Nanocomposites of SnO2 and g-C3N4: Preparation, characterization and photocatalysis under visible LED irradiation

Abstract

Tin dioxide nanoparticles were prepared in the presence of graphitized carbon nitride (g-C3N4) forming nano composites with different contents of SnO2 up to 40 %. G-C3N4 was synthetized by heating of melamine at 550 degrees C in the open air and Sn2+ ions were precipitated by sodium hydroxide in g-C3N4 aqueous dispersions. Resulting mixtures were dried by freezing at -20 degrees C and calcined at 450 degrees C to obtain SnO2/g-C3N4 nanocomposites.

The nanocomposites were characterized by common characterization methods in solid state and in their aqueous dispersions using dynamic light scattering (DLS) analysis and photocatalysis. SnO2 nanoparticles in the nanocomposites were found to have an average size of 4 nm, however, those precipitated without g-C3N4 had an average size of 14 nm. Separation of photoinduced electron and holes via heterojunction between SnO2 and gC(3)N(4) was demonstrated by photocatalytic decomposition of Rhodamine B (RhB) under LED visible irradiation (416 nm) and photocurrent measurements. The most photocatalytically active nanocomposite contained 10 % of SnO2. Graphitized carbon nitride was assumed to serve as a template structure for the preparation of SnO2 nanoparticles with a narrow size distribution without using any stabilizing additives.