Disordered nitrogen-defect-rich porous carbon nitride photocatalyst for highly efficient H2 evolution under visible-light irradiation

Precursor types play crucial factors for synthesizing high-efficiency graphitic carbon nitrides (GCNs). Herein, biuret was employed as a new precursor to prepare a disordered nitrogen-defect-rich porous GCN (BCN). The crystallinity, structure and performance properties for BCN were explored by making systematic comparisons with other commonly available GCNs which were derived from conventional precursors under the identical conditions. Biuret could be the optimal choice for the preparation of highperformance GCN according to the reports so far. BCN not only possessed long-range atomic disordered structure, but also contained numerous nitrogen defects embedded into the in-planes of the disordered GCN networks, leading to extended visible-light absorption (absorption edge at 525 nm), improved separation of photoexcited charge carriers, and rich available reactive sites. The large surface area and high porosity of BCN also provided plenty of reactive sites. Consequently, ultrahigh photocatalytic H-2 production and excellent O-2 production performance were achieved for BCN, the AQY for H-2 production achieved 45.5% at 420 nm, which was one of the highest values for GCN-based photocatalysts. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The optimal choice for preparing high-performance GCN appears to be biuret, as BCN exhibited a long-range atomic disordered structure with numerous nitrogen defects embedded and extended visible-light absorption, improved charge carrier separation, and rich available reactive sites. This resulted in ultrahigh photocatalytic H-2 production and excellent O-2 production performance, with a high AQY of 45.5% at 420 nm, making it one of the top performers among GCN-based photocatalysts.