Simultaneous catalytic removal of NOx and diesel soot particulates over La2−xAxNi1−yByO4 perovskite-type oxides

BaFe1−xNixO3 Catalysts for NOx-Assisted Diesel Soot Oxidation

In this work, it is analyzed the effect of the partial substitution of Fe by Ni in a BaFeO3 perovskite to be used as the catalyst for NOx-assisted diesel soot oxidation. A series of BaFe1−xNixO3 (x = 0, 0.2, 0.4 and 0.8) catalysts have been synthesized by using the sol–gel method. The catalysts have been characterized by ICP-OES, XRD, XPS, O2-TPD, H2-TPR- and TEM. The catalytic activity for NO to NO2 oxidation and NOx-assisted diesel soot oxidation have been determined by Temperature Programmed Reaction experiments (NOx -TPR and Soot-NOx-TPR, respectively) and by isothermal reaction at 450 °C. Ni seems not to be inserted in the BaFeO3 perovskite and, instead of that, BaNiO3 perovskite and NiO are detected on the surface of the perovskite BaFeO3. XPS data reveal the coexistence of Fe(III) and Fe(IV) on the catalyst’s surface (being Fe(III) the main oxidation state) and the presence of oxygen vacancies. All catalysts are active for NO oxidation to NO2, showing BaFeO3 and BaFe0.6Ni0.4O3 the best catalytic performance. BaFe0.6Ni0.4O3 shows the highest proportion of nickel on surface and it combines the highest activity and stability for NOx-assisted diesel soot oxidation. Also, this catalyst presents the highest initial soot oxidation rate which minimizes the accumulation of unreacted soot during reaction.

A Review on the Catalytic Decomposition of NO by Perovskite-Type Oxides

Direct catalytic decomposition of NO has the advantages of being a simple process, producing no secondary pollution, and being good for the economy, which has attracted extensive research in recent years. Perovskite-type mixed oxides, with an ABO3 or A2BO4 structure, are promising materials as catalysts for NO decomposition due to their low cost, high thermal stability, and, of course, their good catalytic performances. In this review, the influence factors, such as A-site substitution, B-site substitution and reaction conditions on the catalytic performance of catalysts have been expounded. The reaction mechanisms of direct NO decomposition are also discussed. Finally, major conclusions are drawn and some research challenges are highlighted.

In-situ modified the surface of Pt-doped perovskite catalyst for soot oxidation

In-situ modification is studied in this work on LaCo_1-xPt_xO₃ for soot oxidation. A series of perovskite catalysts LaCo_1-xPt_xO₃ (by sol-gel method) are modified with 30% H₂O₂. XRD, TEM, SEM, BET, XPS, Raman, in-situ DRIFTS, H₂-TPR and TGA are used to investigate physicochemical properties of catalysts. TGA results show that all doped catalysts have a lower temperature of soot conversion, especially LaCo_0.94Pt_0.06O₃ (T₅₀ = 437 °C). The T₅₀ of the catalyst with modification by H₂O₂ solution decreases at least 20 °C compared with the doped catalysts. A highly symmetrical structure and an obvious amorphous layer about 3-5 nm are observed in the modified catalysts. According to the XPS study, the symmetrical structure benefits to the movement of oxygen vacancy thus catalyst captures more adsorbed oxygen (about 95%). And the amorphous surface could adsorb more oxygen species. In addition, all catalysts show excellent aging resistance performance. The reaction mechanism of catalyst for soot oxidation is presented in the end.

Perovskite-based catalysts for the control of nitrogen oxide emissions from diesel engines

Nitrogen oxides removal over a wide range of perovskite-based catalysts together with their property-activity relationships.

The effect of A-site doping in a strontium palladium perovskite and its applications for non-enzymatic glucose sensing

The catalytic activity of a strontium palladium perovskite, Sr₂PdO₃, toward non-enzymatic glucose sensing is strongly affected by the Sr²⁺ A-site partial substitution by Ca²⁺ ions; Sr_2−xCa_xPdO₃ with x = 0–0.7.

Three-dimensionally ordered macroporous spinel-type MCr2O4 (M = Co, Ni, Zn, Mn) catalysts with highly enhanced catalytic performance for soot combustion

MCr₂O₄ catalysts with three-dimensional ordered macroporous structures displayed superior catalytic activity for soot combustion to their bulk counterparts.

Doped lanthanum nickelates with a layered perovskite structure as bifunctional cathode catalysts for rechargeable metal-air batteries

Rechargeable metal-air batteries have attracted a great interest in recent years because of their high energy density. The critical challenges facing these technologies include the sluggish kinetics of the oxygen reduction-evolution reactions on a cathode (air electrode). Here, we report doped lanthanum nickelates (La2NiO4) with a layered perovskite structure that serve as efficient bifunctional electrocatalysts for oxygen reduction and evolution in an aqueous alkaline electrolyte. Rechargeable lithium-air and zinc-air batteries assembled with these catalysts exhibit remarkably reduced discharge-charge voltage gaps (improved round-trip efficiency) as well as high stability during cycling.