Fabrication of a dual S-scheme S-doped g-C3N4/In2S3/TiO2 muti-heterojunction photocatalyst for significantly enhanced photocatalytic degradation performance toward organic pollutants

This work constructs a dual S-scheme S-C3N4/In2S3/TiO2 multi-heterojunction via ball-milling. The S-C3N4/In2S3/TiO2 showing significantly enhanced photocatalytic degradation activity for rhodamine B and tetracycline. The photocatalytic performance under different pH and anion environments demonstrate that an acidic environment favors the effective removal of tetracycline by S-C3N4/In2S3/TiO2, while HCO3- and CO32- exert obvious inhibitory effects on the photocatalytic process. In-depth mechanistic investigations indicates that the S-C3N4/In2S3/TiO2 multi-heterojunction system follows a dual S-scheme photogenerated charge transfer pathway. This enables efficient separation and migration of photogenerated carriers, generating abundant reactive oxygen species to participate in the photocatalytic process, thereby effectively improving the photocatalytic performance.