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Study of cupric oxide nanopowders as efficient catalysts for low-temperature CO oxidation

Study of cupric oxide nanopowders as efficient catalysts for low-temperature CO oxidation



CuO nanopowders were prepared by precipitation from alkaline solutions and were studied by TPRCO + O2, XRD, TGA, TPD-He and XPS. All of the precipitated samples were characterized by excellent catalytic properties toward the low-temperature (LT) oxidation of CO with similar T50 values of 110 ◦C. In contrast, bulk CuO oxides with sizes greater than 450 nm exhibited no activity at low temperatures. Several monolayers of chemisorbed species, such as water/hydroxyls and carbonate/hydrocarbonates, were typically observed at the surface of the nanopowders. These species were not critical for the LT oxidation of CO, and their preliminary removal did not substantially change the activity of the nanopowders. XPS results indicated a high deficiency of the oxygen sublattice of the CuO1−x (x = 0.1–0.15) nanopowders, whereas, for the lattice of bulk CuO, the Cu/O ratio was 1. The highly deficient oxygen sublattice resulted in a disproportionation process, which, in turn, resulted in two observed oxygen forms. An oxygen form with Eb(O1s) = 531.3 eV that is highly reactive toward CO was proposed to be responsible for the high catalytic activity of the CuO nanopowders. Slight differences in the Cu2p shake-up satellite structures were observed between the bulk and nanosized samples, which indicated that the electronic structure in the cationic sublattice had changed.Get more news about Oxide Deoxidizing Catalyst,you can vist our website!
An efficient Pd-decorated La0.8Sr0.2Co0.2Fe0.8O3-δ (LSCFO) catalyst for the catalytic deoxidation of landfill gas (LFG) at low temperature has been developed. Synergism between the Pd coating and the LSCFO substrate in inducing the catalytic deoxygen reaction (CDR) was observed. The results demonstrated that the Pd-decorated LSCFO catalysts studied showed excellent deoxygen performances and a low light-off temperature of about 225 °C, which is lower than the typical temperatures used in conventional catalytic deoxygen processes (T > 300 °C). A probable cause of this synergism may be the cooperative action when the Pd catalyst was coated on an active deoxygen substrate.

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