Ag/α-Fe2O3/g-C3N4 nanocomposites as Z-scheme heterojunction photocatalysts for degradation of RhB

In this study, Ag/α-Fe2O3/g-C3N4 composites with varying α-Fe2O3 and Ag contents were synthesized by loading α-Fe2O3 and Ag nanoparticles onto the g-C3N4 with a high specific surface area via acid annealing. These composites were then utilized for the photocatalytic degradation of RhB under the irradiation of visible light. For α-Fe2O3/g-C3N4 composites with 5 wt.% content of α-Fe2O3, the degradation efficiency reached a peak of 97.57% within 55 min, which was much higher than that of α-Fe2O3 and acid-annealed g-C3N4 with 45.92% and 83.61%, respectively. Furthermore, the photocatalytic degradation efficiency of Ag/α-Fe2O3/g-C3N4 composites reached its maximum of 99.61% with 1% content of Ag. It was demonstrated that the ternary Z-scheme heterojunction construction leaded to a significant enhancement of carrier separation and transfer effects, while the incorporation of Ag serves as electron reservoirs and photoinduced electrons capturers, thereby significantly enhancing the Fenton reaction and photocatalytic performance. This work is significant to drive the widespread application of g-C3N4 based heterojunctions in photocatalytic water purification.