Optimizing the Catalytic Performance of BaCeMnO and BaLaCuMnO Perovskites for Soot Oxidation in Simulated GDI Exhaust Conditions.

BaCeMnO (BM-Ce) and BaLaMnCuO (BMC-La) perovskite-type mixed oxides were synthesized using the sol-gel method adapted for aqueous media with different values of x (0, 0.1, 0.3, 0.

Improving the Catalytic Performance of BaMnCuO Perovskite for CO Oxidation in Simulated Cars Exhaust Conditions by Partial Substitution of Ba.

The sol-gel method, adapted to aqueous media, was used for the synthesis of BaMnCuO (BMC) and BaAMnCuO (BMC-A, A = Ce, La or Mg) perovskite-type mixed oxides. These samples were fully characterized by ICP-OES, XRD, XPS, H-TPR, BET, and O-TPD and, subsequently, they were evaluated as catalysts for CO oxidation under different conditions simulating that found in cars exhaust. The characterization results show that after the partial replacement of Ba by A metal in BMC perovskite: (i) a fraction of the polytype structure was converted to the hexagonal BaMnO perovskite structure, (ii) A metal used as dopant was incorporated into the lattice of the perovskite, (iii) oxygen vacancies existed on the surface of samples, and iv) Mn(IV) and Mn(III) coexisted on the surface and in the bulk, with Mn(IV) being the main oxidation state on the surface.

Screening BaAMnO and BaAMnCuO (A = Mg, Ca, Sr, Ce, La) Sol-Gel Synthesised Perovskites as GPF Catalysts.

BaAMnO (BM-A) and BaAMnCuO (BMC-A) (A = Mg, Ca, Sr, Ce, La) perovskite-type mixed oxides were synthesised, characterised, and used for soot oxidation in simulated Gasoline Direct Injection (GDI) engine exhaust conditions. The samples have been obtained by the sol-gel method in an aqueous medium and deeply characterised. The characterization results indicate that the partial substitution of Ba by A metal in BaMnO (BM) and BaMnCuO (BMC) perovskites: (i) favours the hexagonal structure of perovskite; (ii) improves the reducibility and the oxygen desorption during Temperature-Programmed Desorption (O-TPD) tests and, consequently, the oxygen mobility; (iii) mantains the amount of oxygen vacancies and of Mn(IV) and Mn(III) oxidation states, being Mn(IV) the main one; and (iv) for BaAMnCuO (BMC-A) series, copper is partially incorporated into the structure.

Analyzing the Effect of Zr, W, and V Isomorph Framework Substitution on ZSM-5 and Beta Zeolites for Their Use as Hydrocarbon Trap.

This work evaluates the effect on the adsorption and desorption kinetics of propene and toluene (used as probe molecules for vehicle cold-start emissions) of the isomorph framework substitution of Zr, W, and V on commercial ZSM-5 and beta zeolites. TG-DTA and XRD characterization data indicated that: (i) Zr does not modify the crystalline structure of the parent zeolites, (ii) W develops a new crystalline phase, and (iii) V causes the breakdown of the zeolite structure during the aging step. The CO and N adsorption data revealed that the substituted zeolites present a narrower microporosity than pristine zeolites.

Tailoring the Composition of BaBO (B = Fe, Mn) Mixed Oxides as CO or Soot Oxidation Catalysts in Simulated GDI Engine Exhaust Conditions.

Mixed oxides with perovskite-type structure (ABO) are promising catalysts for atmospheric pollution control due to their interesting and tunable physicochemical properties. In this work, two series of BaMnO and BaFeO (x = 1 and 0.7) catalysts were synthesized using the sol-gel method adapted to aqueous medium.

Improving the Performance of BaMnO Perovskite as Soot Oxidation Catalyst Using Carbon Black during Sol-Gel Synthesis.

A series of BaMnO solids (BM-CX) were prepared by a modified sol-gel method in which a carbon black (VULCAN XC-72R), and different calcination temperatures (600-850 °C) were used. The fresh and used catalysts were characterized by ICP-OES, XRD, XPS, FESEM, TEM, OTPD and H TPR-. The characterization results indicate that the use of low calcination temperatures in the presence of carbon black allows decreasing the sintering effects and achieving some improvements regarding BM reference catalyst: (i) smaller average crystal and particles size, (ii) a slight increase in the BET surface area, (iii) a decrease in the macropores diameter range and, (iv) a lower temperature for the reduction of manganese.

NOx Storage on BaTiCuO Perovskite Catalysts: Addressing a Feasible Mechanism.

The NOx storage mechanism on BaTiCuO catalyst were studied using different techniques. The results obtained by XRD, ATR, TGA and XPS under NOx storage-regeneration conditions revealed that BaO generated on the catalyst by decomposition of BaTiO plays a key role in the NOx storage process. In situ DRIFTS experiments under NO/O and NO/N show that nitrites and nitrates are formed on the perovskite during the NOx storage process.

BaFeCuO Perovskites as Active Phase for Diesel (DPF) and Gasoline Particle Filters (GPF).

BaFeCuO perovskites ( = 0, 0.1, 0.3 and 0.