Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Catalytic Etching of Platinoid Gauzes during the Oxidation of Ammonia by Air. Reconstruction of Surface of Platinoid Gauzes at 1133 K in Air, in Ammonia, and in an NH3 + O2 Reaction Medium. / Salanov, A. N.; Suprun, E. A.; Serkova, A. N. и др.
в: Kinetics and Catalysis, Том 59, № 1, 01.01.2018, стр. 83-98.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Catalytic Etching of Platinoid Gauzes during the Oxidation of Ammonia by Air. Reconstruction of Surface of Platinoid Gauzes at 1133 K in Air, in Ammonia, and in an NH3 + O2 Reaction Medium
AU - Salanov, A. N.
AU - Suprun, E. A.
AU - Serkova, A. N.
AU - Sidel’nikova, O. N.
AU - Sutormina, E. F.
AU - Isupova, L. A.
AU - Kalinkin, A. V.
AU - Parmon, V. N.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - The structure, morphology, and chemical composition of the surface and near-surface layers of platinoid wires of polycrystalline gauzes, containing Pt (81 wt %), Pd (15 wt %), Rh (3.5 wt %), and Ru (0.5 wt %) after treatment at 1133 K in various media—in air, in ammonia, and after NH3 oxidation in air—are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). A thin film is found on the surface of the initial gauze containing an oxide layer of Rh2O3 with a thickness of ~2 nm, on the surface of which an inhomogeneous graphite-like layer 10–50 nm thick is located. It is shown that the heat treatment of gauzes in air leads to the partial removal of the surface graphite-like film that forms the reticulated structure on the wire surface. The treatment of gauzes in an ammonia atmosphere leads to the complete removal of the graphite-like and oxide layers and to the growth of metal grains of ~10 μm. After the catalytic reaction of NH3 oxidation, a deep structural rearrangement of the surface layer of the wire takes place, as a result of which crystalline metal agglomerates of ~10 μm are formed. It is supposed that the reaction of NH3 molecules with oxygen atoms penetrated on the defects leads to the local increase of temperature, due to which the metal atoms emerge on the surface and form large crystalline agglomerates and pores in the region of the grain boundaries.
AB - The structure, morphology, and chemical composition of the surface and near-surface layers of platinoid wires of polycrystalline gauzes, containing Pt (81 wt %), Pd (15 wt %), Rh (3.5 wt %), and Ru (0.5 wt %) after treatment at 1133 K in various media—in air, in ammonia, and after NH3 oxidation in air—are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). A thin film is found on the surface of the initial gauze containing an oxide layer of Rh2O3 with a thickness of ~2 nm, on the surface of which an inhomogeneous graphite-like layer 10–50 nm thick is located. It is shown that the heat treatment of gauzes in air leads to the partial removal of the surface graphite-like film that forms the reticulated structure on the wire surface. The treatment of gauzes in an ammonia atmosphere leads to the complete removal of the graphite-like and oxide layers and to the growth of metal grains of ~10 μm. After the catalytic reaction of NH3 oxidation, a deep structural rearrangement of the surface layer of the wire takes place, as a result of which crystalline metal agglomerates of ~10 μm are formed. It is supposed that the reaction of NH3 molecules with oxygen atoms penetrated on the defects leads to the local increase of temperature, due to which the metal atoms emerge on the surface and form large crystalline agglomerates and pores in the region of the grain boundaries.
KW - ammonia catalytic oxidation
KW - catalytic etching
KW - platinoid gauzes
KW - scanning electron microscopy
KW - OXYGEN
KW - RAY PHOTOELECTRON-SPECTROSCOPY
KW - ADSORPTION
UR - http://www.scopus.com/inward/record.url?scp=85043294643&partnerID=8YFLogxK
U2 - 10.1134/S0023158418010093
DO - 10.1134/S0023158418010093
M3 - Article
AN - SCOPUS:85043294643
VL - 59
SP - 83
EP - 98
JO - Kinetics and Catalysis
JF - Kinetics and Catalysis
SN - 0023-1584
IS - 1
ER -
ID: 10354197