Tuning effect of amorphous Fe2O3 on Mn3O4 for efficient atom-economic synthesis of imines at low temperature: improving [O] transfer cycle of Mn3+/Mn2+ in Mn3O4

A novel Fe₂O₃ modified Mn₃O₄ catalyst (Fe₅Mn₅-100) has been prepared by adopting a simple co-precipitation method following low temperature baking. Fe₅Mn₅-100 showed exceptionally high catalytic activity for the production of imine.

Effect of lanthanum loading on nanosized CeO2-ZnO solid catalysts supported on cordierite for diesel soot oxidation

We report the application of a solid lanthanum-ceria-zinc catalyst in the catalytic regeneration of diesel particulate filters (DPF) in diesel engines. We synthesized a CeO₂-ZnO-La₂O₃ (Ce-Zn-La) mixed oxide by a lactic acid-mediated sol-gel method, which efficiently coated cordierite substrates for soot capture and combustion. We studied the effects of La loading on the physicochemical and catalytic properties of Ce-Zn mixed oxide during low-temperature soot combustion processes. We characterized the synthesized catalysts by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N₂ adsorption, Raman spectroscopy, oxygen storage capacity (OSC), and scanning and transmission electron microscopy (SEM and TEM). Thermogravimetric and differential thermal analysis (TGA/DTA) confirmed that the catalysts effectively reduced the soot oxidation temperature. The ternary Ce-Zn-La mixed oxide catalyst with Ce/Zn/La atomic ratio of 2:1:0.5 had the highest catalytic activity and promoted soot oxidation at temperatures below 390°C. This indicated that the large number of oxygen vacancies in the catalyst structure generated oxygen species at low temperatures. Raman spectroscopy measurements revealed the presence of oxygen vacancies and lattice defects in Ce-Zn-La samples, which were key parameters concerning the stability and redox properties of the prepared catalysts.

Pt-Embedded CuO x-CeO2 Multicore-Shell Composites: Interfacial Redox Reaction-Directed Synthesis and Composition-Dependent Performance for CO Oxidation

Exploring the state-of-the-art heterogeneous catalysts has been a general concern for sustainable and clean energy. Here, Pt-embedded CuO _x-CeO₂ multicore-shell (Pt/CuO _x-CeO₂ MS) composites are fabricated at room temperature via a one-pot and template-free procedure for catalyzing CO oxidation, a classical probe reaction, showing a volcano-shaped relationship between the composition and catalytic activity. We experimentally unravel that the Pt/CuO _x-CeO₂ MS composites are derived from an interfacial autoredox process, where Pt nanoparticles (NPs) are in situ encapsulated by self-assembled ceria nanospheres with CuO _x clusters adhered through deposition/precipitation-calcination process. Only Cu-O and Pt-Pt coordination structures are determined for CuO _x clusters and Pt NPs in Pt/CuO _x-CeO₂ MS, respectively. Importantly, the close vicinity between Pt and CeO₂ benefits to more oxygen vacancies in CeO₂ counterparts and results in thin oxide layers on Pt NPs. Meanwhile, the introduction of CuO _x clusters is crucial for triggering synergistic catalysis, which leads to high resistance to aggregation of Pt NPs and improvement of catalytic performance. In CO oxidation reaction, both Pt^δ+-CO and Cu⁺-CO can act as active sites during CO adsorption and activation. Nonetheless, redundant content of Pt or Cu will induce a strongly bound Pt-O-Ce or Cu-[O _x]-Ce structures in air-calcinated Pt/CuO _x-CeO₂ MS composites, respectively, which are both deleterious to catalytic reactivity. As a result, the composition-dependent catalytic activity and superior durability of Pt/CuO _x-CeO₂ MS composites toward CO oxidation reaction are achieved. This work should be instructive for fabricating desirable multicomponent catalysts composed of noble metal and bimetallic oxide composites for diverse heterogeneous catalysis.

Effects of Mn-doped ceria oxygen-storage material on oxidation activity of diesel soot

TG and DTG curves of diesel particle shift to the low temperature region with the increase of Mn doping into CeO₂system, which indicates that the particle ignition combustion temperature decreases.

Searching for cheaper catalysts with high activity and stability in Ce–M–O systems (M = Fe, Co, Ni)

A cheaper catalyst with enhanced catalytic activity and stability was investigated among Ce–M–O (M = Fe, Co, Ni) systems.

Structural evaluation and catalytic performance of nano-Au supported on nanocrystalline Ce0.9Fe0.1O2−δ solid solution for oxidation of carbon monoxide and benzylamine

Nano-Au supported on nanocrystalline Ce_0.9Fe_0.1O_2−δ solid solution was found to show excellent catalytic performance for both CO oxidation and benzylamine oxidation.