Highlights-BaTiO3 and BaTi0.8Cu0.2O3 perovskites were synthesized using sol-gel and hydrothermal methods.-The location of copper in the catalyst depends on the synthesis method.-Cu-BTOsg, with Cu incorporated into the structure, presents a high NOx storage capacity.-Cu-BBOH, with CuO highly dispersed on the surface, shows a high activity for NO to NO2 oxidation. This is a previous version of the article published in Applied Catalysis A: General. 2016General. , 519: 7-15. doi:10.1016General. /j.apcata.2016 2 AbstractThe effect of the synthesis method (hydrothermal and sol-gel) on the properties of BaTi0.8Cu0.2O3 perovskites as catalysts for NOx and soot removal has been analyzed. X-ray powder diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), ICP-AES, N2 adsorption at -196ºC, Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) and temperature programmed reduction with hydrogen (H2-TPR) have been used for catalysts characterization.To test their catalytic activity, NOx storage and soot combustion temperature programmed reaction tests have been carried out.The results allow to conclude that the synthesis method determines the position of copper on the perovskite structure and, therefore, the catalytic applications. When the hydrothermal method is used the copper is highly dispersed on the perovskite surface, obtaining a catalyst with a high activity for the NO to NO2 oxidation reaction, which can be used as oxidation catalyst for soot removal. Nevertheless, using the sol-gel method, copper is incorporated into the perovskite structure and, consequently, the catalyst presents a high NOx storage capacity

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A series of Pt x -Sn y /C catalysts with different atomic ratios (x:y = 1:1, 2:1, 3:1) and diameters (~4 nm) were easily synthesized by a deposition process using formic acid as the reducing agent.Catalyst structure and chemical composition were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). XRD and SEM showed that the geometric environment was changed with Sn addition to the fcc Pt crystallites by forming a solid solution of Pt-Sn alloy phase for Pt 1 -Sn 1 /C catalyst, while for Pt 3 -Sn 1 /C and Pt 2 -Sn 1 /C, a decrease in Pt 4f binding energy was observed, and from the XPS results was attributed to charge transfer from Sn to Pt.From TEM results, it could be seen that Pt nanoparticles could be easily synthesized, even at a high metal load, without the use of expensive surfactants. The electrochemical behavior of catalysts during ethanol oxidation in acidic media was characterized and monitored in a half-cell test at room temperature by cyclic voltammetry, chronoamperometry, and anode potentiostatic polarization. The amount of Sn added affected the physical-chemical characteristics of the bimetallic catalysts; however, these catalysts did not show differences in the electrocatalytic activity towards ethanol oxidation. The presence or absence of alloy was a function of the Sn content on catalysts for the preparation method used. The behavior presented for Pt x -Sn y /C catalysts can be attributed to the so-called bifunctional mechanism, and to the electronic interaction between Pt and Sn.

The effect of the synthesis method (sol-gel or hydrothermal) in the physicochemical properties of a BaTi 0.8 Cu 0.2 O 3 catalyst with perovskite structure was analyzed and the catalytic performance for the NO-NO 2 oxidation and for the NO x storage was tested. The characterization of catalysts by BET, ICP-OES, XRD, XPS and H 2 -TPR reveals that only the sol-gel process allows the incorporation of copper into the perovskite structure, and that, by using the hydrothermal method, highly dispersed CuO is deposited on the surface of the BaTiO 3 . The NO x storage cyclic (NSC) experiments, carried out using both catalysts, indicate that sol-gel catalyst shows a high NO x storage capacity at 400°C whilst the hydrothermal catalyst exhibits a high NO to NO 2 oxidation activity. For this reason, a double bed reactor configuration was tested for NSC experiments using the hydrothermal catalyst as the oxidation catalyst and the sol-gel catalyst as the NO x trap.