Abstract
Suppressing the usage of rare-earth elements is crucial for making the catalysts sustainable. Preparing CeO2 nanoparticles is a common technique to reduce CeO2 consumption, but such nanoparticles are prone to sinter or react with the supports when subjected to heat treatments. This study demonstrated that stable CeO2 nanoparticles were deposited on MgO by the simple impregnation method. When CeO2/MgO was prepared under the dry atmosphere, the CeO2 nanoparticles remained ~3 nm in diameter even after being heated at 800 °C, which is much smaller than ~5 nm of CeO2/MgO prepared under ambient air. Temperature-programmed reduction, temperature-programmed oxidation, X-ray photoelectron spectroscopy, and in situ X-ray diffraction studies showed that CeO2/MgO exhibited higher oxygen mobility when prepared under the dry atmosphere. Dry reforming reaction demonstrated that CeO2/MgO prepared under the dry atmosphere exhibited higher activity than that prepared under ambient air and pure CeO2.
Highlights
Prepared under Dry Conditions andCeO2 has been used as catalysts and additives due to its high oxygen storage capacity and moderate basicity [1]
Nanorod composed of CeO2 (110) surface and cubic CeO2 nanoparticles composed of CeO2 (100) surface exhibited higher catalytic activity than conventional CeO2 nanoparticles mostly composed of CeO2 (111) surface due to higher oxygen mobility on CeO2 (110) and CeO2 (100) surfaces at low temperatures [21,22,23]
The content of CeO2 in the catalysts was calculated based on the results of inductively coupled plasma optical emission spectrometer (ICP-OES)
Summary
CeO2 has been used as catalysts and additives due to its high oxygen storage capacity and moderate basicity [1]. Nanorod composed of CeO2 (110) surface and cubic CeO2 nanoparticles composed of CeO2 (100) surface exhibited higher catalytic activity than conventional CeO2 nanoparticles mostly composed of CeO2 (111) surface due to higher oxygen mobility on CeO2 (110) and CeO2 (100) surfaces at low temperatures [21,22,23] CeO2 and Al2 O3 react to form CeAlO3 and other oxides under reducing conditions [28,29,30] Such reactions cause structural changes in the catalysts and sintering of CeO2 nanoparticles. Partial oxidation of CH4 was demonstrated over CeO2 /MgO catalysts, suggesting their stability under the reducing conditions [34,37]. This research demonstrates that CeO2 /MgO catalysts of fine CeO2 nanoparticles by controlling the atmosphere during the preparation. CeO2 /MgO catalyst outperformed pure CeO2 for dry reforming reaction the mass ratio of CeO2 in CeO2 /MgO was less than 1/5 of pure CeO2
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