Effect of calcination temperature on properties of Cu/ZnO/Al₂O₃/ Cr₂O₃+H-ZSM-5 bi-functional catalysts for steam reforming of dimethyl ether

The Cu/ZnO/Al₂O₃/Cr₂O₃+H-ZSM-5 performances for hydrogen production during dimethyl ether steam reforming (DME SR) were investigated,which was prepared by the co-precipitation coupling with mechanical mixing method.Meanwhile, the effect of calcination temperature on the physicochemical properties of catalysts were studied by thermogravimetry, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller, and H₂ temperature-programmed reduction.It was revealed that Cu/ZnO/Al₂O₃/Cr₂O₃ catalyst was decomposed at 400℃ to form CuO and sponel phase that played a key role in separating the Cu during the reaction.Under lower calcination temperatures,the catalyst was incompeletely decomposed.Increasing the calcination temperature to over 500℃ caused severe sintering of CuO and facilitated the formation of spinel phase, which led to a significant decrease in the number of active sites.When the calcination temperature was controlled at 400℃, the biggest DME conversion rate of 92.9% and hydrogen yield of 76.5% was reached.