Structure defined 2D Mo2C/2Dg-C3N4 Van der Waals heterojunction: Oriented charge flow in-plane and separation within the interface to collectively promote photocatalytic degradation of pharmaceutical and personal care products

Pharmaceuticals and personal care products (PPCPs) are a large class of emerging contaminants. Here, we develop a 2D/2D Mo2C/g-C3N4 Van der Waals (VDW) heterojunction photocatalyst for typical PPCPs degradation. The 2D Mo2C shows unique electronic transport properties and allows the integration with other 2D materials for fabricating intriguing 2D interface. The Mo2C strongly coordinates with g-C3N4 to endow the ordered in-plane electron migration in g-C3N4 nanosheets and the VDW forces induce the electrons transfer within interlayers, building an internal electric field and stimulating the photogenerated charge kinetics. In addition, Mo2C can ameliorate the light absorption capacity and trap electrons to elongate the lifetimes of charge carriers. This synergy between VDW heterojunction and 2D structure engineering contributes to the superior photocatalytic activity for tetracycline degradation. Advanced characterizations, charge density based on density function theory calculations and the absence of charge transfer between layers confirm the VDW interactions between the individual components. This work provides a highly efficient and green strategy for typical PPCPs removal, and sheds lights on the construction of 2D/2D VDW heterojunction photocatalysts.