The mechanism at the initial stage of the room-temperature oxidation of coal

ABSTRACTThe differences of the room temperature oxidation behavior of ordered Ag/Si(111) and Au/Si(111) surfaces were studied by surface sensitive soft x-ray photoemission spectroscopy obtained with synchrotron radiation. Si surfaces covered with a monolayer of Ag or Au, once annealed to display a √3×√3 LEED pattern, were believed to be passivated against oxidation according to earlier reports. This work shows that these two surfaces oxidize but in a different way. Up to 104 L O2 exposures, the observed valence band of the Au/Si surface's valence band electron energy distribution curve is almost identical to that of the surface before oxygen exposure. But the corresponding Si 2p core level spectrum shows a small chemically shifted component indicating an initial stage of the formation of Si oxide. Thi3 chemically shifted signal becomes a strong peak at -3.7 eV below the clean Si position, characteristic of SiO2, after subsequent O2 exposures up to 1010 L. The Ag/Si system behaves in a similar fashion, but oxide growth saturates at 108 L, and the final oxides formed include a distribution of suboxides in addition to SiO2. Clearly, oxide formation is not prohibited by the presence of the ordered Au or Ag metal overlayer but delayed. Although the onset of oxidation is delayed compared to that for the clean Si surface, due to the metal-silicon bonding, the oxide formation is much faster once the surface starts to oxidize.

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Graphene oxide prepared by a room temperature oxidation using a green mechanochemical method.

Microscopy and Microanalysis ◽

10.1017/s1431927621002956 ◽

2021 ◽

Vol 27 (S1) ◽

pp. 726-728

Author(s):

G. Tarango-Rivero ◽

G. Herrera-Perez ◽

C. Carreño-Gallardo ◽

C.G. Garay-Reyes ◽

I. Estrada-Guel ◽

...

Keyword(s):

Graphene Oxide ◽

Room Temperature ◽

Mechanochemical Method ◽

Temperature Oxidation

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The influence of high-temperature oxidation on the phase distribution of metal substrate in duplex stainless steel

Oxidation of Metals ◽

10.1007/s11085-021-10068-1 ◽

2021 ◽

Author(s):

Minami Matsumoto ◽

Ken Kimura ◽

Natsuko Sugiura

Keyword(s):

Stainless Steels ◽

Room Temperature ◽

Phase Distribution ◽

High Strength ◽

Metal Substrate ◽

Temperature Oxidation ◽

Good Corrosion Resistance ◽

Mn Oxide ◽

Typical Type ◽

Compositional Changes

AbstractDuplex stainless steels (DSSs), which consist of ferrite and austenite phases, are widely used owing to their high strength and good corrosion resistance. However, the oxidation behavior of DSSs is extremely complicated because they have dual phases. In this study, changes in the scale and the metal substrate during oxidation were investigated. UNS S32101 (Fe-21.5%Cr–5%Mn–1.5%Ni–0.3%Mo–0.22%N), which is a typical type of DSS, was annealed at 1473 K for up to 36 ks in air. The microstructure of UNS S32101 consisted of austenite/ferrite phases, the ratio of which was 50:50 at room temperature. After oxidation, Cr, Mn-oxide formed predominantly. The metal substrate beneath the scale changed mostly to ferrite. In the same region, depletion of Mn and N concentrations resulted. The decrease in Mn was due to the formation of Cr, Mn-oxide. In addition, it was revealed that N content of the metal substrate decreased due to the formation of N2 gas along with the depletion of Mn. It was assumed that the decrease in Mn and N, which are austenite-stabilized elements, led to an increase in ferrite in the depletion area of Mn and N. From this result, it was expected that the compositional changes in the Mn/N depletion area were caused by the oxidation of steel.

