Shape dependent interaction of silver nanostructures with mercury for its sensing applications

Development of shape dependent interaction of silver nanostructures (Nanoparticles, Nanowires, and Nanocubes) with mercury (Hg2+) for its sensing applications has been accounted earlier by our group. For the continuation of our work, we have studied the effect on shape dependent interaction of silver nanotriangles (AgNTs) with mercury by simple colorimetric method through the optical interaction between silver and mercury. Here, AgNTs were fabricated by chemical reduction method and characterized by various analytical techniques. On interaction of AgNTs with mercury, it shows a significant transform from blue to purple owed to the development of Ag/Hg amalgam. Also, the formation of amalgam was confirmed by the change in the optical property of AgNTs. HR-TEM results reveal that the morphology of AgNTs has been changed from nanotriangle to nanoparticles on interaction with mercury. Moreover, disposable paper strips were prepared by immobilizing the AgNTs on top of the paper slip by drop casting method and evaluated for determination of Hg2+. It shows analogous characteristics with reverence to sensitivity and selectivity under optimized conditions. The maximum detection of AgNTs based optical sensor was calculated and accounting to be 0.8 µM towards Hg2+. Results clearly show that changing the nature of the nanostructures might have an excellent effect on interaction between AgNTs with mercury. Hence, proposed AgNTs based visual and optical sensor is highly selective and sensitive towards Hg2+ without any functionalization or addition of molecules.