Effects of La2O3 contents on the Pd/Ce0.8Zr0.2O2-La2O3 catalysts for methanol decomposition
来源期刊:JOURNAL OF RARE EARTHS2011年第6期
论文作者:李雪 张利华 张超 赵明 龚茂初 陈耀强
文章页码:544 - 549
摘 要:The catalytic behaviors of Pd (1.4 wt.%) catalysts supported on CeO2-ZrO2 promoted with La2O3 were investigated for methanol decomposition. The measurements of inductively coupled plasma emission spectroscopy (ICP), N2 adsorption-desorption (BET), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and oxygen storage capacity (OSC) were used to characterize the properties of catalysts. The catalysts’ activities were tested in a fixed bed continuous flow reactor operating under atmospheric pressure. The Pd/Ce0.8Zr0.2O2-5 wt.%La2O3 catalyst exhibited the best activity. The reasons for this were twofold: (1) doping of La improved effectively textural properties of CeO2-ZrO2 oxygen storage materials, and (2) Pd/Ce0.8Zr0.2O2-5 wt.%La2O3 possessed super oxygen storage property and reducibility due to the existence of lattice defect oxygen or mobile oxygen, which helped to re-oxidize zerovalent Pd0 to a partly oxidized Pdδ+. By introducing 5 wt.%La2O3, the specific surface area of the sample increased, but declined if further increasing the content of La2O3 to 10 wt.%.
李雪,张利华,张超,赵明,龚茂初,陈耀强
Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University
摘 要:The catalytic behaviors of Pd (1.4 wt.%) catalysts supported on CeO2-ZrO2 promoted with La2O3 were investigated for methanol decomposition. The measurements of inductively coupled plasma emission spectroscopy (ICP), N2 adsorption-desorption (BET), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and oxygen storage capacity (OSC) were used to characterize the properties of catalysts. The catalysts’ activities were tested in a fixed bed continuous flow reactor operating under atmospheric pressure. The Pd/Ce0.8Zr0.2O2-5 wt.%La2O3 catalyst exhibited the best activity. The reasons for this were twofold: (1) doping of La improved effectively textural properties of CeO2-ZrO2 oxygen storage materials, and (2) Pd/Ce0.8Zr0.2O2-5 wt.%La2O3 possessed super oxygen storage property and reducibility due to the existence of lattice defect oxygen or mobile oxygen, which helped to re-oxidize zerovalent Pd0 to a partly oxidized Pdδ+. By introducing 5 wt.%La2O3, the specific surface area of the sample increased, but declined if further increasing the content of La2O3 to 10 wt.%.
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