自己支持型カソードにおける拡散トリガー超均一分散コバルト単原子によるテトラサイクリン塩酸塩除去性能向上

While the generation of hydrogen peroxide using metal single-atom catalysts provides a promising pathway toward sustainable water purification, the preparation processes require further optimization to achieve full dispersion and efficient utilization of active sites. In this study, a facile lidded pyrolysis strategy is developed to fabricate a self-supporting N-doped carbon nanofiber electrode with atomically dispersed CoN₄ sites (Co@N-CNFs) for electro-Fenton (EF) degradation of tetracycline hydrochloride (TCH). The method involves electrospun polyacrylonitrile nanofibers embedded with patchy Co precursors, where lidded pyrolysis promotes the diffusion of Co vapor and N-containing radicals, yielding well-dispersed CoN₄ sites throughout the nanofibers. The resulting Co@N-CNFs electrode exhibits a 59-fold enhancement in H₂O₂ yield and an 11-fold increase in current efficiency compared to pristine N-doped carbon nanofibers (N-CNFs). Combined experiments with theoretical simulations reveal that single-atom Co significantly enhances charge transfer and stabilizes the key intermediate *OOH, thereby facilitating H₂O₂ generation. Benefiting from efficient H₂O₂ generation, the Co@N-CNFs EF system achieved 99.6% TCH degradation in 5 min-a performance that far exceeds that of the N-CNFs control (26.4%) and most recently reported systems-via synergistic radical (O₂^•- and •OH) and non-radical (¹O₂) pathways. Furthermore, the Co@N-CNFs EF system demonstrates low-toxicity degradation byproducts, exceptional stability, broad applicability, and low energy consumption for antibiotic removal even in real wastewater matrices, highlighting its practical potential. This study presents a simple lidded pyrolysis method to fabricate self-supporting EF cathodes with ultra-uniformly distributed single-atom metal sites and offers a promising approach toward sustainable water purification technologies.