Research output: Contribution to journal › Article › peer-review
An XPS and STM Study of Oxidized Platinum Particles Formed by the Interaction between Pt/HOPG with NO2. / Smirnov, M. Yu; Vovk, E. I.; Nartova, A. V. et al.
In: Kinetics and Catalysis, Vol. 59, No. 5, 01.09.2018, p. 653-662.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - An XPS and STM Study of Oxidized Platinum Particles Formed by the Interaction between Pt/HOPG with NO2
AU - Smirnov, M. Yu
AU - Vovk, E. I.
AU - Nartova, A. V.
AU - Kalinkin, A. V.
AU - Bukhtiyarov, V. I.
N1 - Publisher Copyright: © 2018, Pleiades Publishing, Ltd.
PY - 2018/9/1
Y1 - 2018/9/1
N2 - X-ray photoelectron spectroscopy (XPS) (with AlKα and AgLα radiations) and scanning tunneling microscopy (STM) were used to study the interaction of two model samples prepared by vacuum evaporation of platinum on highly oriented pyrolytic graphite (HOPG) with NO2 at room temperature. According to STM data, platinum evaporation on the graphite surface produced particles of a flattened shape. In the Pt/HOPGS1 sample with a lower concentration of platinum, the average diameter of particles d and the height-to-diameter ratio h/d were 2.8 nm and 0.29, respectively. In the Pt/HOPG-S2 sample with a higher concentration of platinum, the average values of d and h/d were 5.1 nm and 0.32. When the samples interacted with NO2 (P ≈ 3 × 10–6 mbar), the particles of metallic platinum completely converted to the particles of PtO2· Upon oxidation, the shape of larger platinum particles in the Pt/HOPG-S2 sample did not change, although for the dispersed particles in the Pt/HOPG-S1 samples under these conditions, the h/d ratio increases. The reduction of oxide to metal particles on heating the Pt/HOPG-S1 sample in vacuum at 460°С is accompanied by an increase in the size of particles. Their shape became more round compared to the initial one. It was found that X-ray radiation affects the state of platinum in the oxidized sample by reducing the surface layer of PtO2 to PtO.
AB - X-ray photoelectron spectroscopy (XPS) (with AlKα and AgLα radiations) and scanning tunneling microscopy (STM) were used to study the interaction of two model samples prepared by vacuum evaporation of platinum on highly oriented pyrolytic graphite (HOPG) with NO2 at room temperature. According to STM data, platinum evaporation on the graphite surface produced particles of a flattened shape. In the Pt/HOPGS1 sample with a lower concentration of platinum, the average diameter of particles d and the height-to-diameter ratio h/d were 2.8 nm and 0.29, respectively. In the Pt/HOPG-S2 sample with a higher concentration of platinum, the average values of d and h/d were 5.1 nm and 0.32. When the samples interacted with NO2 (P ≈ 3 × 10–6 mbar), the particles of metallic platinum completely converted to the particles of PtO2· Upon oxidation, the shape of larger platinum particles in the Pt/HOPG-S2 sample did not change, although for the dispersed particles in the Pt/HOPG-S1 samples under these conditions, the h/d ratio increases. The reduction of oxide to metal particles on heating the Pt/HOPG-S1 sample in vacuum at 460°С is accompanied by an increase in the size of particles. Their shape became more round compared to the initial one. It was found that X-ray radiation affects the state of platinum in the oxidized sample by reducing the surface layer of PtO2 to PtO.
KW - highly oriented pyrolytic graphite
KW - NO
KW - platinum
KW - scanning tunneling microscopy (STM)
KW - X-ray photoelectron spectroscopy (XPS)
KW - THERMAL-STABILITY
KW - SUPPORTED CATALYSTS
KW - SIZE
KW - CO OXIDATION
KW - NO2
KW - NANOPARTICLES
KW - RAY PHOTOELECTRON-SPECTROSCOPY
KW - X-RAY
KW - SURFACE
KW - IN-SITU
KW - NITROGEN-DIOXIDE
UR - http://www.scopus.com/inward/record.url?scp=85053858450&partnerID=8YFLogxK
U2 - 10.1134/S0023158418050129
DO - 10.1134/S0023158418050129
M3 - Article
AN - SCOPUS:85053858450
VL - 59
SP - 653
EP - 662
JO - Kinetics and Catalysis
JF - Kinetics and Catalysis
SN - 0023-1584
IS - 5
ER -
ID: 16702728