Single-atom Pt anchored thiophene ring doped carbon nitride nanosheets for enhanced visible-light photocatalytic H₂ evolution and ciprofloxacin degradation

A small amount of cocatalysts often play a crucial role in polymerization semiconductor photocatalytic reactions, and precious metals, like Pt, remain irreplaceable as cocatalysts in most applications due to their excellent properties. Meanwhile, maximizing the atomic utilization of cocatalysts and enhancing the host-guest interactions are important routes to enhance photocatalytic efficiency. Single Pt atoms anchored thiophene ring-doped carbon nitride nanosheets (Pt_x-CNA) by a facile incipient wetness impregnation were successfully synthesized in this work. Single-atom Pt are uniformly embedded in CNA nanosheets through Pt–N coordination bonds. Coordinated electron-rich thiophene ring-doping and single-atom Pt modifications promote wider visible light response, enhanced charge response, and fast transport capability in Pt-CNA materials. Pt_1.0-CNA sample displays the most outstanding photocatalytic H₂ evolution rate (360.0 μmol h⁻¹), which is nearly 5 times that of Pt_1.0-CN (70.5 μmol h⁻¹). Excellent photocatalytic degradation performance of ciprofloxacin is also achieved and the degradation rate constant of Pt_1.0-CNA is 1.8 times that of CNA. Molecular modifications and single-atom cocatalytic together significantly improve the photocatalytic efficiency of polymer semiconductors.