Enhanced photocatalytic performance of broken hollow tubular carbon nitride modified with nitrogen defects and hydroxyl groups for pollutant degradation and hydrogen production.

Graphite-phase carbon nitride (g-C 3 N 4) is widely recognized as a remarkable material for both the photocatalytic degradation of organic pollutants and photocatalytic water splitting for hydrogen production. In this study, we reported a method to obtain a broken hollow carbon nitride with nitrogen defects and hydroxyl groups, prepared from melamine and cyanuric acid through self-assembly. It demonstrated outstanding photocatalytic performance, achieving a 99.35% removal of Rhodamine B, 88.08% degradation of tetracycline hydrochloride, and a hydrogen production rate of 1671.12 μmol g−1 h−1, all of which are superior to the performance of bulk g-C 3 N 4. The superior redox performance was attributed to the significant increase in specific surface area and the synergistic effects of nitrogen defects and hydroxyl groups. These modifications effectively altered the built-in electric field, electronic structure, and redox potential of g-C 3 N 4. Experimental and theoretical analyses revealed that photogenerated electrons were enriched in nitrogen vacancies, while holes were captured by hydroxyl groups, resulting in the rapid transfer and separation of charge carriers. On this basis, possible synthesis pathways and photocatalytic mechanisms of the catalyst were proposed. This work provides a promising method for preparing modified carbon nitride with excellent photocatalytic performance. [Display omitted] • V N -CN-OH-45 shows a unique broken hollow tubular structure. • Nitrogen defects and hydroxyl groups synergistically enhance redox capacity. • DFT calculations indicate that defects facilitate charge separation and transfer. • Exceptional photocatalytic degradation of RhB and TCH. • Outstanding photocatalytic hydrogen production performance. [ABSTRACT FROM AUTHOR]