Reactive and photocatalytic degradation of various water contaminants by laser ablation-derived SnOxnanoparticles in liquid

Abstract

Reactive non-stoichiometric tin oxide (SnO_x) nanoparticles were facilely obtained by laser ablation of Sn in water using a fundamental nanosecond pulse laser. The size of the primary nanoparticles increased and the crystallinity spontaneously improved without heat treatment when the colloidal solutions were aged in the dark. Interestingly, such ageing-induced self-crystallization processes were considerably different from those in the colloidal solution illuminated by sunlight and/or ultraviolet light. Both the primary amorphous SnO_x nanoparticles and the aged nanocrystals were used for water purification; the contaminants studied included methyl orange, methylene blue, pentachlorophenol, and dichromate. All removal treatments produced good results, and had high degradation rates. Comparison with experimental investigations revealed that nanoparticles synthesized using conventional methods, such as sol–gel synthesis, showed poor performance or had no effect on the removal of water contaminants. In contrast, SnO_x nanoparticles derived by laser ablation in liquid possessed high surface reactivity, and the corresponding aged nanocrystals exhibited enhanced photocatalytic activity compared with commercial SnO₂ nanoparticles. These materials may be used in wastewater purification.