Pulsed Oxidation-Driven Catalyst Regeneration Enabling Durable CO-Tolerant Low-Temperature Electrochemical Hydrogen Pumps

Abstract

Efficient hydrogen recovery from impure gas streams remains a key challenge for a scalable hydrogen infrastructure. While low-temperature electrochemical hydrogen pumps (LT-EHPs) offer simultaneous hydrogen purification and compression, their performance is severely compromised in the presence of carbon monoxide (CO) due to strong CO adsorption on Pt active sites, leading to pronounced catalyst poisoning and reduced hydrogen throughput. Existing approaches, such as high-temperature operation and air bleeding, are either energy- or resource-intensive or suffer from side reactions and undesirable byproducts. Thus, developing efficient, durable, and practical strategies for CO mitigation remains a major barrier to the wide deployment of LT-EHPs for hydrogen purification. This work investigates an LT-EHP fed with 1% CO in H₂/N₂, evaluating separation and energy efficiencies (SE/EE). To sustain performance under prolonged CO exposure, we systematically investigated advanced pulse oxidation protocols for CO mitigation, focusing on dynamic voltage-triggered pulsing as a promising solution. A cutoff voltage was used to trigger dynamic pulse oxidation, applying pulses only when cell voltage exceeded a set cutoff (e.g., 0.45 V), unlike fixed-interval pulsing, which delivers pulses at regular intervals regardless of cell voltage and can result in excessive overpotentials and increased catalyst corrosion. Dynamic pulsing ensures targeted catalyst regeneration while minimizing unnecessary stress. This approach delivered more than 10% higher SE and over 15% higher EE compared to the no-pulse scenario. Additionally, it surpassed fixed-interval pulsing by over 8% in SE and 10% in EE under identical impurity conditions. Five days of stable operation confirmed the promise of dynamic pulse oxidation as the most effective strategy for impurity-resilient hydrogen pumping in clean energy systems. A stable five-day operation demonstrated the viability of pulse oxidation for impurity-resilient hydrogen pumping in clean energy systems.