Synthesis Of Cobalt And Copper-based Metal Oxide/N-Doped Carbon Composite Nanoparticles And Photoelectric Properties

Recently,the method transforming metal-organic frameworks?MOFs?with specific structures into new type functional materials with photochemical and electrochemica l activity,such as porous carbon materials,metals,metal oxides,metal sulfides and their composites,is paid intense attention.Compared with materials transformed from other templates,these new functional materials templated with structure tunable MOFs having the following advantages:?1?larger specific surface area;?2?porous structure;?3?metal oxides could be well embedded in the carbon substrate,which will enhance their sturcture stability and photoelectric properties;?4?hetero-atom can be doped by designing the ligands of MOFs and further increase the property.With higher electron negativity and a similar atomic diameter as carbon,nitrogen is a highly attractive doping candidate for carbon materials.The introduction of N atom into carbon materials will generate extrinsic defects and more active sites,which will improve their reactivity and electronic conductivity and lead to the enhancement of ptotochemica l and electrochemical performance.As a subclass of MOFs,N-rich MOFs have been excel ent precursors for researchers to fabricate photocatalytic and electrocatalyt ic materials due to their abundant nitrogen and carbon species.Therefore,we fabricated a series of composite materials with N-doped carbon coated metal oxide nanostructure by rationally designing the MOFs templates with desired superstructures and further explored their applications in lithium ion battery and C –C bond forming reactions.The main research results are presented as following:?1?Porous N-doped carbon coated Co₃O₄ fish-scale structures were successfully fabricated via chemical transformation of a well-desinged N-rich Co-MOF at 500 °C in the nitrogen atmosphere.Due to the synergistic effect between the assembled porous Co₃O₄ nanoparticles and the N doped C coating,the sample exhibited excelle nt electrochemical properties as an anode material for lithium-ion battery.?2?N-doped Cu₂O@N-C composite was successfully obtained by simply using N-rich MOF?NTU-105?as template,whose structure is consisted of nitrogen doped porous carbon matrix as substrate and N-doped Cu2 O nanoparticles well dispersing in the matrix.Femtosecond transient absorption spectroscopy was employed to trace the lifetime of charge carriers in the N-doped Cu₂O@N-C nanoparticles,which revealed that its high photocatalytic performance relied on the long-lived holes.?3?Wel-defined cuboctahedral N-doped Cu₂O@N-C cuboctahedral core-shell nanoparticles were prepared by directly transformed from N contained cuboctahedral HKUST-1 precursor.The unique core-shell structure not only multireflect light to enhace the light adsorption efficiency,but also provides abundant highly active catalytic sites.Therefore,the N-doped Cu₂O@N-C exhibited outstanding photoredox catalytic performance and good structure stability in C–C bond forming reactions.