Design,Synthesis And Catalytic Property Of Transition Metal Nanocatalysts(FePt,Ru)

With the continuous development of energy,pharmaceutical and other industries,the demand of metal nanocatalysts is increasingly urgent.It is of significant meaning and practical value to design and prepare highly efficient and stable metal nanocatalysts for promoting the industry,science and technologydevelopment.Noble metals usually show high intrinsic activity in most chemical reactions,however,the large-scale application of noble metal catalysts is a trouble because of their scarce reserves.It is an effective way to address the above issue by designing catalyst structure,regulating the content of catalyst components,improving the catalytic activity and exploring the key factors affecting the performance of of noble metal catalysts.Therefore,based on the above research background,this paper aims at designing and preparing highly efficient and stable catalysts.1.Synthesis and characterization of Fe-containing monometallic polymers and FePt-containing heterobimetallic polymers.Fe-containing polymers and FePt-containing polymers were synthesized from ferrocenecarboxaldehyde and potassium tetrachloroplatinate by multi-step organic chemical reactions.The structure and thermal stability of the intermediates and the final polymers were characterized by ¹H NMR,IR absorption spectroscopy and thermogravimetric analysis.The results indicate that all polymers show good thermal stability with the onset thermal decomposition temperature of Fe-P higher than 225 ^oC,and FePt-P higher than 300 ^oC.2.Preparation and characterization of FePt NPs.A series of FePt metal alloy nanoparticles?FePt NPs?were synthesized by pyrolyzing FePt-containing polymers at different temperatures?500-1000 ^oC?,recorded as FePt-500,FePt-600,FePt-700,FePt-800,FePt-900,FePt-1000,respectively.X-ray diffraction?XRD?spectra analysis showed that of the resulting FePt NPs is L1₀ phase.It can also be found that,the crystallinity of FePt NPs increased with the increase of pyrolysis temperature.Transmission electron microscope?TEM?images showed that the average particle sizes of FePt NPs changed with the increase of pyrolysis temperature.Thermogravimetric analysis manifest that the as-synthesized FePt NPs have good thermal stability with the onset decomposition temperature higher than 325 ^oC.3.Study on the electrocatalytic performance of FePt NPs.In this work,FePt NPs were used as cathode catalysts for hydrogen evolution reaction?HER?and oxygen reduction reaction?ORR?,respectively.The polarization curve of HER in acid electrolyte showed that FePt-900 with the overpotential of 34 mV at the current density j=10 mA cm^-2,which is very close to the 28 mV of commercial Pt/C?10 wt%?.We preliminarily believe that the particle size and crystallinity together determine the HER activity of FePt NPs.In ORR test,it is found that FePt-800 with the initial potential of 0.93 V and half-wave potential of 0.73 V.We assume that the main factor affecting the activity of FePt NPs in ORR is particle size.4.The hydrogenation of aromatics is an important reaction in the synthesis of fine chemicals.Ru nanocatalysts loaded on PN-CeO₂?Porous nanorods CeO₂?,NR-CeO₂?Nanorods CeO₂?,NP-CeO₂?Nanoparticles CeO₂?,SiO₂ and TiO₂were prepared in this work,which recorded as Ru NPs/PN-CeO₂,Ru NPs/NR-CeO₂,Ru NPs/NP-CeO₂,Ru NPs/SiO₂ and Ru NPs/TiO₂,respectively.The mass loading amount were 1 wt%.In the hydrogenation of Ethyl benzoate,Ru NPs/PN-CeO₂ exhibits the highest catalytic activity as well as the 100%selectivity for hydrogenation of aromatics,while Ru/SiO₂ and Ru/TiO₂ had no hydrogenation activity at all.5.In order to prepare the catalysts with high activity and selectivity for hydrogenation of naphthalene,Ru nanocatalysts loaded on activated carbon,carbon black and carbon nanotubes were prepared,recorded as Ru NPs/AC,Ru NPs/VXC72?carbon black?and Ru NPs/CNT,respectively.The mass loading amount were 5%,and the average particle size were less than 2 nm.We found that Ru nanoparticles loaded on different carbon carriers showed significantly different catalytic properties.Ru/AC NPs exhibit the highest catalytic activity.