Segmented Structure Design of Carbon Ring In‐Plane Embedded in g‐C3N4 Nanotubes for Ultra‐High Hydrogen Production

Abstract The photocatalytic water splitting capability of metal‐free graphitic carbon nitride (g‐C 3 N 4 ) photocatalyst is determined by its microstructure and photoexcited electrons transfer. Herein, a segmented structure was developed, consisting of alternant g‐C 3 N 4 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 150 nm 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 π‐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 μmol h −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 420 nm. This work may provide a pathway for simultaneous morphology regulation and in‐plane modification of high‐performance photocatalysts.