Study On Ni-based Porous Perovskite Catalyst For Methane Dioxide Reforming

Nowadays,the energy system in the world is mainly based on three kinds of flammable fossil resources:oil,coal and natural gas.As one of the three major fossil resources,natural gas has abundant reserves,high calorific value and is a clean energy source.At the same time,with the continuous breakthroughs in shale gas extraction technology,it provides a direction for our energy demand.The main component of shale gas is methane.With the increasing energy crisis and environmental pollution,more and more attention has been paid to the carbon dioxide reforming of methane ?DRM?,which can convert two kinds of air-polluted gases into hydrogen and carbon monoxide.The hydrogen and carbon monoxide produced simultaneously by"waste utilization"can be used as raw materials for Fischer-Tropsch synthesis and other hydrocarbons.At the same time,methane and carbon dioxide reforming reactions are conducive to carbon dioxide-rich gas fields.LaNiO₃-x-SBA-15 ?x=0,0.2,0.6,1.0? catalysts with large specific surface area are prepared by template casting method and applied to carbon dioxide reforming of methane.After TPR,XRD,TEM,TG-DSC and other characterization methods,it was found that the larger specific surface area of the catalyst,the better activity and stability of the catalyst.The reason is the larger specific surface area of the catalyst,the greater the dispersion of the active metal particles.LaNiO₃-1.0-SBA-15 has the largest specific surface area and remains active after 48 hours of stability test.Kinetic studies show that catalysts with small metal nanoparticles size exhibit higher activity,which can also inhibit carbon deposition.Nano-porous perovskite LaFe_1-xNi_xO₃ ?x=0.3,0.5,0.7? catalysts were prepared by template casting based on SBA-15 and used in carbon dioxide reforming of methane.The catalysts have larger specific surface area,and Fe element was added in the preparation process to make catalysts have a more stable perovskite structure,which will be conducive to the stability of the catalyst.Through a lot of characterization methods,it can be found that LaFe_0.5Ni_0.5O₃ with large surface area still has good activity after 80 hours testing,and there is no obvious deactivation and carbon deposition.This is because catalyst is reduced to Ni/LaFeO₃-La₂O₃ in DRM reaction.The basic additives La₂O₃ and perovskite oxide LaFeO₃ have strong interaction with active components,which reduces the surface energy of metal particles and prevents the aggregation of active Ni particles.Therefore,the catalyst has a long life.Using LaFe_0.5Ni_0.5O₃ catalyst with large surface area as template,supported with Cu?NO₃?₂ and Co?NO₃?₂,a bimetallic catalyst x%y/LaFe_0.5Ni_0.5O₃?x=6,8,10,y=Co,Cu? was prepared and used for carbon dioxide reforming of methane.After characterization,it is found that Co6-Ni and Cu8-Ni catalysts have better catalytic activity and stability.The results show that the interaction between active components and support of bimetallic catalysts hinders the diffusion and migration of active components,improves the dispersion of active components and slows down sintering.The synergistic effect between the two metals can improve the carbon deposition and sintering resistance.