ZnSe decorated g-C3N4 nanosheets toward efficient methylene blue and tetracycline hydrochloride removal

Developing scalable photocatalysts with engineered charge-transfer pathways is essential for advancing sustainable pollutant remediation technologies. Z-scheme ZnSe/g-C 3 N 4 heterojunctions are constructed through an interfacial in-situ growth strategy at a polar/non-polar solvent boundary, introducing a previously unexplored route for forming highly uniform and strongly coupled semiconductor interfaces. This solvent-interface directed synthesis enables homogeneous assembly of small ZnSe nanoparticles on ultrathin g-C 3 N 4 nanosheets, creating intimate junctions that fundamentally enhance charge separation and redox capability. Free radical capture experiments verify a Z-scheme charge transfer pathway, demonstrating that the engineered interface effectively preserves high energy electrons and holes essential for robust photocatalytic reactions. The optimized heterostructure achieves complete degradation of methylene blue (20 mg L -1 ) within 10 min and 76% removal of tetracycline hydrochloride (40 mg L -1 ) within 60 min, with high rate constants of 0.355 and 0.021 min -1 , respectively. It retains over 98% of its initial activity after four cycles, underscoring excellent operational durability. The exceptional performance arises from the novel interfacial growth mechanism, which yields well-developed Z-scheme junctions and leverages the more positive conduction band of ZnSe to boost redox strength. This work establishes a new solvent-interface engineering paradigm for designing efficient, stable, and scalable photocatalysts for sustainable pollutant remediation.