• Strong metal-support interaction exists on Pt/Fe3O4 catalysts. • Pt metal particles facilitate the formation of oxygen vacancies on Fe3O4. • Fe3O4 supports enhance the strength of CO adsorption on Pt metal particles.
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The self-inhibition behavior due to CO poisoning on Pt metal particles strongly impairs the performance of CO oxidation. It is an effective method to use reducible metal oxides for supporting Pt metal particles to avoid self-inhibition and to improve catalytic performance. In this work, we used
in situ reductions of chloroplatinic acid on commercial Fe
3O
4 powder to prepare heterogeneous-structured Pt/Fe
3O
4 catalysts in the solution of ethylene glycol. The heterogeneous Pt/Fe
3O
4 catalysts achieved a better catalytic performance of CO oxidation compared with the Fe
3O
4 powder. The temperatures of 50% and 90% CO conversion were achieved above 260°C and 290°C at Pt/Fe
3O
4, respectively. However, they are accomplished on Fe
3O
4 at temperatures higher than 310°C. XRD, XPS, and H
2-TPR results confirmed that the metallic Pt atoms have a strong synergistic interaction with the Fe
3O
4 supports. TGA results and transient DRIFTS results proved that the Pt metal particles facilitate the release of lattice oxygen and the formation of oxygen vacancies on Fe
3O
4. The combined results of O
2-TPD and DRIFTS indicated that the activation step of oxygen molecules at surface oxygen vacancies could potentially be the rate-determining step of the catalytic CO oxidation at Pt/Fe
3O
4 catalysts. The reaction pathway involves a Pt-assisted Mars-van Krevelen (MvK) mechanism.
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