Self-Assembled NiWO4 Nanoparticles into Chain-like Aggregates on DNA Scaffold with Pronounced Catalytic and Supercapacitor Activities

We report a new route for the self-assembled NiWO4 nanoparticles (NPs) in chain-like aggregates on a DNA scaffold by the reaction of nickel(II) acetate with sodium tungstate under continuous stirring and heating at 60 degrees C within 90 min of reaction. The size of the individual NiWO4 particles was found to be similar to 20-30 nm and the diameter of the aggregates was in the similar to 220 +/- 30 nm range. The probable growth mechanisms of DNA-NiWO4 chain-like aggregates were elaborated. The potential of the NiWO4 chain-like aggregates was tested in catalytic reaction and in electrochemical supercapacitor studies. Catalysis study revealed that the NiWO4 aggregated structure acts as a suitable catalyst for the conversion of K-3[Fe(CN)(6)] to K-4[Fe(CN)(6)] in the presence of Na2S2O3 under UV-light illumination within a short time. Supercapacitor study signified that different morphologies of NiWO4 show different specific capacitance (C) values, and the highest C value of 173 F g(-1) at a scan rate of 5 mV s(-1) was observed while chain diameter was less. The supercapacitor study also revealed an excellent long cycle life along with 90% retention of C value even after 1000 consecutive times of cycling. The exploitation for the synthesis of mixed metal oxide on DNA scaffold might generate a new avenue for the successful formation of other oxides and can be useful for organic catalysis reactions and in future energy storage devices.