Pulsed Chronopotentiometry for Electrochemical CO ₂ Capture with Molecular Redox Mediators

Pulsed chronopotentiometry lowers cell voltage and energy input in aqueous Neutral Red-mediated electrochemical CO 2 capture. A pulse–reverse current (PRC) protocol provides a tunable operating mode that enables efficient control of polarization while preserving carbon capture performance. By adjustment of the pulse amplitude, duration, and duty cycle, PRC stabilizes the cell voltage and reduces energy consumption relative to direct-current (DC) operation at matched current density. Mechanistically, PRC regulates diffusion-layer dynamics by maintaining a thin, pulsation-controlled inner layer while periodically refreshing the outer layer, thereby suppressing concentration polarization and parasitic side reactions. Timing the on-period to Sand’s transition time preserves favorable near-surface Neutral Red/leuco-Neutral Red (NR/NRH 2 ) concentrations without increasing solution flow. These results demonstrate that PRC can match or outperform DC operation through parameter optimization and offers a scalable, energy-efficient strategy compatible with diverse electrochemical reactor architectures.