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CO Oxidation on Planar Au/TiO 2 Model Catalysts under Realistic Conditions: A Combined Kinetic and IR Study
Author(s) -
Diemant Thomas,
Bansmann Joachim
Publication year - 2021
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202000960
Subject(s) - catalysis , kinetic energy , activation energy , chemistry , redox , planar , order of reaction , kinetics , reaction mechanism , inorganic chemistry , analytical chemistry (journal) , chemical engineering , materials science , reaction rate constant , organic chemistry , physics , computer graphics (images) , quantum mechanics , computer science , engineering
The oxidation of CO on planar Au/TiO 2 model catalysts was investigated under pressure and temperature conditions similar to those for experiments with more realistic Au/TiO 2 powder catalysts. The effects of a change of temperature, pressure, and gold coverage on the CO oxidation activity were studied. Additionally, the reasons for the deactivation of the catalysts were examined in long‐term experiments. From kinetic measurements, the activation energy and the reaction order for the CO oxidation reaction were derived and a close correspondence with results of powder catalysts was found, although the overall turnover frequency (TOF) measured in our experiments was around one order of magnitude lower compared to results of powder catalysts under similar conditions. Furthermore, long‐term experiments at 80 °C showed a decrease of the activity of the model catalysts after some hours. Simultaneous in‐situ IR experiments revealed a decrease of the signal intensity of the CO vibration band, while the tendency for the build‐up of side products (e. g. carbonates, carboxylates) of the CO oxidation reaction on the surface of the planar model catalysts was rather low.