Preparation And Application Of Organic Frameworks Supported Novel Metal Catalysts

Porous organic frameworks are a series of novel materials with functionaldesigned propertities, which have been extensively used in many fields like gasstorage and separation, opto-sensor and electronic sensor, functional materials,catalysis and others. So far, a bottleneck for the application of porous organicframeworks in catalysis is the thermal instability at elevated temperature, requiredwith those operations for catalyst preparation (like reduction by hydrogen andcalcination). It is highly necessary to develop novel techniques that can be operated atlow temperature conditions (less than200C normally) for the synthesis of catalystssupported on porous organic frameworks. In the present work, a new technology thatallows room temperature reduction for the preparation of supported noble metalcatalysts via glow discharge plasma has been developed very recently with electron asreducing agent. It is a green and simple way for reduction of metal ions at ambienttemperature. Then, the metal loaded catalysts are synthersized with small particle size.The interaction between metal particles and supports as well as the amorphizationprocedure by heating are discussed. The catalytic activity of these catalysts aremeasured based on CO oxidation reaction and selective benzyl alcohol oxidationreaction, resperically.By using argon glow discharge plasma technique, Ag/Cu-BTC catalyst isprepared under ambient temperature. XRD characterization reveals no changes in thecrystal structure of the support except the removal of axially coordinated waterconnected to Cu. Silver particles are highly dispersed in the framework with smallsize. Thermal treatment of Cu-BTC supported Ag has been performed at250oC andambient pressure under oxygen atmosphere. Ag/CuxO (x=1,2) nanoparticles areobtained. The catalyst characterization shows that CuO and Cu2O species are helpfulfor CO adsorption and Ag plays a key role in the activation of oxygen. The synergybetween CuxO and Ag leads to significantly enhanced activity for CO oxidation. Inaddition, Ag is partially oxidized by oxygen and Ag2O probably acts as one of theactive species for CO oxidation.The covalent tetrazine-based framework (TzF-9) supported palladium ion isreduced by the electrons generated by room temperature glow discharge plasma. TEM images show that an ultra-high dispersion of palladium nanoparticles with a particlesize smaller than1.5nm has been achieved. The role of nitrogen in stabilizing thenanoparticles is proved by FT-IR, Raman and DFT. The as-synthesized Pd/TzF-9catalyst shows a good activity for selective oxidation of benzyl alcohol.