argon flow?exhibited a lower overpotential of 68 mV at a current density of 10 mA?cm^-2 and excellent cycling stability,while the overpotential of Co@N-Cs₈₀₀-b was 94 mV at a current density of 10 mA?cm^-2.This low overpotential and excellent cycling stabiliy are due to the co-coupling between bimetallic and the high conductivity of the carbon material.