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The synergistic effect of sodium and oxygen expands π-conjugated aromatic rings and distortion of the heptazine skeleton, enhancing the intrinsic π→π* electron transition and the effective n→π* electron transition. [Display omitted] • A sodium and oxygen co-doped g-C 3 N 4 (NaOCN) is prepared by facile microwave synthesis, in which Na as a charge transport channel promotes the separation efficiency of photogenerated carriers. • The as-prepared NaOCN exhibits the NIR absorption extended to 1400 nm and the apparent quantum yield (AQY) can keep 26.9% at 420 nm and still maintain 7.2 % at 600 nm, which shows strong NIR response range. • The intrinsic π → π* electron transition and active the n → π* electron transition generated by the synergistic effect of Na and O atoms are the main factor to promote the NIR response of NaOCN. Efficient utilization of near-infrared light (NIR) is critical to optimize the performance of photocatalysts. Herein, an ultrafast process is employed to co-condensation of melamine and NaCl by microwave-assist heating. The fabricated sodium and oxygen co-doped g-C 3 N 4 (NaOCN) shows extended π-conjugated aromatic rings and distortion of the heptazine skeleton, which can enhance the intrinsic π → π* electron transition and active the n → π* electron transition. The robust n → π* excitation of NaOCN leads to a narrowed bandgap of 2.73 eV with the NIR absorption extending to 1400 nm. The apparent quantum yield (AQY) for NaOCN can still keep 7.2 % at 600 nm. This work provides a promising way for the application of NIR-based carbon nitride in photocatalytic H 2 O 2 production. [ABSTRACT FROM AUTHOR]

• A photocatalyst was constructed by combining direct Z-scheme and isotype heterojunction. • A ternary Δ(Z + H)-scheme g-C 3 N 4 /g-C 3 N 4 /BiOBr photocatalyst is prepared by an effective combination of thermal decomposition and solvothermal method. • Solar light utilization can be enhanced in ternary Δ(Z + H)-scheme g-C 3 N 4 /g-C 3 N 4 /BiOBr. • The composites is wide application in the degradation of organic pollutants (RhB, FITC and TC), which potential to be applied as a photocatalyst for wastewater treatment. A novel ternary direct Z-scheme + isotype heterojunction, Δ(Z + H)-scheme photocatalyst CN-TU/BiOBr was fabricated by an effective combination of thermal decomposition and solvothermal method. The samples of g-C 3 N 4 prepared using urea, thiourea and thiourea-urea complexes as precursors were named CN-U, CN-T and CN-TU, respectively. In addition, CN-M was prepared by physically mixing CN-U and CN-T. The structure, morphology, optical and electronic properties of the prepared samples were characterized by XRD, FTIR spectra, SEM-EDS, BET, XPS and DRS. The photocatalytic activities of the synthesized samples were estimated by the degradation of Rhodamine B (RhB), Fluorescein isothiocyanate (FITC) and antibiotic tetracycline hydrochloride (TC) in the presence of visible light. Compared with other as-prepared samples, the ternary 1%CN-TU/BiOBr photocatalyst exhibited an excellent activity, which is attributed to the construction of the ternary Δ(Z + H)-scheme not only benefit to maintain outstanding redox capability of the electrons, but also facilitates the separation of photo-generated carrier. Furthermore, the stability of the sample is tested by cyclic experiments. This work will provided a new insight into optimizing the structure and designing similar Z-scheme photocatalytic system. [ABSTRACT FROM AUTHOR]