Synthesis of CeO₂-Fe₂O₃ Mixed Oxides for Low-Temperature Carbon Monoxide Oxidation

Abstract

In this study, the CeO2-Fe2O3 mixed oxide catalysts have been prepared by combustion method using gel-created tartaric acid. The ability of effective carbon monoxide (CO) oxidation to carbon dioxide (CO2) by CeO2-Fe2O3 catalyst under low-temperature conditions was also demonstrated. The calcined CeO2-Fe2O3 material has a porous honeycomb structure and good gaseous absorption-desorption ability. The solid solution of CeO2-Fe2O3 mixed oxides was formed by the substitution of Fe+3 ions at some Ce4+ ion sites within the CeO2 crystal lattice. The results also showed that the calcination temperature and the molar ratio of Ce3+ ions to Fe3+ ions (CF) affected the formation of the structural phase and the catalytic efficiency. The catalytic properties of the CeO2-Fe2O3 mixed oxide were good at the CF ratio of 1 : 1, the average crystal size was near 70 nm, and the specific surface area was about 20.22 m2.g-1. The full conversion of CO into CO2 has been accomplished at a relatively low temperature of 270 °C under insufficient O2 conditions.

Unraveling the Interaction between Fe and CeO2(111) through Growth, Structure, and Thermal Stability Studies

“…For example, in the Fischer–Tropsch synthesis reaction, ceria supported Fe-based catalysts exhibit high selectivity toward light olefins. , Fe/CeO 2 catalysts also show excellent catalytic performance in selective catalytic reduction of NO x , CO oxidation, and soot oxidation, owing to the synergistic effect between iron and ceria, which was ascribed to the concepts of Ce 3+ /Ce 4+ –Fe 3+ /Fe 2+ redox couples and the enhanced reducibility of Fe–O–Ce mixed oxide. However, Fe/CeO 2 catalysts have more than one composition structure and are often mixed in catalysts. − Li et al prepared CeO 2 -supported Fe catalyst by the impregnation method, where FeO x /CeO 2– x (0 ≤ x ≤ 0.5, the same hereinafter) and Fe 2 O 3 /CeO 2 particles were detected by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) at the same time, although they believed that the coordinatively unsaturated FeO x was the only active site. Similarly, Li and Meledina et al.…”

Synthesis of Inexpensive Ternary Metal Oxides by a Co‐Precipitation Method for Catalytic Oxidation of Carbon Monoxide

“…In recent years, iron(III) oxide (Fe 2 O 3 ) has attracted much attention from researchers due to its high activity as a substrate for redox catalytic materials [6–9] . In nature, iron oxide exists in both Fe 2+ and Fe 3+ oxidation states.…”

“…[2] In recent years, iron(III) oxide (Fe 2 O 3 ) has attracted much attention from researchers due to its high activity as a substrate for redox catalytic materials. [6][7][8][9] In nature, iron oxide exists in both Fe 2 + and Fe 3 + oxidation states. The conversion ability between states of Fe 2 + and Fe 3 + becomes more flexible when they are in contact with the different chemical natures of other transition metal oxides, causing more oxygen vacancy formation and thus facilitating redox catalysis.…”

“…In nature, iron oxide exists in both Fe 2+ and Fe 3+ oxidation states. The conversion ability between states of Fe 2+ and Fe 3+ becomes more flexible when they are in contact with the different chemical natures of other transition metal oxides, causing more oxygen vacancy formation and thus facilitating redox catalysis [7] . Pure Fe 2 O 3 exhibits relatively low activity at temperatures <200 °C [10] .…”

“…The conversion ability between states of Fe 2 + and Fe 3 + becomes more flexible when they are in contact with the different chemical natures of other transition metal oxides, causing more oxygen vacancy formation and thus facilitating redox catalysis. [7] Pure Fe 2 O 3 exhibits relatively low activity at temperatures < 200 °C. [10] However, the use of Fe 2 O 3 as a support for Au/αÀ Fe 2 O 3 -hollow catalysts was proven to be effective, which refers to the formation of highly active surface species.…”