Study On The Preparation And Catalytic Performance Of Metal Nanoparticle/Metal-organic Framework Composites

Metal-organic framework material(MOFs)have many distinct features,including ultra high specific surface area,tunable and uniform pore size,easy post-modification,et al.Due to the spatially confined effect of MOFs,MOFs are chosen as the supporters to load nano-scale metal nanoparticles by mild double solvent method in this work,the synergies of light and dynamics effect of the composite,and their use in photocatalytic and organic catalytic reaction were studied.The research content is mainly as follows:1.The as prepared of Zr-porphyrin MOF,PCN-222 was suspended in platinum precursor solution by double solvent method,and then the uniform dispersion of platinum nanoparticles were obtained by reducing platinum metal ions under light with the supplemented of optical properties of the PCN-222.The structure,morphology,valence,metal content and optical properties of Pt@PCN-222 catalysts were characterized by XRD,N2 adsorption,transmission electron microscope(TEM),plasma emission spectroscopy(ICP-AES),X-ray photoelectron spectroscopy(XPS)and electrochemical workstation.Finally,photocatalytic water splitting for hydrogen production performance was explored by under visible-light.The results show that the mesoporous Pt@PCN-222 could harvest visible-light to promote efficiently photocatalytic water splitting for hydrogen production.2.The Cr-terephthalic acid based MOF,MIL-101(Cr),were chosen as supporter to regulate the metal proportion of Pt4+/Co2+ in the channel of MIL-101 through suspending MIL-101 in different concentrations of platinum-cobalt precursor solution using double solvent method,and then Pt4+ and Co2+ were reduced by NaBH4,and then the proper concentration of nitric acid was used to selectively etch Co.The structure,morphology,metal valence and content of the catalyst was characterized by XRD,N2 adsorption,transmission electron microscope(TEM),plasma emission spectroscopy(ICP-AES),X-ray photoelectron spectroscopy(XPS)and electrochemical workstation.The catalytic performance in nmtrobenzen's hydrogenation reaction of catalysts with different proportion of Pt,Co,and defective platinum catalyst were compared.Finally,the optimal catalyst was used to expand nitrobenzene derivatives substrates,and cycle stabilty of the catalysts was investigated.It shows that Pt5(Co)64@MIL-101 with defects of Pt structure could obviously improved conversion rate of nitrobenzene hydrogenation in comparison with other catalysts,Pt(Co)@MIL-101 were well retained after three consecutive runs without any treatment or activation of the catalyst and the catalytic activity remained stable.