Bismuth Molybdate/Graphene Nanocomposite for Electrochemical Detection of Mercury

We developed a flexible electrode based on a bismuth molybdate/graphene (BiM/GR) nanocomposite for electrochemical detection of mercury (Hg2+). The formation of the BiM/GR nanocomposite was systematically examined with suitable characterization studies. The BiM/GR-modified electrodes exhibit a high electrocatalytic performance toward Hg2+ detection comparable to other electrodes. The excellent electrocatalytic activity of the BiM/GR nanocomposite can be attributed to its good conductivity, synergistic effect, and abundant active site. Notably, the BiM/GR sensor showed good electrochemical sensing performance for Hg2+ in the wide detection range from 0.02 to 149 μM with a good sensitivity of 9.5 μA μM–1 cm2 and an ultralow detection limit of 5.0 nM, which is well below the threshold value set by the World Health Organization (30 nM) and the United States Environmental Protection Agency. More importantly, the BiM/GR nanocomposite-modified electrode was used successfully to detect Hg2+ in river water, corn, and fish samples with satisfactory recovery values.