Synthesis And Catalytic Applications Of Metal-organic Framework Composites

Metal-organic frameworks(MOFs)are crystalline porous materials built from metal/metal-cluster-containing nodes and organic linkers.Because of their large surface area,tailorable structures and high porosity,MOFs are excellent materials for heterogeneous catalysis.To achieve the widespread applications of multifunctional materials,it is accessible to synthesize MOF composites to combine the advantages of both MOFs and various kinds of functional materials including optical,electrical,magnetic and catalytic properties to achieve synergetic effects.The synergistic combination of both MOFs and other active components could enhance the catalytic performance.In this thesis,the catalyst C₆₀Pd@Zr-NDI was designed and synthesized to achieve the synergetic effect of MOFs,C₆₀ and palladium nanoparticle in cascade reactions.Pd@HP-UiO-66 was synthesized to investigate the influence of structural defects on catalysis.Main results are as follows:1.Stable metal-organic frameworks Zr-NDI with high porosity and specific area was chosen to encapsulate palladium nanoparticle and C₆₀.Composites C₆₀@Zr-NDI,Pd@Zr-NDI and C₆₀Pd@Zr-NDI were synthesized.The obtained ternary composite C₆₀Pd@Zr-NDI exhibits enhanced catalytic performance in the cascade reactions of NH₃BH₃ dehydrogenation and hydrogenation of styrene compared to that of Pd@Zr-NDI.The influence of the addition order of C₆₀and palladium nanoparticles has been investigated.Results show that encapsulation of C₆₀ in MOFs before loading palladium nanoparticles is an important factor in improving the catalytic performance of the ternary composites.This strategy has provided a new approach for synthesizing MOF-based ternary composites with high catalytic performance,which has potential application in optics,electrics and catalysis.2.Stable UiO-66 was selected as a model to investigate the influence of structural defects on catalysis.HP-UiO-66 with different structural defects were synthesized by changing the amount and kinds of the modulators.HP-UiO-66 was used to support palladium nanoparticles to synthesize Pd@HP-UiO-66-12 Acid,Pd@HP-UiO-66-8Acid-70,Pd@HP-UiO-66-8 Acid-35 and Pd@HP-UiO-66-8 Acid-17 composites.ND-UiO-66 with no defects was synthesized.ND-UiO-66 was used to support palladium nanoparticles to synthesize Pd@ND-UiO-66.The catalytic performance of the catalyst was tested in the reduction of p-nitrophenol.When the addition amount of the modulator is moderate,catalytic activity will increase with the increasing of structural defects.Pd@HP-UiO-66-8 acid-35 with moderate structural defects exhibits the highest catalytic performance.The results demonstrate that structural defects in metal-organic frameworks could adjust the catalytic performance,and the creation of moderate structural defects is important in improving the catalytic performance.This work provides inspiration for enhancing catalytic performance with structural defects in functional materials.