Ni/ZrO₂ Catalysts Prepared By Dielectric Barrier Discharge Plasma In Dry Reforming Of Methane

In this paper,Ni/ZrO₂ catalysts,used for dry reforming of methane（DRM）,were prepared by two methods:dielectric barrier discharge（DBD）and calcination.The structure of the catalysts and catalytic performance for DRM were both compared.It was proved by the results of XRD,BET,TEM,Raman and XPS that nickel particles on plasma prepared catalyst had main exposed Ni（111）facets and smaller particles with more oxygen vacancies in support.While the calcined catalyst sintered seriously,the nickel exposed complex facets and owned larger size.The amount of oxygen vacancies also decreased obviously.At 650℃,the conversions of methane and carbon dioxide on DBD catalyst were 10%and 7%higher than calcined catalyst,respectively.When the conversion of methane attained 50%,the temperature of DBD catalyst was650℃,whearse the temperature of calcined catalyst was 700℃.Besides,the coke on used Ni/ZrO₂ prepared by DBD was half amount of that on used Ni/ZrO₂ prepared by calcination at 650℃.And coke was easier to be oxidized on DBD catalysts.Compared to traditional calcined catalyst,plasma treated catalyst has a significant improvement in the activity and coke resistance for DRM.In the process of DRM,coke on catalysts mainly came from methane decomposition.Differences of coke from methane decomposition on the two catalysts were further studied.High dispersion of nickel and exposed Ni（111）facets helped minimize the amount of coke,form amorphous carbon species and decrease the diameter of carbon nanotubes.Compared to traditionally calcined Ni/ZrO₂,the size and structure properties of catalyst prepared by plasma decomposition showed enhanced coke resistance.What’s more the experiment verified that reaction temperature,time,space velocity and reactant’s concentration could also influence the amount,species and activity of coke on catalysts.