Preparation and catalytic performance of Co3O4 catalysts for low-temperature CO oxidation

Abstract

Without use of any surfactant or oxidant, a series of Co 3 O 4 catalysts have been prepared from cobalt nitrate aqueous solution via a very simple liquid-precipitation method with ammonium acid carbonate followed by calcination at various temperatures. The catalytic performance of the Co 3 O 4 for CO oxidation has been studied with a continuous flowing laboratory microreactor system. The results show that the CO conversion of all the samples can reach 100% at ambient temperature. The catalyst calcined at 300°C is able to maintain its activity for CO complete oxidation more than 500 min at 25°C and about 240 min even at )78°C. High reaction temperature results in a high catalytic stability, while the catalytic stability decreases with further increasing the reaction temperature. Characterizations with X-ray powder diffraction and transmission electron microscopy suggest that all the samples exist as a pure Co 3 O 4 phase with the spinel structure, the samples are apt to aggregate and the specific surface area gradually decreases with increasing the calcination temperature, which directly leads to the decrease of catalytic stability. Furthermore, the amount of active oxygen species measured by CO titration experiments appears to be critical for catalytic performance.

Nanocasting Synthesis of Mesostructured Co3O4 via a Supercritical CO2 Deposition Method and the Catalytic Performance for CO Oxidation

“…Co 3 O 4 has been proven to have high catalytic activity in CO oxidation reaction [5,26]. It is reported that the catalytic activities of the Co 3 O 4 materials strongly depend on their morphologies, crystal sizes, and exposed crystal facets [3,4,27].…”

“…Cobalt oxide (Co 3 O 4 ) is a typical transition metal oxide and is widely used in catalytic oxidation reactions [5][6][7][8][9]. However, bulk Co 3 O 4 usually possesses a low surface area (*20 m 2 /g) which is unfavorable to its applications either as a catalyst or as a catalyst support.…”

Total oxidation of propene at low temperature over Co3O4–CeO2 mixed oxides: Role of surface oxygen vacancies and bulk oxygen mobility in the catalytic activity

“…In particular, Co 3 O 4 -based catalysts, studied several decades ago for the high activity for CO and VOCs oxidation [12][13][14], have received again considerable attention in the last years [15][16][17][18][19][20][21]. Doping ceria with transition metals is known to modify the redox properties, enhancing the oxygen mobility and improving the catalytic activity [22][23][24].…”

Effect of CeO2 Doping on Structure and Catalytic Performance of Co3O4 Catalyst for Low-Temperature CO Oxidation

“…As a promising candidate of precious metal catalysts, cobalt oxide catalysts have attracted considerable attentions because of not only its high activity for CO and hydrocarbon oxidation [18,19], but also its use in the Fischer-Tropsch synthesis [20], NO decomposition [21], and ammonia oxidation [22]. The low-temperature CO oxidation over single component, composite and supported cobalt oxide catalysts have been studied [12][13][14][15][16][17][18], and these cobalt oxides show significant catalytic activity for CO oxidation.…”