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

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/WO 3 ) 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/WO 3 interface. The robust in-plane electric field of CCN originated from the asymmetric structure induced by carbon substitution for nitrogen atoms in g-C 3 N 4 . Additionally, a strong interfacial electric field was established through combining CCN with WO 3 via a one-pot synthesis process. The CCN/WO 3 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 WO 3 and CN/WO 3 , respectively, and a photocatalytic TC degradation rate constant 5.5 times higher than that of WO 3 . Quantitative analysis revealed that the CCN/WO 3 heterojunction achieved 96.7 % selectivity for free radical generation, significantly higher than that of g-C 3 N 4 (40.9 %), indicating a strong preference for activating O 2 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.