A photocatalyst system is generally comprises a catalyst and cocatalyst to achieve light absorption, electron-hole separation, and surface reaction. It is a challenge to develop a single photocatalyst having all functions so as to lower the efficiency loss. Herein, the active GaN4 site is integrated into a polymeric carbon nitride (CN) photocatalyst (GCN), which displays an excellent H2 production rate of 9904 μmol h-1 g-1 . It is 162 and 3.3 times higher than that of CN with the absence (61 μmol h-1 g-1 ) and presence (2981 μmol h-1 g-1 ), respectively, of 1.0 wt % Pt. Under light irradiation the electron is injected and stored at the GaN4 site, where the LUMO locates. The HOMO distributes on the aromatic ring resulting in spatial charge separation. Transient photovoltage discloses the electron-storage capability of GCN. The negative GaN4 promotes proton adsorption in the excited state. The positive adsorption energy drives H2 desorption from GaN4 after passing the electron to the proton. This work opens up opportunities for exploring a novel catalyst for H2 production.
Keywords: carbon nitride; gallium; hydrogen; photocatalysis; structure elucidation.
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