Chemoselective hydrogenation of cinnamaldehyde over a tailored oxygen-vacancy-rich Pd@ZrO2 catalyst

Selective hydrogenation of cinnamaldehyde to hydrocinnamaldehyde is captivating due to its industrial relevance.

Nanostructured Equimolar Ceria-Praseodymia for Total Oxidations in Low-O2 Conditions

A Gasoline Particulate Filter (GPF) can be an effective solution to abate the particulate matter produced in modern direct injection gasoline engines. The regeneration of this system is critical, since it occurs in oxygen deficiency, but it can be promoted by placing an appropriate catalyst on the filter walls. In this paper, a nanostructured equimolar ceria-praseodymia catalyst, obtained via hydrothermal synthesis, was characterized with complementary techniques (XRD, N2-physisorption, FESEM, XPS, Temperature Programmed Reduction, etc.) and its catalytic performances were investigated in low oxygen availability. Pr-doping significantly affected ceria structure and morphology, and the weakening of the cerium–oxygen bond associated to Pr insertion resulted in a high reducibility. The catalytic activity was explored considering different reactions, namely CO oxidation, ethylene and propylene total oxidation, and soot combustion. Thanks to its capability of releasing active oxygen species, ceria-praseodymia exhibited a remarkable activity and CO2-selectivity at low oxygen concentrations, proving to be a promising catalyst for coated GPFs.

Combustion of lean methane over Co3O4 catalysts prepared with different cobalt precursors

To investigate the effect of catalyst precursors on physicochemical properties and activity of lean methane catalytic combustion, a series of Co₃O₄ catalysts were prepared via a precipitation method by using four different cobalt precursors: Co(C₂H₃O₂)₂, Co(NO₃)₂, CoCl₂, and CoSO₄. The catalysts were characterized by BET, XRD, SEM, Raman, XPS, XRF, O₂-TPD and H₂-TPR techniques. It was found that the different types of cobalt precursor had remarkable effects on the surface area, particle size, reducibility and catalytic performance. In contrast, the Co₃O₄-Ac catalyst showed a relatively small surface area, but its activity and stability were the highest. XPS, Raman, O₂-TPD and H₂-TPR results demonstrated that the superior catalytic performance of Co₃O₄-Ac was associated with its higher Co²⁺ concentration, more surface active oxygen species and better reducibility. In addition, the activity of the Co₃O₄-S catalyst reduced significantly due to the residual impurity SO₄²⁻, which could reduce the concentration of surface adsorbed active oxygen species and inhibit oxygen migration.

The effects of cobalt precursor on the microstructure, surface properties, reducibility and catalytic performance for methane combustion were investigated.

Fabrication of Monolithic Catalysts: Comparison of the Traditional and the Novel Green Methods

Monolithic catalysts have great industrial application prospects compared to powdered catalysts due to their low pressure drop, the high efficiency of mass and heat transfer, and recyclability. Deposition of active phases on the monolithic carriers dramatically increases the utilization rate and has been attracting continuous attention. In this paper, we reviewed the traditional (impregnation, coating, and spraying) and novel (hydrothermal and electrodeposition) strategies of surface deposition integration, analyzed the advantages and disadvantages of both ways, and then prospected the possible directions for future development of integration technologies.