NO Reduction by CO over Highly Active and Stable Perovskite Oxide Catalysts La_0.8Ce_0.2M_0.25Co_0.75O₃ (M = Cu, Mn, Fe): Effect of the Role in B Site

Abstract

This work focus on evaluating the influence of B site partial substitution on the physicochemical property and the catalytic property of La0.8Ce0.2M0.25Co0.75O3 (M = Cu, Mn, Fe) perovskite catalysts in NO reduction by CO. The partial substitution of B site in La0.8Ce0.2CoO3 perovskite significantly improves the catalytic performance, following the order: La0.8Ce0.2Cu0.25Co0.75O3 > La0.8Ce0.2Fe0.25Co0.75O3 ≈ La0.8Ce0.2Mn0.25Co0.75O3 > La0.8Ce0.2CoO3. The best catalytic property is achieved over La0.8Ce0.2Cu0.25Co0.75O3 catalyst at 300 °C, with 99% N2 selectivity and nearly complete conversion for NO and CO, respectively. Simultaneously, La0.8Ce0.2Cu0.25Co0.75O3 perovskite catalyst reveals the promising long-term catalytic property, compared with La0.8Ce0.2CoO3. The texture property, reducing capacity, and percentage content for oxygen defects of modified perovskites are considered as the decisive factors for the enhanced catalytic property. Moreover, giving La0.8Ce0.2Cu0.25Co0.75O3 perovskite as an example, the overall catalytic process is tentatively presented to completely understand each reaction step in NO reduction by CO.

Amorphous Boron Dispersed in LaCoO3 with Large Oxygen Vacancies for Efficient Catalytic Propane Oxidation

“…Plentiful O v result in a lower Co valency from the viewpoint of electric neutrality. According to the report by Wu and co‐workers, [48] the reversible transformation process can be summarized as Co 2+ ‐□‐Co 2+ +O 2 ↔Co 2+ ‐□‐Co 3+ ‐O 2 − ↔O − ‐Co 3+ ‐□‐Co 3+ ‐O − (□: oxygen vacancy). The presence of boron reduces the adsorption energy of oxygen molecular, hence the activation of O−O bond becomes easier.…”

Alkali Metals and Cerium-Modified La–Co-Based Perovskite Catalysts: Facile Synthesis, Excellent Catalytic Performance, and Reaction Mechanisms for Soot Combustion

“…The reduction peaks, located in the low-temperature region A, generally belong to the reduction process of Co 3+ to Co 2+ or adsorbed oxygen, while the reduction peak in region B belongs to the reduction process of Co 2+ to Co 0 or lattice oxygen. , The temperature of the reduction peaks in the lower temperature region is closely related to the catalytic performance in soot combustion, and the reduction peaks at a lower temperature can result in higher activity. For LaCoO 3 perovskite oxides, the peak at ∼350 °C is assigned to the reduction of surface Co 3+ to Co 2+ , while the peak at 390 °C can be assigned to the reduction of bulk Co 3+ to Co 2+ . In Figure A­(d), the temperature of reduction peaks in the regions A and B of the La 0.9 Ce 0.1 CoO 3 catalyst is close to that of LaCoO 3 , suggesting that the reducibility of the catalyst did not change evidently with the presence of a secondary phase CeO 2 .…”

CuCeOx/VMT powder and monolithic catalyst for CO-selective catalytic reduction of NO with CO

“…This may be due to the interaction between CuO and CeO 2 through Ce 3+ + Cu 2+ → Ce 4+ + Cu + , which parallels the XPS results. 44,45…”

“…This may be due to the interaction between CuO and CeO 2 through Ce 3+ + Cu 2+ -Ce 4+ + Cu + , which parallels the XPS results. 44,45 To further study the relationship between surface oxygen species and oxygen vacancies, we conducted an O 2 -TPD experiment (Fig. 5(b)).…”