Constructing a Ta3N5/Tubular Graphitic Carbon Nitride Van Der Waals Heterojunction for Enhanced Photocatalytic Hydrogen Production

Constructing a heterojunction is considered one of the most effective strategies for enhancing photocatalytic activity. Herein, we employ Ta3N5 and tubular graphitic carbon nitride (TCN) to construct a Ta3N5/TCN van der Waals heterojunction via electrostatic self-assembly for enhanced photocatalytic H2 production. SEM and TEM results show that Ta3N5 particles (~300 nm in size) are successfully anchored onto the surface of TCN. The light absorption capability of the Ta3N5/TCN heterojunction is between those of Ta3N5 and TCN. The strong interaction between Ta3N5 and TCN with different energy structures (Fermi levels) by van der Waals force renders the formation of an interfacial electric field to drive the separation and transfer of photogenerated charge carriers in the Ta3N5/TCN heterojunction, as evidenced by the photoluminescence (PL) and photoelectrochemical (PEC) characterization results. Consequently, the optimal Ta3N5/TCN heterojunction exhibits a remarkable H2 production rate of 12.73 mmol g−1 h−1 under visible light irradiation, which is 3.3 and 16.8 times those of TCN and Ta3N5, respectively. Meanwhile, the cyclic experiment demonstrates excellent stability of the Ta3N5/TCN heterojunction upon photocatalytic reaction. Notably, the photocatalytic performance of 15-TaN/TCN outperforms the most previously reported CN-based and Ta3N5-based heterojunctions for H2 production. This work provides a new avenue for the rational design of CN-based van der Waals heterojunction photocatalysts with enhanced photocatalytic activity.