The Preparation And Electrochemical Performance In Cobalt-based Functional Materials Derived From ZIF-67 Template

Metal-organic frameworks(MOFs), known as porous coordination polymers or PCPs, are an emerging class of porous materials constructed from metal-containing nodes(also known as secondary building units, or SBUs) and organic linkers. Due to their structural and functional tunability, the area of MOFs has become one of the fastest growing fields in chemistry. MOFs can be designed to achieve specific, desired structures, moreover, unique interactions with such nanoobjects within confined nanospatial networks make nanoporous materials of particular interest for a wide variety of applications including adsorption, catalysis, electronics, and drug deliver. However, the inferior conductivity limit the widespread application in energy-related devices. For preparation of Cobalt-based functional materials on the basis of their high surface areas, adjusted pore metrics, abundant metal/organic species, and so on, ZIF-67-based in urgent energy and environment-related applications was exploited, such as lithium-ion batteries, glucose oxidation, oxygen reduction reaction and electrocatalytic water splitting was represented in this work.(1) Cobalt oxide hollow nanododecahedra(Co3O4-HND) is synthesized by a facile thermal transformation of cobalt-based metal-organic framework(Co-MOF, ZIF-67) template. When tested as a non-enzymatic electrocatalyst for glucose oxidation reaction, the Co3O4-HND exhibits a high activity and shows an outstanding performance for determining glucose with a wide window of 2.0 μM-6.06 mM, a high sensitivity of 708.4 μA mM-1cm-2, a low detection limit of 0.58 μM(S/N= 3), and fast response time(< 2 s). Based on the nonenzymatic oxidation of glucose, Co3O4-HND could be served as an attractive non-enzyme and noble-metal-free electrocatalyst in glucose fuel cell(GFC) due to its excellent electrochemical properties, low cost and facile preparation.(2) Herein, we develop a simple and scalable approach for synthesizing mondispersed Co-based zeolitic imidazolate frameworks with rhombic dodecahedral morphology at room temperatureand then obtaining high symmetric Co3O4 rhombic dodecahedra by thermal treatment of as-synthesized ZIF-67. When applied to Li-ion battery, this effective architecture was designed to maintain the integrity of the electrode material and prevent its disintegration. At the end of 20 th cycle, a dischargecharge capacity is 1030.4 mAh g-1、969.8 mAh g-1,respectively, which is much higher than both commercial graphite anodes(372 mA h g-1) and its high theoretical capacity of 890 mA h g-1.(3) Herein, the hybrid of Co nanoparticles encased by N-doped Carbon nanotube(Co@NCNT) is first prepared as a highly-active and durable no-precious metal-based multi-catalyst for hydrogen evolution reaction(HER), oxygen reduction reaction(ORR) and glucose oxidation reaction(GOR), which is fabricated by one scalable step pyrolysis of the Co-based metal-organic framework(ZIF-67) and dicyandiamide(DCDA). In order to analyse the phase, structure and component of the materials, a host of technologies, for example XRD, BET, SEM, TEM and XPS were introduced in this work. Better performances of Co@NCNT for aforementioned multi-reactions backed up by electrocatalytic experiments are mainly attributed to synergistic interactions from high conductivity of carbon, Co nanoparticles, their nitrogen dopants and robust concomitant structure. This presented strategy may open up exciting opportunities in developing highly and multifunctional electrocatalyst in electrochemical energy devices.