Thiophene insertion and lanthanum molybdate modification of g-C3N4 for enhanced visible-light-driven photoactivity in tetracycline degradation

This work was designed to enhance the photocatalytic activity of g-C3N4 nanosheets via the insertion of thiophene group and modification of La-2(MoO4)(3) nanoparticles with a size of 200-600 nm. The insertion of thiophene ring into the g-C3N4 matrix introduced an additional absorption at about 500 nm, which greatly extends the optical property of g-C3N4. Additionally, the thiophene group can also increase the separation of photo generated electron-hole pairs via promoting electron delocalization. La-2(MoO4)(3) was closely loaded on the surface of thiophene inserted g-C3N4 (TPCN), which is conducive to the migration of electrons between them. Because of the lower conduction band (CB) of La-2(MoO4)(3) than TPCN, the photoexcited electrons in TPCN can migrate to the La-2(MoO4)(3) CB to further suppress the recombination of electron-hole pairs, which finally results in the enhanced photoactivity under visible light. The optimal La-2(MoO4)(3)/TPCN composite presents a tetracycline (TC) degradation rate of 0.048 min 1, which is 3.4 and 1.8 times higher than that of g-C3N4 and TPCN, respectively. The cycling tests further demonstrated that the La-2(MoO4)(3)/TPCN hybrid has good stability in photocatalytic degradation of TC. This result once again emphasizes the benefits of promoting the photoactivity of g-C3N4 through the combined action of doping and surface modification.

Automated summary

This work aims to enhance the photocatalytic activity of g-C3N4 nanosheets through the insertion of a thiophene group and modification of La-2(MoO4)(3) nanoparticles. The insertion of the thiophene ring extends the optical property of g-C3N4 and promotes electron delocalization. La-2(MoO4)(3) loaded on the surface of thiophene-inserted g-C3N4 facilitates electron migration and suppresses the recombination of electron-hole pairs, resulting in enhanced photoactivity. The La-2(MoO4)(3)/TPCN composite exhibits a significantly higher degradation rate than g-C3N4 and TPCN, and shows good stability in photocatalytic degradation.