Influence of Hydrogen and Oxygen Impurities on Platinum-Catalyzed Acetylene Hydrochlorination
Ayesha A Alkhoori1, Andrea Ruiz-Ferrando1, Vera Giulimondi1
1Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
Abstract:
Platinum (Pt) nanostructuring is a powerful strategy for tuning adsorption properties and reactivity in vinyl chloride monomer (VCM) synthesis. To ensure relevance beyond ideal conditions, catalyst performance must be evaluated under more realistic acetylene (C2H2) feeds containing unavoidable impurities such as oxygen (O2) and hydrogen (H2), which can impair the performance through competitive adsorption and active site modification. Herein, we study the behavior of Pt single atom (SA) under multicomponent feeds containing H2 and O2. Pt SA maintains high activity in the presence of H2, showing full VCM selectivity and no hydrogenation products, owing to their high affinity for HCl. In contrast, cofeeding O2 leads to a drop in VCM yield of up to 80%, indicating pronounced inhibition. This is proven by O2-desorption profiles and DFT simulations, which show increasingly favorable O2 adsorption upon dechlorination, resulting in oxidative site blocking. These results highlight the importance of maintaining the atomic dispersion of Pt for sustaining selective and robust reactivity under realistic conditions.
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