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[Display omitted] • SrSnO 3 /g-C 3 N 4 composite was directly prepared via a simple and rapid one-step thermal polymerization method. • The prepared material shows excellent activity under sunlight. • SrSnO 3 /g-C 3 N 4 has good catalytic activity under the synergistic effect of adsorption and dry photocatalysis. • The heterojunction showed reduced recombination rate compared to pure materials. The SrSnO 3 /g-C 3 N 4 , 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) SrSnO 3 :g-C 3 N 4 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. [ABSTRACT FROM AUTHOR]

The presence of organic pollutants in the environment, especially in water, is recognized as a continuing threat to environmental stability. Therefore, the development of new materials for the removal of organic pollutants in water are of fundamental importance. In this paper, a heterojunction SrSnO 3 /g-C 3 N 4 photocatalytic system was synthesized and its photocatalytical performance for Rhodamine-B (RhB) degradation has been tested. For this purpose, in situ luminescence measurements were carried out for the first time here, for monitoring the photodegradation process in real time under real reaction conditions performance. The degradation profiles of RhB using the SrSnO 3 /g-C 3 N 4 composite and pure g-C 3 N 4 showed that the degradation of the dye occurs through different mechanisms including four processes: N-de-ethylation, chromophore cleavage, opening-ring and mineralization. The results demonstrate that the SrSnO 3 /g-C 3 N 4 ratio 1:1 (SSO3) and 1:2 (SSO4) provide high photocatalytic activity under solar light. Best results were observed for composite SSO3, which displayed TOC removal of 97.3 ± 0.03 % after 4 h of solar exposure, while SSO4 and pure g-C 3 N 4 obtained a rate of 72.4 ± 0.03 % and 44.6 ± 0.04 %, respectively. Result of in situ experiments showed that composite SSO3 was 1.7 times more efficient in the RhB degradation than pure g-C 3 N 4. The toxicity of phototreated solution was evaluated by Fish Embryo Test (FET) showing the successful photodegradation of RhB to non-toxic species. [ABSTRACT FROM AUTHOR]

The SrSnO 3 was prepared in powders form by a conventional method of solid state reaction and submitted to thermal treatment under NH 3 in order to obtain the oxynitride and then promote photocatalytic activity at the visible region. Three different nitridation conditions were tested. The results showed that when the SrSnO 3 is subjected to nitridation at moderate conditions (600 °C and 650 °C) oxynitide is formed preserving the perovskite structure. On the other hand, when the nitridation occurs at more severe conditions (750 °C), it is possible to observe the decomposition of the structure instead of the incorporation of N. Samples in which oxynitride is formed, SrSnO 3 :N, showed high potential photocatalysis under visible light, showing to be about 4 times more active than SrSnO 3 or TiO 2 at the same conditions. [ABSTRACT FROM AUTHOR]

Abstract: Semiconductor materials have received substantial attention as photocatalysts for controlling water pollution. Among these materials, perovskite-structured SrSnO3 is a promising candidate for this application, whereas BaSnO3 exhibits very low activity. In the present work, Sr1−x Ba x SnO3 (x = 0, 0.25, 0.50, 0.75 and 1) was synthesized by solid-state reaction and was applied in the photocatalytic discoloration of the organic dye Remazol Golden Yellow. The perovskite structure was obtained for all compositions of the solid solutions with both Sr2+ and Ba2+ present in the lattice. A remarkable change in the short-range symmetry was observed as the amount of Ba2+ increased, and this change led to a decrease in the band gap of the material. Although the BaSnO3 was not active toward water photolysis, the discoloration induced by this perovskite was twice that induced by SrSnO3. The two materials appear to feature different mechanisms of photodegradation: the direct mechanism prevails in the case of BaSnO3, whereas the indirect mechanism appears to play a key role in the case of SrSnO3. [Copyright &y& Elsevier]