Ruthenium Nanoparticles Mediated Electrocatalytic Reduction of UO22+ Ions for Its Rapid and Sensitive Detection in Natural Waters.

Reduction of UO22+ ions to U4+ ions is difficult due to involvement of two axially bonded oxygen atoms, and often requires a catalyst to lower the activation barrier. The noble metal nanoparticles (NPs) exhibit high electrocatalytic activity, and could be employed for the sensitive and rapid quantifications of U022+ ions in the aqueous matrix. Therefore, the Pd, Ru, and Rh NPs decorated glassy carbon electrode were examined for their efficacy toward electrocatalytic reduction of UO22+ ions and observed that Ru NPs mediate efficiently the electro-reduction of UO22+ ions. The mechanism of the electroreduction of UO22+ by the RuNPs/GC was studied using density functional theory calculations which pointed different approach of 5f metal ions electroreduction unlike 4p metal ions such as As(III). RuNP decorated on the glassy carbon would be hydrated, which in turn assist to adsorb the uranyl sulfates through hydrogen bonding thus facilitated electro-reduction. Differential pulse voltammetric (DPV) technique, was used for rapid and sensitive quantification of UO22+ ions. The RuNPs/GC based DPV technique could be used to determine the concentration of uranyl in a few minutes with a detection limit of 1.95 ppb. The RuNPs/GC based DPV was evaluated for its analytical performance using seawater as well lake water and groundwater spiked with known amounts of UO22+.