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Effective glyceric acid production from glycerol was demonstrated under mild conditions in an open-air system at room temperature in the absence of base or oxygen gas flow by employing a Pt/CeO2–ZrO2–Fe2O3/Santa Barbara Amorphous No. 16 (SBA-16) catalyst. At a low loading amount of CeO2–ZrO2–Fe2O3 (16 wt%Ce0.64Zr0.16Fe0.20O2−δ/SBA-16), the oxygen release and storage abilities and high acidity of the catalyst afforded a high glyceraldehyde yield, owing to the enhancement of the oxidation ability of the Pt activator and the acceleration of the desorption of glyceraldehyde. The increase in CeO2–ZrO2–Fe2O3 loading amount further improved the oxygen release and storage abilities and lowered the catalyst acidity induced by crystallite growth and particle aggregation. The high oxygen release and storage abilities, as well as the low acidity, contributed to the high glyceric acid yield; the highest activity for glyceric acid production was obtained for the 7 wt%Pt/40 wt%Ce0.64Zr0.16Fe0.20O2−δ/SBA-16 catalyst. The glyceric acid yield increased up to 68.2% after 10 h of reaction in atmospheric air at 30°C. [ABSTRACT FROM AUTHOR]

The size effect of the ZrO2 support on the catalytic activity for the liquid-phase oxidation of phenol was demonstrated over Pt/CeO2-ZrO2-Bi2O3/ZrO2-X catalysts. Here, we selected six types of size-controlled ZrO2-X (X: A–F) (ZrO2-A: 35 nm, ZrO2-B: 22 nm, ZrO2-C: 14 nm, ZrO2-D: 11 nm, ZrO2-E: 9 nm, and ZrO2-F: 2 nm). The surface area of the ZrO2-X support was inversely proportional to the particle size of ZrO2. ZrO2-X (X: A–E) were crystalline phases, while ZrO2-F was amorphous phase. For Pt/CeO2-ZrO2-Bi2O3/ZrO2-X (X: A–E) catalysts, the smaller particle size of the crystalline ZrO2 (X: A–E) support resulted in a larger catalyst surface area, which in turn led to enhanced oxygen release and storage abilities of the CeO2-ZrO2-Bi2O3 promoter, and allowed for the oxidation of Pt0 to Pt2+ with high activity. The highest activity was obtained for the Pt/CeO2-ZrO2-Bi2O3/ZrO2-E catalyst, which had the largest surface area and the highest oxygen release and storage abilities; phenol was completely removed after a reaction time of 10 h at 80°C under atmospheric pressure (0.1 MPa). [ABSTRACT FROM AUTHOR]

The effects of the Bi3+ introduction and the oxygen release and storage abilities on selective oxidation of glycerol into dihydroxyacetone (DHA) were demonstrated using Pt/CeO2-ZrO2-Bi2O3-SnO2/SBA-16 (SBA-16: Santa Barbara Amorphous No. 16) catalysts. By introducing Bi3+ or Sn4+/2+ ions into the CeO2-ZrO2 promoter, the oxygen release and storage abilities were enhanced, which led to increased glycerol conversion. The improvement in the DHA yield was affected by the introduction of Bi3+, which might accelerate selective oxidation of a secondary hydroxy group in glycerol caused by the geometric effect. The highest activity was obtained for Pt/Ce0.64Zr0.16Bi0.15Sn0.05O2−δ/SBA-16, which showed high oxygen release and storage abilities and a high number of Bi3+ ions, with the DHA yield increasing to 53% and high rates of glycerol conversion (74%) and DHA selectivity (72%) after reaction at a moderate temperature of 30 °C for 4 h in atmospheric air. [ABSTRACT FROM AUTHOR]

Cresol is among the phenolic compounds that are frequently found in industrial wastewater streams. Most notably, p-cresol has the highest toxicity and the highest permeability effect on skin of all the cresol isomers; hence, wastewater treatment for p-cresol removal is an important issue. This study was aimed at determining a method of removing p-cresol effectively under moderate conditions by catalytic oxidation. To this end, we synthesized a Pt/CeO2-ZrO2-SnO2/SBA-16 catalyst by supporting Pt as the activator and CeO2-ZrO2-SnO2 as the promoter on an SBA-16 support. As concerns the promoter, the introduction of ZrO2 and SnO2 improved its redox properties, and the superior redox properties of Ce0.68Zr0.17Sn0.15O2 facilitated generation of oxidized platinum ions (Pt2+) with a high phenolic compound oxidation capability compared to metallic platinum (Pt0). Among the catalysts prepared, Pt/CeO2-ZrO2-SnO2/SBA-16 with high Pt2+ content exhibited the highest catalytic activity for p-cresol oxidation, and p-cresol was completely removed under moderate reaction conditions of 80°C for 4 h under atmospheric pressure. [ABSTRACT FROM AUTHOR]

The effect of oxygen vacancies on catalytic activity for direct N2O decomposition was demonstrated in Zr1−xYxO2−δ solid solutions with a fluorite-related structure. The fluorite-type structure was formed as samples with a small amount of Y3+ (0.05 ≤ x ≤ 0.19) and a large amount of Y3+ (x ≥ 0.80), leading to the generation of a C-type structure derived from the fluorite-type structure by removing a quarter of the oxide anions. The oxygen vacancies worked as N2O adsorption sites and catalytic active sites, with the highest activity realized by the YO1.5 catalyst with a C-type structure, which contained the largest number of oxygen vacancies in the ZrO2-Y2O3 system. [ABSTRACT FROM AUTHOR]

A Pt/CeO2-ZrO2-Bi2O3/SBA-16 catalyst was prepared to realize highly selective oxidation of glycerol to produce dihydroxyacetone (DHA). An active oxygen supply from the CeO2-ZrO2-Bi2O3 promoter effectively oxidized glycerol to produce DHA under moderate conditions (i.e. at 30°C without applied pressure). After a 4 h catalytic reaction using the Pt/CeO2-ZrO2-Bi2O3/SBA-16 catalyst, the DHA yield and selectivity rose to 76% and 84%, respectively. [ABSTRACT FROM AUTHOR]

Red emitting phosphors of K3(Gd1−xEux)Si2O7 were synthesized by the conventional solid-state reaction method, and the crystal structure and the photoluminescent property were investigated. In this structure, Gd3+ ions occupy two sites in the GdO6 triangular prism and the GdO6 octahedron, and Eu3+ ions are predominantly introduced into the triangular prismatic Gd3+ sites from the results of the Rietveld analysis and the photoluminescence spectroscopy. Among the K3(Gd1−xEux)Si2O7 samples, the K3(Gd0.1Eu0.9)Si2O7 (x = 0.9) phosphor exhibited the highest emission intensity of 116% in comparison with the commercial (Y0.98Eu0.02)2O2S phosphor, caused by the effectively suppression of the concentration quenching in the structure. [ABSTRACT FROM AUTHOR]

PdO/CeO2-ZrO2-NiO/γ-Al2O3 catalysts were prepared for the combustion of methane at moderate temperatures. The introduction of a small amount of NiO within the cubic fluorite CeO2-ZrO2 structure as a promoter effectively enhanced the oxygen release and storage abilities of the catalysts, thereby achieving the complete oxidation of methane. The catalyst with the highest activity for methane combustion was 11.3 mass% PdO/20 mass% Ce0.64Zr0.16Ni0.2O1.9/γ-Al2O3, and efficient combustion was realized at a temperature as low as 300 °C. [ABSTRACT FROM AUTHOR]