Preparation Of Functional Ordered Mesoporous Carbon Materials And Their Applications In Catalysis For Nitrobenes

Taking the advantages of high surface area,large pore volume and pore size,ordered mesoporous carbon materials have attracted much research attentions in catalysis,adsorption,hydrogen storage and electrochemistry and so on.In our study,amphiphilic carbon nanospheres,ordered mesoporous carbon material(OMC)and ordered cubic nitrogen-doped mesoporous carbon(NOMC)were successfully synthesized and utilized as efficient support for loading noble metal nanoparticles,yielding a series of excellent solid catalysts including Pt/C-400,Pt/OMC and Pt/NOMC.Scanning electronic microscope(SEM),transmission electron microscope(TEM),nitrogen adsorption,X-ray diffraction,X-ray photoelectron spectroscopy(XPS)were used to characterize the structure and properties of obtained solid catalysts.Also,the influence of different supports for the particle size distribution,catalytic activity and stability were studied.The results are listed as below:1.Through a St?ber method using fluorocarbon surfactant FC4 and triblock copolymer Pluronic F127 as templates and resorcinol as carbon precursor,ordered mesoporous phenolic resin nanospheres are successfully fabricated.The hydrophilic/ hydrophobic properties of ordered mesoporous carbon spheres could be finely engineered by controlling the carbonization temperature.Our results showed that amphipathic catalyst could be obtained by calcination at 400 oC(Pt/C-400),which exhibited superior catalytic activity than commercial Pt/C in the hydrogenation reaction of nitrobenzene.2.An ordered mesoporous carbon material was synthesized based on a solvent evaporation induced aggregating assembly approach,in which Pluronic F127 was used as template.After loading with Pt NPs by a simple impregnation method,efficient supported solid catalyst Pt/OMC could be fabricated,of which the BET surface area could be reached as high as 320 m2/g while the size of Pt nanoparticle is about 3.5 ± 1.0 nm.In the hydrogenation reaction of 4-chloronitrobenzene,the Pt/OMC catalyst showed excellent catalytic activity,and could be reused for above 5 times with >90% of conversion.3.Nitrogen-doped ordered mesoporous carbon(NOMC)with high N content,high surface area and 3D cubic structure was synthesized and utilized as efficient support to immobilize Pt nanoparticles(Pt NPs).Due to the positive effects of nitrogen element towards metal particle size,ultra-small Pt NPs(about 1.0 ± 0.5 nm)could be obtained.The supported catalyst showed excellent catalytic activity and selectivity in the hydrogenation reaction of halogenated nitrobenzenes under mild conditions,which is much higher than the commercial Pt/C catalyst.The outstanding catalytic performance might be attributed to the synergetic effects of the mesoporous structure,N-functionalized supports and the stabilized ultra-small Pt NPs.In addition,the multifunctional catalyst demonstrated excellent catalytic stability and could be reused more than 10 times without significant loss of activity and selectivity.Our results conclusively show that N-doped carbon support can offer benefits for achieving ultrafine metal nanoparticles and improving the reaction activity and selectivity.