Selective detection of Cd (II) and Cr (VI) ions using rGO functionalized metal doped SnO2 nanocomposites

Abstract

This research gives a valuable insight for understanding the effect of doping on morphology and rGO functionalization on electrochemical sensing. Firstly, hydrothermal method was used to synthesize pure SnO2, cobalt (Co) doped and iron (Fe) doped SnO2 nanocomposites. Doping of Co/Fe into SnO2, gradually attract spherical nanoparticles together to form a three-dimension cube-like structure. Considering the potential of these morphological changes, their heavy metal ions (HMIs) sensing properties have been further investigated. The results revealed that the type of dopants (Co/Fe) and their morphologies have a significant impact on the HMIs sensing performance. 1 wt% doping of Co and Fe into SnO2 shows highest selectivity (∼2.3 – 8.4 (Co doping); ∼2–13 (Fe doping)) and sensitivity (∼1.4 µA/ppb (Co doping); ∼2.6 µA/ppb (Fe doping)) toward cadmium (Cd (II)) and chromium (Cr (VI)) ions respectively as compared to other HMIs. Furthermore, reduced graphene oxide (rGO) functionalized Co doped and Fe doped SnO2 nanocomposites were synthesized using ultrasonication method. The rGO functionalized metal doped nanocomposites improve HMIs sensing performance than pure and metal doped SnO2 nanocomposites. According to electrochemical studies, the synthesis of nanocomposites with strong electrocatalytic activity and enhanced active surface area is primarily responsible for improved sensor response.