Low content Pt-doped CeO2 and core-shell type CeO2/ZrO2 model catalysts; microstructure, TPR and three way catalytic activities

Development of an integrated high-voltage electron microscope-gas chromatograph-quadrupole mass spectrometer system for the operando analysis of catalytic gas reactions

This paper describes the development of a gas chromatography-quadrupole mass spectrometry system attached to a differential-pumping-type environmental cell of the reaction science high-voltage electron microscopy instrument at Nagoya University to distinguish unambiguously between different gas species with the same mass-to-charge ratio. Several model experiments were used to verify the efficacy of the newly proposed system, confirming its ability to analyse the atomic-level structural changes during heterogeneous catalysts and the associated gas-reaction kinetics simultaneously, providing new insights into operando measurements in the field of environmental transmission electron microscopy. Graphical Abstract.

Liquid-Phase Hydrogenation of Benzaldehyde on Low-Percentage Pt-Containing Catalysts under Mild Conditions

Abstract

The reaction of the liquid-phase hydrogenation of benzaldehyde is studied in two modes: at room temperature and atmospheric pressure, and at a temperature of 70°С and a pressure of 0.5 MPa on Pt/CeO2–ZrО2 catalysts with metal contents of 1 to 0.025 wt %. A 96% conversion of benzaldehyde is obtained on 1% Pt/CeO2–ZrО2 catalysts at room temperature, while a 97% conversion is obtained on 0.1% Pt/CeO2–ZrО2 catalysts at elevated temperatures. The selectivity of the formation of benzyl alcohol is in all cases 100%.

Effect of oxygen storage materials on the performance of Pt-based three-way catalysts

Pt supported on oxygen storage materials (CeO2 and CeO2–ZrO2) as effective three-way catalysts.

Study of spatial and temporal aging characteristic of catalyzed diesel particulate filter catalytic performance used for diesel vehicle

Catalyzed diesel particulate filters (CDPFs) have been widespread used as a technically and economically feasible mean for meeting increasingly stringent emissions limits. An important issue affecting the performance of a CDPF is its aging with using time. In this paper, the effects of noble metal loadings, regions and using mileage on the aging performance of a CDPF were investigated by methods of X-ray diffraction (XRD), X-ray photoelectron spectroscopy and catalytic activity evaluation. Results showed that aging of the CDPF shifted the XRD characteristic diffraction peaks towards larger angles and increased the crystallinity, showing a slowing downward trend with the increase of the noble metal loadings. In addition, the increase of the noble metal loading would slow down the decline of Pt and Pt⁴⁺ concentration caused by aging. The characteristic temperatures of CO, C₃H₈ conversion and NO₂ production increased after aging, and the more the noble metal loadings, the higher the range of the increase. But noticeably, excessive amounts of noble metals would not present the corresponding anti-aging properties. Specifically, the degree of aging in the inlet region was the deepest, the following is the outlet region, and the middle region was the smallest, which were also reflected in the increase range of crystallinity, characteristic temperatures of CO, C₃H₈ conversion and NO₂ production, as well as the decrease range of Pt and Pt⁴⁺ concentrations. The increase of aging mileage reduced the size of the aggregates of the soot and ash in CDPFs, however, improved the degree of tightness between particles. Meanwhile Carbon (C) concentration in the soot and ash increased with the aging mileage.