Preparation And Characterization On Catalysts Of Ethanol Steam Reforming

Ethanol steam reforming is a complicated reaction system.Currently,the catalyst used for this reaction is mainly a supported metal catalyst.The main reason for the deactivation of this type of catalyst is the sintering and carbon deposition of the active components.In order to solve these problems,this article,starting with hydrotalcite-like and perovskites,conducted the following studies:NiAAl?A=Co,Y,Zr,La,Ce,Pr,Nd?hydrotalcite was prepared using nitrates of Ni,Al and doped metals Co,Y,Zr,La,Ce,Pr,and Nd as raw materials.Through investigation,it was found that NiAAl hydrotalcites doped with different ions and their derived composite oxides have great differences in structure,thermal stability and catalytic performance.The Zr-ion-doped NiZrAl hydrotalcite has higher crystallinity,while the NiCeAl hydrotalcite has good thermal stability.The NiNdAl hydrotalcite exhibited good catalytic activity in the steam reforming reaction of ethanol and can effectively promote Ethanol related chemical reactions.The compound oxides derived from hydrotalcite catalysts play an important role in the catalytic reaction,and the compound oxides derived mainly consist of the corresponding perovskite complex oxides.Therefore,the paper further examined the effect of the amount and type of ions incorporated in PrNi_xCo_1-xO₃?x=0,0.2,0.4,0.6,1?,LaNi_0.7M_0.3O₃?M=Cu,Mn,Fe,and Co?and La_0.7M_0.3NiO₃?M=Pr,Mn,Ce,Zr,and Fe?perovskite compound oxides on thier catalytic performance.The effect of the doping amount of B-site Co²⁺on the catalytic performance of PrNi_xCo_1-x-x O₃?x=0,0.2,0.4,0.6,1?catalyst has been investigated.Since the content of Co²⁺were different,thier catalytic performance were significantly different.When x=0.4,the surface structure of PrNi_0.4Co_0.6O₃ is loose,easy to restore,and it was also favorable for the dissociation of ethanol.It has good activity in the steam reforming reaction of ethanol.For LaNiO₃ series perovskites,A and B ions were doped with different ions respectively,to prepare LaNi_0.7M_0.3O₃?M=Cu,Mn,Fe,and Co?and La_0.7M_0.3NiO₃?M=Pr,Mn,Ce,Zr and Fe?series catalysts.The results showed that in the LaNi_0.7M_0.3O₃ series catalysts,the B-site doped ions had different species,and their reduction,adsorption and catalytic performance were different.The LaNi_0.7Fe_0.3O₃ catalyst doped with Fe²⁺showed good catalytic activity and resistance to carbon deposition.Similarly,there wre also great differences in the catalytic performance of different doping ion species in A site.When A site ion was doped with Fe³⁺,La_0.7Fe_0.3NiO₃ catalyst showed good catalytic activity and the conversion rate of ethanol was high,with Mn²⁺doping,the ethanol conversion on the catalyst was lower.Comprehensive comparison of each series of catalysts available,NiCeAl thermal stability is better,the conversion rate of ethanol in the reaction process remained at 88%or more;PrNi_0.4Co_0.6O₃ catalytic activity is better,but poor resistance to carbon deposition,the conversion rate of ethanol in the reaction is lower;LaNi_0.7Fe_0.3O₃ composite oxide catalyst has good thermal stability,and the special crystalline phase structure promotes the catalytic reaction,the conversion rate of ethanol is as high as 95.63%;the number of surface active centers for La_0.7Fe_0.3NiO₃ is more,and the dispersion of active centers is relatively large,a large number of gaps in the interior of the crystal structure are favorable for improving the catalytic reaction rate,and the ethanol conversion rate can reach 97.95%.LaNi_0.7Fe_0.3O₃ and La_0.7Fe_0.3NiO₃ are the better catalysts for the steam reforming of ethanol found in the study.