Enhanced photocatalytic activity of direct Z -scheme Bi 2 O 3 /g-C 3 N 4 composites via facile one-step fabrication

Coupling oxidation type semiconductors is a feasible strategy to improve the photocatalytic activity of reduction type g-C 3 N 4 photocatalysts. In this work, Bi 2 O 3 was used as an oxidation type semiconductor to construct direct Z -scheme Bi 2 O 3 /g-C 3 N 4 photocatalysts by a one-step calcination method. The obtained Bi 2 O 3 /g-C 3 N 4 composites exhibited excellent photocatalytic activity and stability toward methylene blue degradation under visible light irradiation. The composite with 1% weight content of Bi 2 O 3 to g-C 3 N 4 exhibited the highest photocatalytic activity with an apparent rate constant of 0.063 min −1 , which was 3.0 and 3.7 times higher than that of pure Bi 2 O 3 and g-C 3 N 4 , respectively. The enhanced photocatalytic activity of the Bi 2 O 3 /g-C 3 N 4 composite was mainly attributed to the improved charge separation efficiency and stronger redox ability. This work gave a new insight in developing g-C 3 N 4 -based Z -scheme heterojunction photocatalysts with enhanced photocatalytic activity.