Enhanced Time-on-Stream Stability of Pt/CeO₂ Catalysts for the Water Gas Shift Reaction under Nonthermal Plasma Activation

Supported Pt catalysts are among the most promising materials for the water gas shift (WGS) reaction, offering efficient routes for hydrogen production and purification. However, their long-term stability remains a major challenge in conventional thermal catalytic processes due to CO poisoning and the accumulation of carbonaceous species that gradually block active sites and reduce catalytic activity. In this work, we demonstrate a nonthermal plasma (NTP)-assisted strategy to effectively mitigate these deactivation pathways and enhance catalyst stability. WGS reactions under both plasma and thermal conditions using the Pt/CeO₂ catalysts were examined. For the 2.0% Pt/CeO₂, under thermal conditions, the CO conversion dropped from 34.3% to 21.5% after 30 h, while under NTP conditions, the conversion remained stable at ∼34.1% throughout the entire test. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) combined with cyclic H₂O and CO switching experiments reveals that thermal deactivation is closely associated with the gradual buildup of carbonaceous species on the catalyst surface, which suppresses its interfacial activity. In contrast, the application of NTP facilitates the rapid turnover of these species, reducing accumulation on the surface. This helps to maintain a dynamic surface condition that preserves the active interfacial sites essential for WGS activity. Furthermore, kinetic analysis confirms that plasma activation effectively weakens CO inhibition by increasing the availability of active sites even at lower temperatures. These findings provide a deeper mechanistic understanding of plasma-assisted catalysis and highlight the potential of NTP technology to overcome stability limitations of Pt-based catalysts for efficient hydrogen production via the WGS reaction.