Effects of preparation methods on catalytic performances of Cu/Ce0.8Zr0.2O2 catalysts for methanol steam reforming to produce hydrogen
The preparation methods can affect the type and dispersion of Cu species,as well as the interaction between Cu species and supports in catalysts.Cu/Ce0.8Zr0.2O2 catalysts with Ce0.8Zr0.2O2 sosolid as the support and Cu loading(mass fraction)of 15％were prepared by deposition precipitation,ammonia evaporation,impregnation and co-precipitation methods,respectively.The phase compositions,texture properties,Cu dispersions and microstructures of the catalysts were characterized by XRD,N2 physical adsorption/desorption,N2O titration,SEM,etc.And the catalytic performances of the catalysts for methanol steam reforming to produce hydrogen were evaluated in a fixed-bed reactor.The results show that compared with the Cu/Ce0.8Zr0.2O2 catalysts prepared by another three methods,the Cu/Ce0.8Zr0.2O2 catalyst(Cu/Ce0.8Zr0.2O2-DP)prepared by deposition precipitation method has the largest specific surface area(82.5 m2/g)and Cu specific surface area(206.0 m2/g),as well as the highest Cu dispersion(30.5％).Under the reaction conditions of 250 ℃,atmospheric pressure,n(deionized water)∶n(methanol)of 1.3∶1.0 and liquid space velocity of 6 mL/(g·h)for 24 h,Cu/Ce0.8Zr0.2O2-DP shows relatively optimal catalytic performance with methanol conversion rate of 95.2％,hydrogen production rate of 286.8 mmol/(g·h)and CO selectivity of 0.86％.
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