Facile synthesis of tin oxide nanocrystals and their photocatalytic activity

Tin oxide nanocrystals with diameters smaller than 10 nm were synthesized using Na2SnO3 and CO2 as reactants and cetyltrimethylammonium bromide (CTAB) as stabilizer under mild conditions. As a mild acidic gas, CO2 is favorable for the accurate adjustment of pH value of Na2SnO3 solution. Stannate salt is stable, cheap and easy in operation. The effects of Na2SnO3 concentration, CTAB concentration, aging temperature, and aging time on the nanocrystals were studied. It was found that, with the increasing Na2SnO3 concentration, aging temperature and aging time, SnO2 nanocrystals size decreases. The formation of SnO2 nanocrystals can be interpreted by electrostatic-interaction mechanism. SnO2 nanocrystals show high photocatalytic activities in the degradation of Rhodamine B solution. The catalytic activity of small nanocrystals is higher than that of large ones.