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Room temperature oxidation of chromium and nickel implanted iron, and bulk alloys

Applications of Surface Science ◽

10.1016/0378-5963(83)90006-5 ◽

1983 ◽

Vol 15 (1-4) ◽

pp. 66-74 ◽

Cited By ~ 4

Author(s):

P.J. Osborne ◽

P.J.K. Paterson ◽

O. Spillecke

Keyword(s):

Room Temperature ◽

Temperature Oxidation ◽

Bulk Alloys

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Room-temperature oxidation of 2-aminobenzoyl- to 2-aminobenzoato-palladium(ii) complexes and of coordinated PPh3 by atmospheric oxygen; X-ray crystal structure of [(PPh3)2Pd(NH2C6H 4CO2-2)Pd{C(O)C6H 4NH2-2}(PPh3)]O3 SCF3

Chemical Communications ◽

10.1039/a701552f ◽

1997 ◽

pp. 959-960 ◽

Cited By ~ 12

Author(s):

José Vicente ◽

José-Antonio Abad ◽

Andrew D. Frankland ◽

M.-Carmen Ramírez de Arellano

Keyword(s):

Crystal Structure ◽

Room Temperature ◽

Atmospheric Oxygen ◽

Temperature Oxidation ◽

X Ray

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STRUCTURAL AND ELECTRONIC PROPERTIES OF THE Li/Si(001) SURFACE

Surface Review and Letters ◽

10.1142/s0218625x96002497 ◽

1996 ◽

Vol 03 (03) ◽

pp. 1487-1494

Author(s):

J.W. CHUNG

Keyword(s):

Electronic Properties ◽

Binding Sites ◽

Room Temperature ◽

Structural Models ◽

Metallic Phase ◽

Surface Band ◽

Ordered Structures ◽

Initial Stage ◽

Structural And Electronic Properties ◽

Characteristic Features

Atomic arrangements and electronic properties of the Li-adsorbed Si(001) surface are briefly reviewed. Characteristic features of a series of ordered structures with increasing Li coverage at room temperature are described. Structural models invoking a dimer flipping mechanism are discussed for the first two ordered structures, (2×2)-Li and (2×1)-Li, which are proposed as reconstructions of the silicon substrate. It is shown that the metallic phase found at an initial stage of adsorption is a result of substrate metallization, which explains the presence of an intraband surface plasmon. The features of the surface band structures for the first two ordered structures are discussed in terms of variation of the binding sites with coverage. All the unique features of the Li/Si(001) surface essentially exhibit the size effects of Li.

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Room temperature oxidation rate constants of ultra- thin (discontinuous) molybdenum films

Thin Solid Films ◽

10.1016/0040-6090(76)90630-1 ◽

1976 ◽

Vol 39 ◽

pp. 125-131 ◽

Cited By ~ 16

Author(s):

S.M. Deshpande

Keyword(s):

Rate Constants ◽

Oxidation Rate ◽

Room Temperature ◽

Temperature Oxidation

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Hollow structured CoSn(OH)6-supported Pt for effective room-temperature oxidation of gaseous formaldehyde

Functional Materials Letters ◽

10.1142/s1793604716420091 ◽

2016 ◽

Vol 09 (06) ◽

pp. 1642009 ◽

Cited By ~ 4

Author(s):

Jing Zhou ◽

Yong Zhao ◽

Lifan Qin ◽

Chen Zeng ◽

Wei Xiao

Keyword(s):

Electron Microscopy ◽

Catalytic Activity ◽

Room Temperature ◽

Synergetic Effect ◽

Hollow Structure ◽

Pt Nanoparticles ◽

Hydroxyl Groups ◽

High Catalytic Activity ◽

Temperature Oxidation ◽

X Ray

Uniform CoSn(OH)6 hollow nanoboxes and the derivative with Pt loading (Pt/CoSn(OH)6) were herein synthesized and characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). SEM and TEM analyses showed that CoSn(OH)6 possessed mesoporous hollow structure and Pt nanoparticles with size of 2–8[Formula: see text]nm were uniformly dispersed on the surface of CoSn(OH)6 nanoboxes. The performances of the catalysts for the formaldehyde (HCHO) removal at room temperature were evaluated. These Pt/CoSn(OH)6 catalysts exhibited a remarkable catalytic activity as well as stability for room-temperature oxidative decomposition of gaseous HCHO, while the corresponding CoSn(OH)6 only showed adsorption. The synergetic effect between the highly dispersed Pt nanoparticles and the CoSn(OH)6 nanoboxes with mesoporous hollow structure, a large surface area and abundant surface hydroxyl groups is considered to be the main reason for the observed high catalytic activity of Pt/CoSn(OH)6.

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