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 mu M 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.

Automated summary

The shape-dependent interaction of silver nanostructures (nanoparticles, nanowires, and nanocubes) with mercury (Hg2+) has previously been developed by our group. In this study, we investigated the effect of shape-dependent interaction between silver nanotriangles (AgNTs) and mercury using a simple colorimetric method based on the optical interaction between silver and mercury. The AgNTs were synthesized via a chemical reduction method and characterized using various analytical techniques. Upon interaction with mercury, a transformation from blue to purple color was observed due to the formation of Ag/Hg amalgam. This formation was confirmed by changes in the optical properties and morphology of the AgNTs. Furthermore, disposable paper strips were prepared by immobilizing the AgNTs on paper using a drop-casting method and evaluated for their ability to detect Hg2+. The AgNTs-based optical sensor exhibited high sensitivity and selectivity towards Hg2+ without the need for functionalization or additional molecules. The maximum detection limit of the sensor was calculated to be 0.8 μM. These results highlight the significant impact of nanostructure nature on the interaction between AgNTs and mercury, and suggest the potential of the proposed AgNTs-based visual and optical sensor for Hg2+ detection.