Efficient degradation of organic pollutants by enhanced interfacial internal electric field induced via various crystallinity carbon nitride homojunction

Herein, a homojunction carbon nitride photocatalyst integrated with three crystallization levels (Tri-crystallinity) is developed to enhance the degradation activity of organic pollutants. The increase in crystallinity induces the Fermi level and band position to decrease. This difference constructs an internal electric field (IEF) at the interface with a lower to higher crystallinity direction. The multiple contact interfaces in Tri-crystallinity reinforce the interfacial IEF twice compared to a conventional single-interface. The interfacial IEF improves charge separation and transfer, and the degradation of antibiotics by Tri-crystallinity carbon nitride is at least 20 times greater than primary carbon nitride. Further, the Tri-crystallinity carbon nitride loading on a nonwoven fabric in a continuous-flow reactor achieves 91.0% purification of the organic wastewater at a flow rate of 14.2 L h⁻¹ m⁻² from 11:00 a.m. to 3:00 p.m. This work provides a strategy for engineering interfacial IEF of future efficient photocatalysts.