TY - JOUR

T1 - Surface science approach to Pt/carbon model catalysts

T2 - XPS, STM and microreactor studies

AU - Motin, Abdul Md

AU - Haunold, Thomas

AU - Bukhtiyarov, Andrey V.

AU - Bera, Abhijit

AU - Rameshan, Christoph

AU - Rupprechter, Günther

N1 - Publisher Copyright: © 2018 The Authors

PY - 2018/1/31

Y1 - 2018/1/31

N2 - Pt nanoparticles supported on carbon are an important technological catalyst. A corresponding model catalyst was prepared by physical vapor deposition (PVD) of Pt on sputtered HOPG (highly oriented pyrolytic graphite). The carbon substrate before and after sputtering as well as the Pt/HOPG system before and after Pt deposition and annealing were examined by XPS and STM. This yielded information on the surface density of defects, which serve as nucleation centres for Pt, and on the size distribution (mean size/height) of the Pt nanoparticles. Two different model catalysts were prepared with mean sizes of 2.0 and 3.6 nm, both turned out to be stable upon UHV-annealing to 300 °C. After transfer into a UHV-compatible flow microreactor and subsequent cleaning in UHV and under mbar pressure, the catalytic activity of the Pt/HOPG model system for ethylene hydrogenation was examined under atmospheric pressure flow conditions. This enabled to determine temperature-dependent conversion rates, turnover frequencies (TOFs) and activation energies. The catalytic results obtained are in line with the characteristics of technological Pt/C, demonstrating the validity of the current surface science based model catalyst approach.

AB - Pt nanoparticles supported on carbon are an important technological catalyst. A corresponding model catalyst was prepared by physical vapor deposition (PVD) of Pt on sputtered HOPG (highly oriented pyrolytic graphite). The carbon substrate before and after sputtering as well as the Pt/HOPG system before and after Pt deposition and annealing were examined by XPS and STM. This yielded information on the surface density of defects, which serve as nucleation centres for Pt, and on the size distribution (mean size/height) of the Pt nanoparticles. Two different model catalysts were prepared with mean sizes of 2.0 and 3.6 nm, both turned out to be stable upon UHV-annealing to 300 °C. After transfer into a UHV-compatible flow microreactor and subsequent cleaning in UHV and under mbar pressure, the catalytic activity of the Pt/HOPG model system for ethylene hydrogenation was examined under atmospheric pressure flow conditions. This enabled to determine temperature-dependent conversion rates, turnover frequencies (TOFs) and activation energies. The catalytic results obtained are in line with the characteristics of technological Pt/C, demonstrating the validity of the current surface science based model catalyst approach.

KW - Carbon

KW - Ethylene

KW - Hydrogenation

KW - Microreactor

KW - Model catalysts

KW - Photoelectron spectroscopy

KW - Platinum

KW - Scanning tunneling microscopy

UR - http://www.scopus.com/inward/record.url?scp=85041385732&partnerID=8YFLogxK

U2 - 10.1016/j.apsusc.2018.01.148

DO - 10.1016/j.apsusc.2018.01.148

M3 - Article

AN - SCOPUS:85041385732

VL - 440.2018

SP - 680

EP - 687

JO - Applied surface science

JF - Applied surface science

SN - 0169-4332

IS - 15 May

ER -