Preparation Of Hierarchically Monolithic Silica And Silicon Carbide And Catalysis Performance

In this work,hierarchically macro/mesoporous silica monoliths(HMSM)were designed and fabricated,which were then chosen as hard templates to prepare hierarchically macro/mesoporous silicon carbide monoliths(HMSCM)by using PCS(polycarbosilane)as precursor.Various techniques such as XRD,N2 sorption,FT-IR,Raman,SEM etc,were employed to demonstrate the hierarchically porous structures of the synthesized samples.Ni(2 wt.%)/HMSM catalyst was prepared by using simple liquid impregnation route and its catalytic performance on methane-carbon dioxide reforming was investigated.It is showed that a high methane conversion of 84%under high GHSV of 15600 ml/gcatalysty/h was achieved.Meanwhile,the catalyst exhibited high stability in a long run test.On the other hand,highly dispersed Ni(2wt.%)/HMSM catalyst was prepared via incipient wetness impregnation technology.It is found that the methane conversion could arrive 90%with GHSV of 15600 ml/gcatalyst/h.Most importantly,the catalyst did not deactivate after 100h reaction.In the contract experiment,the methane conversion was found 20%lower on the catalyst without hierarchical porous structure.In addition,CuCeOx/HMSM was prepared,and 90%conversion of CO was achieved under 85 ?.Ni(2 wt.%)/HMSCM catalyst was also prepared via simple liquid impregnation method.The catalytic test showed that methane conversion was 83%under GHSV of 15600 ml/gcataiyst/h.More interestingly,Ni(2 wt.%)/HMSCM prepared super high stability,was 2%decrement of methane conversion after 150h reaction.The XRD analysis of the tested sample showed that the growing of Ni nanoparticles was effectively prohibited by HMSCM.In the start-up and stooping test.Ni(2 wt.%)/HMSCM presented high stability as well.