Facet exposure engineered S-scheme g-C3N5/BiVO4 heterojunction for enhanced photocatalytic degradation of ceftriaxone sodium

g-C 3 N 5 /BiVO 4 - x heterojunctions with tunable BiVO 4 facet ratios were fabricated. • g-C 3 N 5 /BiVO 4 -F shows best activity via suitable (121)/(040) and (040)/(011) ratios. • H 2 O 2 addition boosts photocatalytic degradation efficiency of ceftriaxone sodium. • In-situ XPS confirms the S-scheme charge transfer in g-C 3 N 5 /BiVO 4 -F heterojunction. S-scheme heterojunctions have garnered significant attention in the photocatalytic degradation of antibiotics due to the efficient charge separation and strong redox capability preservation. However, photocatalytic activity is highly dependent on the exposed crystal facet ratios of the catalyst. A series of g-C 3 N 5 /BiVO 4 (N-CN/BiVO 4 -x) S-scheme heterojunctions were fabricated by tuning the morphology of BiVO 4 into peanut-like (BiVO 4 -P), flake-like (BiVO 4 -F), and decahedral structures (BiVO 4 -B), thereby controlling the ratios of exposed crystal facets. Degradation performance tests revealed the optimal performance of N-CN/BiVO 4 -F. This heterojunction achieved a degradation rate of 71.1% for ceftriaxone sodium (CS). With the introduction of H 2 O 2 , the degradation rate further increased to 85.1%. The results confirmed that the superior performance of N-CN/BiVO 4 -F is closely related to the specific exposure ratios of its (121)/(040) and (040)/(011) crystal facets. Furthermore, in-situ XPS confirmed that the charge transfer follows S-scheme charge transfer mechanism. Photoelectrochemical measurements and radical trapping experiments revealed a possible CS degradation mechanism. This work elucidates how the exposed facets of BiVO 4 regulate the photocatalytic performance of S-scheme heterojunctions. The findings provide a theoretical and practical basis for designing efficient photocatalysis systems. Download: Download high-res image (92KB) Download: Download full-size image