Synergistic electric fields induced by unilateral doping modulation for enhanced organic pollutant degradation and sterilization

Abstract

Constructing a robust and large built-in electric field to boost photogenerated carrier separation efficiency has been a persistent challenge in photocatalysis. Herein, a carbon-rich carbon nitride (CCN/WO₃) S-scheme heterojunction was successfully developed, achieving effective charge separation through the synergistic interaction of the in-plane electric field within CCN and the interfacial electric field at the CCN/WO₃ interface. The robust in-plane electric field of CCN originated from the asymmetric structure induced by carbon substitution for nitrogen atoms in g-C₃N₄. Additionally, a strong interfacial electric field was established through combining CCN with WO₃ via a one-pot synthesis process. The CCN/WO₃ heterojunction demonstrated excellent performance in bacteria inactivation and organic pollutant degradation, with antibacterial activity against E. coli 20.4 times and 4.2 times higher than those of WO₃ and CN/WO₃, respectively, and a photocatalytic TC degradation rate constant 5.5 times higher than that of WO₃. Quantitative analysis revealed that the CCN/WO₃ heterojunction achieved 96.7 % selectivity for free radical generation, significantly higher than that of g-C₃N₄ (40.9 %), indicating a strong preference for activating O₂ through charge-carrier transfer pathways. This study demonstrates that leveraging the synergy between in-plane and interfacial electric fields offers a promising strategy to enhance charge separation in photocatalysts.