Abundant hydroxyl groups decorated on nitrogen vacancies-embedded g-C3N4 with efficient photocatalytic hydrogen evolution performance

Regulation of the properties of photocatalytic materials that are targeted at maximizing their superiorities in photocatalytic H2 evolution are essential for full utilization of solar energy but still face enormous challenges. In this work, engineering of hydroxyl and nitrogen vacancies on graphitic carbon nitride (g-C3N4) was fabricated via a flexible calcination–hydrothermal method. The characterization indicated that loss of N atoms at N2C resulted in the exposure of lone-pair electrons on the adjacent C atoms, thus stimulating anchoring of abundant hydroxyl on g-C3N4. Meanwhile, hydroxyl and N vacancies could capture the holes and electrons separately, which mitigated the recombination of photogenerated carriers. Furthermore, the improvement in hydrophilicity triggered by hydroxyl and the decreased conduction band caused by the N vacancies were critical for boosting the photocatalytic activity. As a result, an average H2 evolution rate of 232.75 μmol h−1 g−1 was achieved, which was about 4.2 times higher than that of pristine g-C3N4. This research lays good foundations and provides new insights into engineering highly efficient g-C3N4 with modified surface and electronic structures.