Construction of 2D/2D g-C3N4@Bim+1Fem-3Ti3O3m+3 (m=4, 5, 6) S-scheme heterojunctions for efficient photocatalytic tetracycline degradation

Aurivillius phases with narrow band gaps have attracted extensive interest in the field of photocatalysis, however, they exhibit poor activity due to the low utilization of photogenerated carriers. Herein, a series of S-scheme C3N4@Bim+1Fem-3Ti3O3m+3 (m = 4, 5, 6) heterojunctions with two-dimensional structures were synthesized by simple two-step method. Compared with single materials, the composites exhibit excellent photocatalytic tetracycline degradation under visible light, and 91.8% of tetracycline can be degraded accompanied with 81.2% of TOC removal within 120 min over C3N4@Bi5FeTi3O15. The enhanced photocatalytic performance is due to strong interface interaction, high conductivity, and efficient charge separation ability. The mechanism analysis indicates that the C3N4@Bi5FeTi3O15 heterojunction follows an S-scheme heterojunction mechanism with a strong interfacial internal electric field directed from C3N4 to Bi5FeTi3O15, thus, the photogenerated electrons in Bi5FeTi3O15 move toward C3N4, which retains high oxidation ability of -Bi5FeTi3O15 and high reduction ability of C3N4 to efficiently produce the reactive species, such as O-2(-)center dot and center dot OH.

Automated summary

A series of S-scheme C3N4@Bim+1Fem-3Ti3O3m+3 (m = 4, 5, 6) heterojunctions with two-dimensional structures were synthesized, which exhibited excellent photocatalytic tetracycline degradation under visible light. The enhanced performance was attributed to strong interface interaction, high conductivity, and efficient charge separation ability.