(64g) Competitive Transient Electrostatic Adsorption Mechanism for in Situ Regeneration of Poisoned Catalyst
Herein we report one new Competitive Transient Electrostatic Adsorption (CTEA) mechanism for energy-efficient and noninvasive in situ regeneration of poisoned catalyst. We utilize the Townsend discharge phenomena for Ar+ generation at a moderate DC voltage, and utilize CTEA of Ar+ for competition against chemisorbed poisoning species to regenerate the active sites. We verified effectiveness of this new concept by studying HCOOH decomposition as one model reaction and examining the effects of CTEA of Ar+ on the reaction properties. By applying a moderate DC voltage to create an electric field that generates Ar+ ions following the Townsend discharge mechanism, the deactivated Pt catalyst exhibited an immediate recovery of the activity. The extent of the catalyst activity recovery was discovered to increase proportionally to the measured Ar+ current, which was attributed to a larger number of Ar+ ions that facilitate the desorption of chemisorbed CO poisoning species to regenerate the active sites via the CTEA mechanism. DFT simulations together with Townsend discharge theory suggested that the electrostatic adsorption energy of Ar+ ions was dramatically bigger than the desorption energy of poisoning CO, which would force CO desorption to recover availability of the Pt active sites. The findings suggest CTEA mechanism offers a new, convenient and effective method to in situ regenerate poisoned catalyst materials, and shows a good potential to help reduce the operation cost associated with poisoned catalyst replacement in many reaction processes.