Indium selenide/silver phosphate hollow microsphere S-scheme heterojunctions for photocatalytic hydrogen production with simultaneous degradation of tetracycline

Designing heterojunction photocatalysts with strong interfacial interactions is an effective way to reduce the recombination of photogenerated charge carriers. Here, silver phosphate (Ag3PO4) nanoparticles are coupled with hollow flower-like indium selenide (In2Se3) microspheres by a facile Ostwald ripening and in-situ growth method, resulting in the construction of In2Se3/Ag3PO4 hollow microsphere step-scheme (S-scheme) heterojunction with a large contact interface. The flower-like In2Se3 with hollow and porous structure provides a large specific surface area and numerous active sites for photocatalytic reactions to take place. The photocatalytic activity was tested by measuring the hydrogen evolution from antibiotic wastewater, and the H2 evolution rate of In2Se3/Ag3PO4 reached 4206.4 µmol g-1h−1 under visible light, which is approximately 2.8 times greater than that of In2Se3. In addition, the amount of tetracycline (TC) degradation when it was used as a sacrificial agent is about 54.4% after 1 h. On the one hand, Se-P chemical bonds act as electron transfer channels in the S-scheme heterojunctions, which can facilitate the migration and separation of photogenerated charge carriers. On the other hand, the S-scheme heterojunctions can retain the useful holes and electrons with higher redox capacities, which is very favorable for the generation of more •OH radicals and the photocatalytic activity is greatly enhanced. This work provides an alternative design approach for photocatalysts toward hydrogen evolution in antibiotic wastewater.