Synthesis, Conversion And Application Study Of Several Coordination Polymer Micro/Nano-materials

Study of nanomaterials is a hotspot in the research of the materials science and its corresponding development of nanotechnology are recognized to be one of the most promising research fields in the 21 st century.So,expanding new system,devoloping new method,fabricating new structure and exploring new application are the leading edge of nanomaterials.In recent years,the micro/nano scale coordination polymer materials have been intensively studied owing to their potential application in the fields of optical,electric,magnetic,catalytic,and so on.Recently a lot of research results show that micro/nano scale coordination polymers used as precursors for synthesis of nanomaterials,not only get various microstructures of materials,but also optimize the performance of the material.Different micro/nano structures of metal oxides,metal carbides,metal phosphide or other nanosized materials can be obtained by using coordinate polymer micro/nano materials as precursors and controlling reaction conditions of preparation.In this thesis,a series of micro/nano structures of rare earth coordination polymer have been prepared from benzenedicarboxylic acid via a facile precipitation method/solvothermal method,employing the mixture of alcohol and water as mixed solvent.After calcining in different astomspheres,a series of micro/nano rare earth oxides with various morphologies were obtained.Furthermore,we have successfully synthesized a novel bimetallic phosphide hollow nanostructured by a facile phosphidation process using Ni-Fe PBA nanocubes as the precursors and templates.The as-prepared products were well characterized and analyzed.The main content of this thesis is as following:?1?Cerium-based coordination polymers micro/nanostructures: Room temperature synthesis and their thermolysis to ceriaIn this work,several cerium-based coordination polymer micro/nanostructures such as nanoparticles,nanorods and microflowers were successfully prepared by a facile room temperature method using three isomers of benzenedicarboxylic acid as organic building block and Ce3+as center metal ion.It turns out that the three products exhibit obviously different morphologies.The topic focuses on the benzene-1,3-dicarboxylic acid,we study that the effect of pH on the structure and formation of the product within our experimental range.After calcining precursors at450 oC for 4 h,ceria with retained morphologies were achieved.Various measurements were used tocharacterize the products and their UV absorption properties were studied.?2?Fabrication of ultralong ceria nanobelts using cerium-based coordination polymer as precursors and their catalytic performanceCerium-based coordination polymer?CP?nanobelts have been prepared from benzene-1,3-dicarboxylic acid?1,3-H2BDC?and Ce?NO3?3 via a facile solvothemal method,employing cheap and non-toxic mixture of ethanol and water as solvent.The products were well characterized and analyzed.Reaction parameters such as molarratioof reactants,reaction temperature and time on the preparation were also investigated in details.CeO₂ nanobelts were obtained after calcination of the CP precursors in air at 400 °C for 4 h.The activity of catalytic reduction of p-nitrophenol for 1 wt% Pt/CeO₂ was investigated.Furthermore,other rare earth-based CP micro/nano structures were also prepared using this method.?3?Bimetallic phosphide hollow nanocubes derived from prussian-blue-analog as high-performance catalysts for the oxygen evolution reactionIn this work,using MOF?Ni-Fe Prussian-Blue-Analog?as a template and precursor,a novel and promising bimetallic phosphide catalyst?Ni0.62Fe0.38?2P is obtained via a direct phosphidation process under nitrogen atmosphere with NaH2PO₂ as the phosphorus source.Benefiting from synergistic effect between Ni and Fe species,well-defined architecture and high surface area,the as-made?Ni0.62Fe0.38?2P hollow nanocubes show a remarkable electrocatalytic performance for the OER in 1M KOH electrolyte with a low overpotential of only 290 mV at a current density of 10 mA cm-2,and a small Tafel slope of 44 mV per decade,which even surpass the benchmark Ir O₂ catalyst.Moreover,the?Ni0.62Fe0.38?2P hollow nanocubes exhibit good long-term stability.Most importantly,our facile synthetic method is appropriate for cost-effective large-scale production of hollow nanocatalysts for OER.Taken together,this study reveals that the bimetallic phosphide hollow nanocubes could be a promising OER material to replace scarcity and high cost noble metal oxides for electrochemical water splitting in the near future.