Low-temperature oxidation of CO over Pd/CeO2–TiO2 catalysts with different pretreatments

Positive Effect of Water Vapor on CO Oxidation at Low Temperature over Pd/CeO2–TiO2 Catalyst

“…CO oxidation may follow a so-called bifunctional reaction pathway [48] at the noble metal/oxide interface; O 2 diffuses to the interface sites and reacts with CO adsorbed on the noble metal at its perimeter. The bi-functional path is also supported by the results of CO oxidation in the absence of H 2 O over the reduced Pd/CeO 2 -TiO 2 catalyst in our previous work [27], which involves the reaction between CO adsorbed on the noble metal and oxygen from ceria at the metalceria interface. The catalytic tests in this work reveal a positive effect of H 2 O on the catalytic performance of Pd/CeO 2 -TiO 2 in CO oxidation at low temperature.…”

“…The catalyst Pd/CeO 2 -TiO 2 was prepared in the similar procedures as described previously [24,27,28]. Briefly, CeO 2 -TiO 2 support was prepared through sol-gel precipitation with TiCl 4 and Ce(NO 3 ) 3 Á 6H 2 O as precursors.…”

“…The catalytic tests for CO oxidation over Pd/CeO 2 -TiO 2 catalyst were carried out in a quartz tubular flow micro reactor with an internal diameter of 6.0 mm at atmospheric pressure, with the similar procedures described previously [27,28]. Briefly, about 200 mg of catalyst sample (40-60 mesh) was used per run; the catalyst bed was about 1.0 cm in height and placed in the constant temperature zone (3-4 cm high) of the micro reactor and embedded between glass wool plugs.…”

“…Further works on the temperature-programmed reduction (TPR) using H 2 and CO as reducing agents suggested that the Pd-Ce interaction in Pd/CeO 2 -TiO 2 favored the reduction of both PdO and CeO 2 , which contributed to the high activity for CO oxidation at low temperature [24][25][26]. These works also suggested that the pretreatments of calcination and reduction might exhibit significant effects on the catalytic behavior of Pd/CeO 2 -TiO 2 [27,28]. To evaluate whether Pd/CeO 2 -TiO 2 can still perform well in CO oxidation under the relatively actual conditions, it is essential to investigate the influence of H 2 O on the CO oxidation behaviors.…”

Activation of an Ir-in-CeO2 catalyst by pulses of CO: The role of oxygen vacancy and carbonates in CO oxidation

“…CO oxidation on ceria-based catalysts has been extensively studied during the past decades, due to the high capacity of ceria to store and release oxygen as a reducible support [1][2][3][4]. Recently, a debate about the role of ceria in CO oxidation is ongoing.…”