SrSnO3/g-C3N4 dry phase sunlight photocatalysis

Abstract The SrSnO3/g-C3N4, a multifunctional composite, was synthesized by a facile solid-state in-situ synthesis strategy and applied to visible light-mediated photocatalysis in both, wet and dry phase. In the dry phase, unconventionally, the heterojunction adsorbs the test molecule Methylene Blue (MB) and photocatalytic reaction takes place in a solid phase through direct exposure of a small volume of material to sunlight. Best results were achieved using 1:1 (w/w) SrSnO3:g-C3N4 heterostructure, probably due to the lowest recombination rate associated to a high rate of reactive oxygen species (ROS) formation. Under the best conditions, 100 % of MB adsorption followed by 89 ± 1 % of organic matter removal was achieved after 240 min of sunlight exposure. Use of a dry phase presented the advantage of a need for less material. In the conventional wet phase route, 97 ± 1 % of organic matter removal was achieved under similar conditions. After exposure to sunlight, degradation by-products (wet phase) and powder (dry phase) no longer showed phytotoxicity to lettuce seeds (Lactuca Sativa). This study presents a strategy for visible light photocatalysis not mediated by a hydroxyl mechanism.