Preparation Of Porous Carbon Materials Supported Metal Nanoparticles Derived From Porous Organic Polymers For Catalytic Hydrogenation

Some of the earliest structural studies of porous materials were conducted in 1930 by future two-time Nobel Prize winner(Chemistry and Peace)Linus Pauling,who studied sodalite and the clay mineral mica.Scientific interest in porous materials has witnessed exceptional growth,in which porous materials play a significant role in modern chemistry,materials science,and biomedical.Porous organic polymers,as a representative of the porous materials,not only influence of the catalytic performance(e.g.,catalytic activity or selectivity)but also influences of the interface performance and electronic structure of metal nanoparticles when worked as supports of heterogeneous catalysts after been pyrolyzed to form porous carbon materials.This doctoral thesis focuses on the aspects of heteroatom doping to the porous carbon materials,controlling the metal nanoparticle size,exposing the catalytic active sites,improving the wettability and mass transfer ability of the supports,as well as disclosing the relationships between the morphology of the catalysts and catalytic performance.Then,designed and synthesized a series of porous carbon materials supported metal nanoparticles derived from porous organic polymers with excellent catalytic performance and recyclability.The main contents of this thesis are described as follows:Firstly,we were briefly introduced the conception and evolution of porous materials.Then we summarized the synthesis methods for porous carbon materials supported metal nanoparticles derived from porous organic polymers,as well as the critical technologies stabilization of metal nanoparticles and improvement of the catalytic performance.We also proposed the design ideas and implementation methods for the catalyst,attempting to address the most pressing scientific issues that currently faced.In the second chapter,we introduced a heteroatom doping strategy to prepare hyper-crosslinked polymers as precursor,then the uniformly dispersed metal nanoparticles with tunable size were successfully anchored in the aforementioned support via an in situ pyrolysis reduction strategy using heteroatom-doped hyper-crosslinked polymers and metal salt as precursors.Especially,upon a facile post-treatment process the obtained composites show the excellent catalytic performance.This method,without dangerous hydrogen reduction or activation,possessing the features of facile preparation and monomer diversity.The disadvantage is that this catalyst with a single morphology of microporous structure,which hampers the selective catalysis.In order to achieve the selective hydrogenation catalysis,we proposed the defect engineering strategy to obtain the temperature-controlled selectivity of hydrogenation and hydrodeoxygenation of biomass in chapter three.Here,we designed and synthesized nitrogen/oxygen co-doped porous carbon nanosphere derived from resin polymer spheres.After carbonization and post-treatment process,the generated abundant defects and acidic sites not only influences substrate adsorption and mass transport but also enhances surface wettability.Owing to the unique characteristics,the prepared catalysts exhibit the excellent catalytic activity and temperature-controlled selectivity for hydrogenation and hydrodeoxygenation products of biomass.It is well known that the catalytic performance of selective hydrogenation also influenced by the morphology of different catalysts.In chapter four,we prepared a series of nitrogen-doped porous carbon materials with different morphology as support based on the hyper-crosslinked block copolymer,disclosing the relationships between the morphology of catalysts and catalytic performance.We found that three dimensionally nitrogen-doped honeycomb-like porous carbon materials supported Pt nanoparticles presents significantly enhanced catalytic activities towards efficient hydrogenation of cinnamaldehyde in aqueous solutions.Furthermore,we also discussed the catalytic mechanisms.In addition to construct hierarchical structures by hyper-crosslinked diblock copolymers,herein,we proposed the method of metal nitrate mediated construction of hierarchical structure.In chapter five,we use metal nitrate as metal salt and impregnate to the resin polymer sphere to construct hierarchically porous structure,as well as in situ pyrolysis reduced during carbonization process.This method for construction of hierarchically porous structures on the one hand increased the specific surface area of the catalysts,on the other hand facilitate the mass transport ability.The as prepared magnetically-separable,versatile,and highly active carbon-based catalysts exhibit excellent catalytic performance for the selective hydrodeoxygenation of biomass under aqueous solutions.