Segmented structure design of carbon ring in‐plane embedded in g‐C3N4 nanotubes for ultra‐high hydrogen production

The photocatalytic water splitting capability of metal-free graphitic carbon nitride (g-C3N4) photocatalyst is determined by its microstructure and photoexcited electrons transfer. Herein, a segmented structure was developed, consisting of alternant g-C3N4 nanotubes and graphitic carbon rings (denoted as C-r-CN-NT). The C-r-CN-NT showed ordered structure and ultralong length/diameter ratio of 150nm in diameter and a few microns in lengths, which promoted electron transport kinetics and elongated photocarrier diffusion length and lifetime. Meanwhile, the local in-plane pi -conjugation was formed and extended in C-r-CN-NT, which could improve charge carrier density and prohibit electron-hole recombination. Accordingly, the average hydrogen evolution rate of C-r-CN-NT reached 9245 mu molh(-1)g(-1), which was 61.6 times that of pristine CN, and the remarkable apparent quantum efficiency (AQE) of C-r-CN-NT reached up to 12.86% at 420nm. This work may provide a pathway for simultaneous morphology regulation and in-plane modification of high-performance photocatalysts.