Sulfur precursor and citric acid effect on SnS2 nanoparticles and their influence on the photodegradation activity of selected organic compounds

Semiconductor nanoparticle-mediated photocatalysis is an attractive option for water decontamination, being the semiconductors as SnS 2 with a bandgap in the visible region, the most promising materials. In the present work, we evaluated the influence of important parameters in the photocatalytic application of SnS 2 nanoparticles. Our results show that the presence of citric acid (used as a capping agent) restricts the formation of hexagonal nanoparticles. We also demonstrated that using thioacetamide as a sulfur source results in smaller nanoparticles than thiourea, 24.0 nm and 616 nm respectively. Moreover, small hexagonal nanoparticles play a key role in the photocatalytic activity of SnS 2 nanoparticles. Compared with TiO 2 performance, SnS 2 nanoparticles exhibited faster kinetics for methyl orange (MO) degradation, Kapp = 0.0102 min −1 , and 0.029 min −1 , respectively. We proved that SnS 2 is capable of breaking the azo bond of methyl orange by direct reduction. Furthermore, our analyses indicate that SnS 2 nanoparticles do not degrade atrazine and imazapic, but the photocatalytic route of metribuzin competed with photolysis, resulting in a particular transformation product that was not obtained with light irradiation only. We demonstrated that SnS 2 nanoparticles have high bond selectivity for azo breaking. Furthermore, they represent an advance for the development of designed materials (such as heterostructures), where the properties of SnS 2 can be tuned.