Constructing supramolecular self-assembled porous g-C3N4 nanosheets containing thiophene-groups for excellent photocatalytic performance under visible light

[Display omitted] •Porous g-C3N4 nanosheets prepared via supramolecular self-assembled method.•Porous g-C3N4 nanosheets with thiophene-group have superior photocatalytic activity.•Treatment of g-C3N4 catalyst with thiophene improves photoelectron transfer rate.•The composite catalyst displays nearly undiminished activity after 5 cycles. Enhancing catalytic visible light capture and light utilization efficiency represent an important objective in graphitic carbon nitride (g-C3N4) research. Herein, a novel sulfur-containing thiophene-grafted g-C3N4 porous nanosheets (CM-CN-Th A) prepared via co-thermal polycondensation of supramolecular self-assembled precursors (CM) and 3-thiophenecarboxylic acid (Th A) is reported. The introduction of thiophene groups improved the optical properties of the synthesized catalyst in the visible range, enhanced charge carrier separation, and suppressed e-/h+ pair complexation compared to pristine g-C3N4. Various analytical techniques were employed to characterize the structure, morphology, and electrical and optical features of the synthesized catalysts. In the removal of rhodamine B (Rh B) from aqueous media, CM-CN-Th A displayed favorable photocatalytic activity (rate constant k of 0.0360 min−1) under visible light illumination (λ > 420 nm), with photocatalytic removal effieciency of 89.22%, mineralization efficiency of 45.34%; this value was maintained after five cycles. The catalyst also delivers superior photocatalytic activity for methyl orange (MO), methylene blue (MB), and crystalline violet (CV) degradation, demonstrating wide applicability for dye wastewater treatment. In addition, a possible photocatalytic mechanism of CM-CN-Th A is proposed by analyzing the experimental results of active species capture. This work offers a novel approach for the photodegradation of dye wastewater.