A facile synthesis of high-crystalline g-C3N4 nanosheets with closed self-assembly strategy for enhanced photocatalytic H2 evolution

Highlights: • The high-crystalline g-C3N4 nanosheet was synthesized with a facile closed self-assembly strategy. • The synthesized high-crystalline g-C3N4 has a wider band gap and a greater specific surface area than bulk carbon nitride. • The photocatalytic activity of the high-crystalline g-C3N4 nanosheet was exhibited 6 times in hydrogen production than that of bulk g-C3N4. -- Abstract: High crystallinity and few layers of carbon nitride (g-C₃N₄) can increase carrier migration rate and photocatalytic activity sites, which is beneficial to enhance the photocatalytic activity of carbon nitride. Herein, we synthesized high-crystalline g-C₃N₄ nanosheets with a facile method of closed self-assembly strategy without adding any template and other auxiliary materials. XRD and HRTEM exhibited that high-crystalline g-C₃N₄ was synthesized, the average thickness and specific surface area of the high-crystalline g-C₃N₄ nanosheets were 4.8 nm and 95.10 m²g⁻¹, respectively. Due to the efficient separation of photogenerated carriers and low charge-transfer resistance, high-crystalline g-C₃N₄ nanosheets demonstrated much better photocatalytic activity (8116 μmol h⁻¹ g⁻¹) than that of bulk g-C₃N₄, exhibiting 6-folds of enhancement on hydrogen evolution. Beneficial from its good photocatalytic activity and convenient fabrication method, it is anticipated that high-crystalline g-C₃N₄ nanosheets will find more applications in the renewable energy fields.