Search

A series of Mn3Co16Ox composite oxides catalysts were fabricated via a solid-phase synthesis using different manganese precursors (namely manganese acetate (A), nitrate (N), and sulfate (S)). It has been demonstrated that the obtained catalysts presented variable catalytic activities for CO oxidation and remarkable diversity of physicochemical properties closely depending on the manganese precursors. In detail, the catalytic activity and catalytic durability for CO oxidation under humid conditions generally followed a descending order of Mn3Co16Ox-A > Mn3Co16Ox-N > Mn3Co16Ox-S. The optimum catalytic performance of Mn3Co16Ox-A was predominantly attributed to its larger specific surface area, significantly higher low-temperature reducibility and lattice oxygen mobility, and more plentiful oxygen vacancies. [ABSTRACT FROM AUTHOR]

UiO-66 and its modified forms (UiO-66-NH2 and UiO-66-OH) were used as supports to prepare Rh–Mn catalysts by using a co-impregnation method, and their catalytic activities were investigated for the direct synthesis of ethanol-based C2+ oxygenates from CO hydrogenation. The catalysts were comprehensively characterized using N2 sorption, XRD, XPS, DRIFT, and TPSR analyses. The structural and textural properties of the catalysts clearly show that Rh and Mn are highly dispersed in the pores of MOFs, but the order of the original structure is partially sacrificed due to the loading of metals and the synergistic effect of Rh, Mn, and Zr would be influenced by various functional groups present in UiO-66. On combining both in situ FT-IR and TPSR analyses, it is confirmed that the higher number of active sites of Rh0 on RM/UiO-66 promotes the CO dissociation ability and hydrogenation rate, which result in its best catalytic activity with the highest yield of C2+ oxygenates, 197.3 g (kg h)−1. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT+U) was used to study the adsorption of Aux (x = 1–4) clusters on the defective CeO2(111) facet and CO adsorption on the corresponding Aux/CeO2−x catalyst, in this work Aux clusters are adsorbed onto the CeO2−x + superoxide/peroxide surface. When Au1 is supported on the CeO2(111) facet with an O vacancy, the strong electronegative Auδ− formed is not favorable for CO adsorption. When peroxide is adsorbed on the CeO2(111) facet with the O vacancy, Aux was oxidized, resulting in stable Aux adsorption on the defective ceria surface with peroxide, which promotes CO adsorption on the Aux/CeO2−x catalyst. With more Au atoms in supported Aux clusters, CO adsorption on this surface becomes stronger. During both the Au being supported on CeO2−x and CO being adsorbed on Aux/CeO2−x, CeO2 acts as an electron buffer that can store/release the electrons. These results provide a scientific understanding for the development of high-performance rare earth catalytic materials. [ABSTRACT FROM AUTHOR]

With hydrophobic properties and ordered layered structures, mono-n-dodecyloxy-phosphinyl-cerium (terbium) (MDPCT) organic–inorganic hybrid materials were synthesized using cerium nitrate, terbium nitrate and mono-n-dodecyl phosphate (MDP) surfactant with three functions, hydrophobic group and phosphorus precursor, and characterized by XRD, SEM, TEM, FTIR and PLS. The results show that the solvent affects the interlayer spacing, crystallization and luminescent intensity of the prepared MDPCT materials. MDPCT prepared in water exhibits a more ordered layered structure and a higher degree of crystallinity, as well as stronger luminescent intensity than that prepared in ethanol. Based on the excellent solubility in organic solvents, this MDPCT hybrid luminescent material will be a promising candidate for potential biomedical applications in fluorescent imaging and analysis. [ABSTRACT FROM AUTHOR]

Ca/ZrCu/ZSM-5 catalysts containing different Zr contents were prepared by incipient wetness impregnation. The catalysts were tested for the selective catalytic reduction (SCR) of NO x with ammonia and characterized by N 2 -BET, N 2 O titration, XRD, NH 3 -TPD, H 2 -TPR, and XPS techniques. In the temperature range of 100-170 °C, after calcium impregnation, NO x conversion over the Cu/ZSM-5 catalyst decreased by 11.3-24.3%, while that over Zr 0.10 /Cu/ZSM-5 only decreased by 3.8-12.2%. The improvement of the calcium poisoning resistance of the ZrCu/ZSM-5 catalyst is mainly attributed to an increase in the dispersion and the surface concentration of Cu. Moreover, the addition of zirconium promotes the reduction of CuO by decreasing the interaction between CuO and CaO, which also contributes to the improvement of resistance to CaO poisoning. The apparent activation energy and turnover frequency for the SCR reaction over the Ca/Zr x Cu/ZSM-5 catalysts were calculated and discussed., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Density functional theory (DFT+U) was used to study the adsorption of Aux (x = 1-4) clusters on the defective CeO2(111) facet and CO adsorption on the corresponding Aux/CeO2-x catalyst, in this work Aux clusters are adsorbed onto the CeO2-x + superoxide/peroxide surface. When Au1 is supported on the CeO2(111) facet with an O vacancy, the strong electronegative Au(δ-) formed is not favorable for CO adsorption. When peroxide is adsorbed on the CeO2(111) facet with the O vacancy, Aux was oxidized, resulting in stable Aux adsorption on the defective ceria surface with peroxide, which promotes CO adsorption on the Aux/CeO2-x catalyst. With more Au atoms in supported Aux clusters, CO adsorption on this surface becomes stronger. During both the Au being supported on CeO2-x and CO being adsorbed on Aux/CeO2-x, CeO2 acts as an electron buffer that can store/release the electrons. These results provide a scientific understanding for the development of high-performance rare earth catalytic materials.